Tire testing. Recommendations.
Wheels, rim shapes, spacers, nitrogen, wet roads, tire
markings, hydroplaning, etc.
© Copyright, 2014, R. Fleischer
article #54, section 5
It is difficult to maintain a list of recommended tires due to changes in what is available; and, what I have ridden & tested. Up until a few years ago, I was putting on rather high mileages every year; and, testing riding many Airheads besides my own; PLUS, my tire testing was vigorous ...& rather formal. As I approach 80, I am putting on far fewer miles these days, &
have been reducing the vigorousness of testing. I have, effective September 1, 2016, for two-wheelers, limited: (1) on-purpose corner sliding; (2) full-on panic-stopping on both dry & wet roads. This does not mean that such testing has stopped completely; and, some of my testing is still rather more vigorous than most riders will do.
In the past I had not often included other's remarks about tires that I had not personally ridden & tested. I now have three people, whose serious tire testing mirrors mine close enough. I have begun to include their input. I list some discontinued tires on purpose, for reference & comparison; ALSO, Some old style tires are now being re-made, often with updated rubber and possibly construction.
MORE information is located in:
http://bmwmotorcycletech.info/wheels.htm Detailed information on wheels, and see next line too....
http://bmwmotorcycletech.info/section6.htm Gets heavily into tube & tubeless, on various rims.
Some words of caution, & STRAIGHT TALK:
Some tire testing is easy & this is the type MOST TYPICALLY reported or commented-on (Lists, Forums, ETC). Mostly JUST OPINION, with LITTLE REAL FACTS. Sometimes it is not even real opinion, but someone wanting to say something to feel part of the group.
Better type of commentary comes from those who generally do the following things:
You keep your tires inflated properly. You ride like you usually do, mostly on paved roads with mixed speeds, and are willing to state accurately the types of speeds you use because speed affect tire wears to quite some extent. You do mixed type of curves, mixed type of road roughness, mixed loading. If you ride two-up a lot, you note that in your records. If your loading is high, you note that. You write down the odometer reading when you put the tires on & when you take them off for replacement. Perhaps you always replace tires when the center of the tread is 1/16" deep. If not, you make note. You write the mileage down, subtract, & now you have YOUR typical mileage for YOUR usage on THAT tire, at YOUR weights/loading, speeds, & tire pressures. Perhaps you do testing at various tire pressures before beginning the ride. Maybe you write down how easy, or how difficult it was to mount the tire. This can all be useful information. But, in your 'opinions', do you specify EXACTLY all the facts about riding style, pressures, loads, types of roads ... & many other things? If you say you are aggressive, JUST WHAT DOES THAT REALLY MEAN? Would you be able to write a report, that not only gives real testing facts, but recommendations made from honest comparisons against many other brands & models, ETC.?
Typical comments on various forums when discussing motorcycle tires is about "how well the tire sticks to the road"; & how many miles before it wore out. In a rather large percentage of instances, no 'standards', only minimal information opinions, are seen in discussions. The bald truth (BAD pun!) is that modern tires are vastly better than the tires were when your Airhead was manufactured (particularly before the nineties, and in some instances quite recently), & unless you have REAL racetrack experience, you are UNLIKELY to be capable of putting the tire to real testing, let alone out-riding the tire. Have you REALLY tested/ridden to see if/when/how/conditions that the front wheel looses traction? When does it lose the 'sticks to the road' performance you posted about....? What about your bike's suspension ...it has a HUGE amount to do with how the front tire 'sticks' to the road, particularly if the road is not dead-perfectly flat 100%. I'm not overly nice, am I?
Your Airhead is of limited power, limited braking, & may have suspension aging or improper setup problems ...all of which affect tire life (AND handling!). Even when a number of modifications are made, these are still NOT 170 mph crotch rockets.
Serious accidents can occur with something as simple as a tight turn, especially at speed, especially with a rear tire tread that has been worn more than somewhat (the center of the tire tread flattened), when it originally was rounded to some degree. Do you KNOW about flat-worn rear tire stability problems? If you had a motorcycle that went into high speed wobbles or oscillations, would you blame the bike, the rear tire, maintenance of some 'guessing' sort, or, just what would you say, publicly? Is the 'report' USEFUL? ACCURATE?
IF you tried to duplicate my style of testing (particularly when I was younger) & the testing or at least educated experience from those who ACTUALLY put their tires 'to the test', perhaps on racetracks, or in serious dirt conditions ...you could be asking for serious trouble. You probably know this, yet probably don't want to admit it.
ASK YOURSELF: Are you REALLY competent at riding to the tire slipping point, over and over again, on purpose? What about crossing up the steering during sliding? Does that idea of crossing-up the steering freak-you out? On wet roads? What about when your beautifully executed carving turn encounters lots of bumps? Sudden off-banked tight turns? Washboards? Can you truly (be honest!) feel the difference a FEW pounds of pressure makes? Have racetrack & soft dirt/gravel & wet roads experience? Are you truly smooth with the controls (including transmission, brakes, clutch & throttle)? Are you smooth with transitions from any surface or turn direction, etc.? Tires DO vary considerably, in how they handle, how they wear, & under what types of conditions (including road surfaces, straights, turns, off-banks, braking in dry good friction areas versus wet roads ....what about deeper water on those roads? What characteristics of a tire do you REALLY need? Be honest with yourself! Even in an 'emergency maneuver', ask yourself, just how much you will really push your tires. Do you know that super-performance tires may well NOT be the type YOU should use? Do you know why this is so?
PROBABLY quite a few tires will work well for most any type of riding you do. BUT, you MAY be the type of rider that really IS aggressive, or has special needs. Perhaps you really do ride off-road, into seriously soft stuff, mud, single track trails, real Adventure Riding ...are you going to ride on pavement to get there? Maybe you really ARE an aggressive road rider, maybe you get off-road now and then, maybe only into mild dirt and abrasive gravel? Perhaps you, like most motorcyclists, love carving turns at speed on paved roads. Are those turns nice sweepers, or tight twisties on, perhaps, narrow roads? What about the FEEL of your tires in tight twisties, especially when very quickly changing directions? Perhaps you REALLY use the front brake truly hard. Do you brake in turns? Are you carving the same turns quite precisely, turn after turn? Perhaps you ARE a real all-weather rider; maybe you use your motorcycle as your primary transportation, year-round. Riders have different real needs for their tires.
I try to cover most all uses & rider types for specific tires. Since there is so much interest in tires, I offer a fair amount of information in this article. I will try to separate anecdotes from facts. I try to separate those whose input comes from racing experience, from those with road experience. I try to do THAT in several ways. Keep in mind that when a very experienced track racer rides a bike on the streets & highways, their expressed viewpoints about their tires tends, rather strongly, to be a comparison between how a RACE BIKE handled on a RACETRACK with REAL racing tires ...compared to what the street bike (which may even be a high performance type) feels like on street-riding tires. This may NOT BE OF REAL VALUE TO YOU, the average, even somewhat aggressive street rider. In MY experience, SOME real racers are milder in street riding than you may think ...but, they ALSO may be VERY aggressive AT TIMES in such as tight twisties. Thus, their remarks about tire feel & mileage may be very different from your input, even if you say, & possibly ARE, aggressive in your riding.
Do YOU square off your rear tire in your riding? ...do you wear the sides of the tread very noticeably? How do reports from these various types of riders vary? Why? Will YOU ever ride in the twisties to even close to the extent & aggressiveness of someone with a LOT of track experience, particularly on track type racing tires? If YOUR proposed tires are a type that such expert and aggressive riders like, will YOU like them?
Did you KNOW that quite high performance tires can be dangerous to non, or moderate riders? There ARE reasons to NOT get the "best" tire, whatever that word will mean.
Be VERY cautious about whose words you listen to (and try to emulate). ULTIMATE road performance to modern performance standards MAY WELL not be what YOU are going to be REALLY interested in ...and those tires may not give you mileage and value ...and might feel twitchy, etc. You may be disappointed in the tires (or, worse, you describe them as wonderful, when you do not really believe that ...worse yet, if you can't really feel differences and so describe them as wonderful).
Riders want, more than they need, more information on tire brands, models, & characteristics; & for conditions they may never encounter. This is very much like doing discussions over a few beers or around the campfire, or 'garage racing'. In MANY instances, stated viewpoints on their own tires are NOT substantiated by real testing. I hope to provide REAL information in this article. Tire threads can be like oil threads on internet lists!
I RECOMMEND YOU DO NOT TRY TO DUPLICATE MY TESTING METHODS UNLESS YOU ARE COMPETENT TO DO SO, & ARE WILLING TO TAKE ON THE RISKS OF DOING SO. I AM NOT RESPONSIBLE FOR YOUR INCIDENTS & ACCIDENTS!
For NEW tires, my habit is to run the tires in reasonably for 50 to 100 miles, slowly increasing aggressiveness over those miles. I make notes, play with tire air pressures (I take along a small electric compressor & I use a very accurate Bourdon type gauge) ...& when I find hot/warm pressures that work well, I recheck with the tires cool, so I know what the normal tire pressure should be (tire pressures for normal use are initially checked with the tires cool, that is, not ridden yet).
Testing informs, for any one particular bike, how a tire can be expected to work ...this testing should include panic situations & pushing things aggressively in various types of turns. I like to do sharp corrections in mid-turn for additional information. Properly done, testing allows comparison between various tire makes & models; & THIS IS MY PRIME GOAL.
I have certain testing areas very close to my home in California that I have consistently utilized since 1973, depending on time of year and conditions. One area has THREE moderately steep & twisty mountain passes. They have a mix of asphalt & cement surfaces & a mixture of tar snake repairs (excellent for testing suspension stiction). One stretch of road is often irregularly flooded in the Springtime with water for distances of 1/4th to 1/2 mile (I use it for curves & braking tests). This area has both rough, broken and smooth pavement. One area that seems to always be dry has rather rough & uneven pavement. That area also has off-camber curves! Off-camber curves are very interesting when testing tires that are fairly well-worn, and ""NOT fun"" with flat-worn rear tires.
If you visit my area, you're invited to ask me, directly, about various roads ...we might even go riding.
The rest of the details, before I get into the brands and testing results (followed by Everything Else):
1. Some types of tires do/did not work well on early Airhead motorcycles. TIRES BACK THEN REQUIRED LOWER TIRE PRESSURES; CONSTRUCTION OF THE TIRES WAS QUITE DIFFERENT THAN TODAY'S TIRES. Today's tires, with very few exceptions, use higher pressures, in some instances up to 10psi more. Failure to increase to proper pressure will give poor handling, particularly during transition from straight ahead to a turn. You can NOT depend on the tire maker to tell you the proper pressure for BMW Airheads ...they may want to limit any possible liability, so they simply quote what BMW said in original OLD sale literature.
We now have special radial tires for 'classic' motorcycles like our Airheads & the Classic K bikes. Most do VERY well. I think most of you will actually like these new radial tires ...even mild riders. Many of the newer non-radials are also excellent. BE SURE you use appropriate pressures in all tires.
LOWER profile tires (modest, such as 80 section) may not work well (exceptions depending on the tire, and if a Monoshock or Paralever, or a Classic K bike), & many simply will not properly fit old Airheads, they will rub something, including the swing arm. Generally a "90" profile works best on old Airheads. Unless I specifically make note in this article, assume that I used the stock tire sizes, or close metric 'equivalent'. I tried, when I could, to test inch sizes (when available, many tires are not available in inch sizes). Example: 4.00 x 18 rear original. Test in 4.00, 110, and 120. Another example: 3.25 x 19 front original, test in 3.25, 3.50, 90/90, 100/90. Similarly for the 18" front tires. In order to do some types of testing I had to be putting on huge mileages every year ...and I did ...I have my 600,000 BMW badge and credentials.
2. Frames & suspensions were designed by BMW for a specific feel & handling that BMW desired. Many seem to have no idea that frame design & construction, suspensions, & MANY other things, ALL, together, affect how a motorcycle feels, & one word is often used, without specifics: HANDLING. In common use are such terms as FEEL, TURN-IN, FALL-IN, TWITCHINESS, QUICKER-Handling, ....& other words, that you might think mean something very specific.
3. BMW used to issue bulletins with names/models/sizes of tires that BMW HAD TESTED & APPROVED; but that has not been done for Airheads since they were in production (with some very few exceptions).
4. Here is a link to a rather nerdy article. The article has extensive vector & other diagrams, & some conclusions about contact forces that may well astonish you. When you read it, keep in mind what REALLY happens when you are cornering. THINK about the effects of you changing a tire size....from, an example here, a 90/90 to a 100/90. What REALLY happens when you go to a larger size tires (larger width). You may be very interested.
One of the problems with trying various classic/heritage (or similar) tires is that MOST riders no longer have the exact same type of original shock absorbers & springs; or, those are not in good condition; or, other parts of the motorcycle have aged; or, they have made other changes. Just changing the type or style of handlebars WILL AFFECT the bike feel. If your bike is in reasonably decent condition & reasonably close to original specifications, you might really want to try a set of the old tires (which might well have some changes in them, so you might NEVER REALLY get the exact original feel as when the bike was brand-new). It REALLY IS worth trying these tires if you want to experience something close to original feel. If you don't like the tires, sell them to someone else.
6. I have personally ridden on quite a few modern tires, besides the really old type tires. MOST modern road type tires offer rather good road handling, quite decent predictability of handling in various situations, indication to the rider of what the tires are doing AND GOING TO DO; as well as comfort, load carrying, traction in cold/wet/dry & not unreasonable differences in handling between moderately wet & dry. A few don't let you know about handling limits ...until, suddenly, you are very aggressive.
One thing usually discussed, MILEAGE (tire wear), SHOULD NOT be "the" most important characteristic for most riders, although for some folks, who put on large yearly mileage, that can be of more importance ...so I DO get into recommended tires for mileage. MANY of today's tires, including re-incarnations of old styles, will have better mileage than long ago, even though these modern tires are not being sold as 'high mileage'. That is due to the use of different proportions of carbon black and silica's, and the widening use of different tire compounds in the center versus the sides.
7. There is a considerable difference in how tires FEEL to the rider & also differences, large ones, by various models of BMW Airhead motorcycles. Trail & suspension & wheel width differences are only a quite modest portion of the reasons. MOST ALL modern tires are capable of out-handling the bike & MOST RIDERS. They stick to the road rather well, even at big lean angles under fairly severe conditions at speed. That's the truth. BUT, there is another truth: the FEEL can make the rider THINK the bike is handling wonderfully; OR...poorly. When reading tire comments/reviews, FEEL is NOT well differentiated.
MANY modern tires have profiles, type of rubber, type of design, type of tread, ETC., that give a "quicker handling" feeling. Many modern tires FEEL to the rider, particularly when starting out on a new set of tires they have not ridden on before ...that they are considerably OVER-inflated, & might be called SKITTERY. 'Quicker Handling' is often the term used by those riders. Many riders are timid, particularly on wet roads ...but, the tires may feel ...or be described ...as quick, or twitchy, or skittery, etc. ...on dry roads too, even after thousands of miles on the same tires. Another truth is that riders transitioning to a modern tire that REQUIRES increased inflation pressure, might be using OUTDATED tire pressure information. This results in a very poor handling tire, typically a mushy-ness, tire-rolling sideways on the rim, type of feeling. MANY will equate THAT feeling with being skittery ....which is not really true. Still, the effect is BAD HANDLING.
Wet roads (and maybe even hard packed dirt and thin gravel) tend to create a considerable apprehension for many riders. Many riders did not experience wet roads much when learning to ride & are slightly to moderately freaked-out by the idea of riding in rainy conditions. In MY experience as a guide/teacher, these types of riders may also especially freak-out on gravel or dirt roads ...even at just the thought of being on gravel roads. I KNOW riders who are NOT going to attend a function, such as a TechDay, etc., if the driveway is gravel or steep. This is not an article about how to ride bikes, I am just telling the truth about various riders. If a rider is ACTUALLY timid (hard to find out!), how much weight will you give to this rider's opinions about tires? MAYBE YOU SHOULD pay attention ...you might be similar!! The truth is that most motorcyclists are NOT after anything hardly approaching racing experience. Many do NOT want to ride aggressively, most do want to be brisk at times. MANY are OLDER (especially BMW riders) & don't like 'taking chances' (which words have variable meanings to riders). Many riders are simply out for a "Gentleman's ride on Sundays"; or a mild to modest ride to a TechDay or camp-out. It is true, also, that many, if not most, like some occasional aggressive fun in twisties and sweepers. THAT, usually, is NOT at ALL the same as turn after turn, ETC., on a racetrack, on a race-prepared bike, with racing tires. It is also not usually the same as the aggressive rider who, turn after turn, pushes his bike hard into corners, and likes nothing more than a long series of VERY connected corners.
I NEED TO consider all riders in testing/talking about tires. That means I NEED TO consider all or you when reporting on tires. I try to analyze tire performance for ALL USERS. The exception is real RACING, where skills are likely quite high, aggressiveness is a given, special tires are in use, as are special techniques ...such as pre-warming the tires in the pits, wearing sidewalls rapidly, speeds are high ...& quite a few other things. I have not, but very seldom, reported on racing tires, and usually not in THIS article.
8. Mileage one gets from tires depends on speed, loading, tire pressure, road condition, temperature (including road surface temperature), style, etc. Be very cautious about who you listen-to. You may want to ask very detailed questions!
9. MUCH of what I hear and read about tires seems to be based on nothing but thin air, or ...the owner has purchased them & WISHES they tested as he says they do. The rider may also have NO IDEA of what he is talking about. I realize this is cynical, but it is the truth. I am WELL-AWARE that few do REAL tire testing, ...but many have UNsubstantiated "OPINIONS". In some instances, maybe a lot of instances, I wish I could share some teaching and riding.
A few more words about remarks made by others regarding their tire likes & dislikes:
a. FEW street riders ever come close to the potential of their tires, & fewer ever do strictly controlled testing.
b. Some ...well, actually MANY, reports on tires are wishful thinking.
c. Those whose background includes a lot of actual paved racetrack time have a strong tendency to report semi-race-performance as a comparison-evaluation on tires. This is not what my testing is about, for YOU. I am not going to compare a race-bike, with race tires, ridden hard, with hard riding on the street ...not even compare light racing. My testing is for real-world riders for commuting & touring use, who may or may not, sometimes, or even often, be brisk and aggressive. Be very cautious about who you listen to about tire performance, because riding briskly on public roads, is NOT the same as being on a racetrack trying to win a race (or, even just having a good time, & not going for a win), where tires are well heated-up, stick & handle very differently in almost every respect, including braking, transition between modes, flickability, etc. DO NOT let race-performance dictate YOUR tire purchases! ASK the reviewer, so-called-expert, etc., about his/her SPECIFIC testing details & COMPARISON METHODS.
10. I have tested tires on both asphalt roads (especially with various types of tar repair stripes, and washboard roads both of which also tests suspension stiction); concrete paved roads as well as gravel/hard-pack; and, occasionally rather soft stuff (yes, on road tires). I did REAL ACTUAL CONTROLLED TESTING. I have racing experience both on/off road, on 2-wheelers & sidecar rigs (sport cars too). I have available close-by my home some very specific roads that I have CONSISTENTLY used since 1973 for testing. These offer a wide variety of surfaces & conditions. I tested in below freezing temperatures, as well as warm Summers. I made a point of trying to ride when it rains, because it does not rain very much here. I even tested on somewhat icy and snowy roads. When I first moved here I had a R75/5 for good weather/roads ...but I also had a "light weight" (for back then!) dirt bike, shod with knobbies, that I rode in the snow. It was great fun but physically a lot of exertion ...but I was vastly younger then. I no longer do that in the snow (although I still do ride my sidecar rig in the snow ...lots of fun!).
11. Up until maybe 8 or 10 years ago, some tire sizes were getting hard to find in proper INCH sizes. While a number of the old sizes, such as 3.25-19, are available from several manufacturer's, some were not very commonly available. An particular example is the 3.25-18 used on the R45 and R65. HINT: Try:
http://www.durotire.com/ ....and click on CLASSIC (or similar word). BUT, do, FIRST, check into the Heritage line of tires from Metzeler, & the Continental classic tires, ....and the Bridgestone Accolade.
Many riders no longer use the classic inch sizes. NOW-A-Days, MANY inch-size tires are available again in various brands/models. MANY are using metric-sizes. But, many are now trying the newer inch-sized tires too. Several manufacturers now have tires specifically made & advertised for "Classic Bikes". These tires are really worthwhile looking into. This advice INcludes the new radial tires designed for our classic bikes. BTW...the old advice about not mixing up radials and bias ply tires on the same vehicle are, in MY OPINION, an old-wives tale, and do not much apply to MOST motorcyclists. You are on your own here though.
All these things, including suspension changes, pressure changes, etc., lead to a QUITE DIFFERENT ride from original stock configuration. Most riders just want a good ride with good handling & good tire longevity & don't really care about the 'classic' feel & handling. MANY have a lot of experience on other brands & models of bikes, & may want their Airhead to FEEL & HANDLE similarly, or 'just better', whatever THAT means to them. LOTS OF VARIABLES. It is DIFFICULT TO TEST TIRES WITH SO MANY IDEAS, SO
MANY TYPES OF RIDERS, SO MANY TYPES & STYLES OF TIRES. Think seriously about yourself, your abilities, your actual riding, TRY to KNOW what you like & want, & if you don't know ...well ...nothing says you cannot try a few different tires. But, 99% of you will not invest the $ to do short mileage testing/sale/buy/test.
12. MOST 'modern' tires on the OLDEST Airheads (perhaps to as late as 1985) require considerably higher pressures than stated on the tag under the seat or in the owner's manual or in some tire manufacturer's literature. BMW did better by the late eighties onward regarding tire pressure recommendations. Failure to inflate to proper higher values will result in poor handling; the bike may feel like the tires are trying to roll off the rim, etc. When you DO inflate to a higher value, the tire MIGHT feel skittery, until you are used to the improved handling. The reverse is seen now and then...that is....SOME STILL BELIEVE THE TIRE PRESSURE LISTED ON A TIRE SIDEWALL IS THE RECOMMENDED TIRE PRESSURE. IT IS NOT. IT IS A MAXIMUM TIRE PRESSURE, BASED ON WHATEVER STANDARDS THE MANUFACTURER USES FOR THE CARCASS, and other things, such as CONSTRUCTION & pressures versus industry classifications. I treat tire pressures a bit more in-depth in http://bmwmotorcycletech.info/TireRepair.htm in a section near the bottom of that article. FOR YEARS I have been telling people that the tire pressures printed in your owners booklet, & in various literature, & particularly so for BMW's prior-to-1985 models (after which tire pressure recommendations are a more reasonable but not perfect, in MY opinion), are MUCH TOO LOW....for modern tires.
Below is a link to a page with charts of recommended tire pressures. I ran across this information in November, 2014. I mostly agree with the page. YOUR tire size may not be listed, probably isn't, but you can interpolate & assess/guess. This is one of the very few tire pressure guidelines that is generic; & does not have lawyers telling the tire makers to recommend only what BMW (or other mfr) says in their literature WHICH PROBABLY IS NOT CORRECT FOR THE TIRE MAKER'S TIRES! I wish Avonmoto had published for many more sizes. You might notice, even with a quick glance, that the guidelines don't have anything much or overly-specific to say about TYPES of tires. That's because differences, unless for specialized purposes, are NOT ALL THAT PERTINENT. You may notice that tire pressures are recommended that might be higher than in other tire makers literature, particularly if they use BRAND names for bikes. That's another way of saying that lawyers have too much influence on many tire makers! NOTE that the first listings are for BOTH bias and radial tires! http://www.avonmoto.com/tech/tire-pressure-guidelines
13. When the rear tire 'squares-off'; & some do this rather faster than others (dual-compound tires are better at not squaring off fast), handling can be poor in curves, particularly fast changing twisties. INstability (wobbles) can be very apparent with a squared rear tire, if such problems happen. See: http://bmwmotorcycletech.info/instability.htm. Some types of instabilities can be HIGHLY dangerous & not just annoying. In some instances, when combined with, perhaps, an improperly adjusted steering head
preload; & maybe, OR NOT, other things, such as saddlebags, backrest, windscreen...etc. ...you can SUDDENLY get a very bad wobble, at high speeds. YES, I did just say that squared-off REAR tires can cause high speed wobbles! That has been extensively PROVEN & you need not take my word for this!
Tires by brand, model, & description of performance:
(1) A TUBELESS tire that does NOT use steel strands in the tread is much more likely to have a LASTING on-road repair, by using sticky strings or internal patch. This is particularly so if you are using such as the Stop'nGo mushroom type of plugs, which require a lot of reaming on tread area puncture holes on steel ply tires. The Avon Roadriders, as ONE example, do NOT have steel plies. Conversely, that makes them POSSIBLY more conducive to punctures. All this is strictly speculation! I am not knocking Stop'nGo, I carry their plugger kit with me! I MAY run some puncture tests on tires if I live long enough!
(2) If using metric tires, use the 90-90 or 100-90 front if using 19 inch. Pre-1977 bikes need a wider fender mount for the wider 100-90 tire, 46-61-1-234-907, this is common to all brands for that size. I strongly suggest if using metric sizes on your early TWIN-SHOCK
Airhead that you use 110/90-18 rear, and NOT a 120/90-18 rear...it is not generally recommended by me for twin rear shocks Airheads models, specially the rear drum brake models with cast wheels (Snowflake).
The "everything else" section follows the tires by brand name section.
Bottom line: good tire (cracking aside). I prefer the Michelin Pilot Activ; and I haven't any experience on the new Continental Classic Attack's ... yet. DO I think the Avon Roadrider's are worth the cost, which is somewhat LOWER than the Pilot Activ, etc. ...but the tread cracking is to be considered. For years, as noted below, the Bridgestone S-11 (Spitfire) tires were ones I used for comparisons. I think they FEEL considerably more stable than the Avon RoadRider; even on rain grooves. I still like the S-11 & perhaps prefer them for a high percentage of street riders .... all things considered (price, performance, mileage, handling and feel). AGAIN: The cracking is a potentially serious problem.
I am tentatively putting a NOT RECOMMENDED rating on these tires, primarily for cracking & possibly short life ....and this has been reported by others too.
GRIPSTER AM24: For Dual-sport riders. Has been around for a LONG TIME & it is a well-proven tire; fairly good street tire if a bit noisy, sticks WELL in cornering, quite stable & not bad in rain either. Works pretty good in off-road gravel & hard pack, fair/poor in mud, & are, perhaps, a bit rough/hard feeling. I suggest using about 31 psi front & 35 psi rear for all-around use. These are possibly not quite as good as the Michelin Anakee for street and dirt. The Continental TKC 80 is better than the Avon AM24 off-road.
DISTANZIA AM43/AM44: Is much more of a street tire, decent in the rain, only fair off-road, but fine for the street rider who ventures off the road on occasion.
NEITHER of these Avon tires would be my choice for a bit deeper or rougher off-road dual-sport work. Both the Gripster & Distanzia are primarily paved road tires, with modest to OK off-road capability, the Distanzia having the edge for the street & life, at maybe 1/3rd more cost. The Gripster is a quite decent tire for the person who is primarily a paved-road-rider, yet ventures off the road now & then, who may even be a bit aggressive off-road. The AM24 is a GOOD all-around tire & works well in anything but mud; keep in mind that usually only VERY aggressive tires work in mud. See the Continental TKC80, below.
TKC70: More paved-road than off-road. Probably similar to the Metzeler Tourance, over-all. If your riding is more off-road than paved, try the TKC80. I have personally not ridden on the TKC70.
TKC 80: This tire has been around for some time. It is for dual-sport use & good on pavement besides off-road. OK even in rather aggressive riding, although feels a bit squirrely to me, even considering the tread. Limited sizes available? Grips OK on pavement, on sand & gravel, dirt, even reasonable on mud! A GOOD choice for those going off-road more often....yet retains good performance on the street, FAIR/OK when wet, even "OK" on snow. One of my favorite all-around dual-sport tires. It, perhaps surprisingly, corners good. Does not last as long as the Metzeler Tourance. This is not a great mileage tire for mixed use...but was surely worth it for heavy adventure bikes, like the BMW GS line. Tossup as to whether you'd like it over the Avon AM24 Gripsters, but I DO. The TKC 80 is fairly quiet, inspires confidence in how it FEELS. I think MOST riders, no matter the model of BMW, will like this tire, even if you are a street rider but do maybe half your riding truly off-road. If you want all-around performance in a tire that will be 'capable of any surface', even some mud, THIS IS THE ONE. Original equipment on some BMW models. If you like the TKC80, you might also want to try the TrailAttack. You also may want to look at what I say about the Kenda K784. I have NO experience on the TrailAttack, & welcome comments. For sure, try the Avon AM24 Gripster, to compare to the Continental TKC 80. You might prefer the Michelin Anakee-Wild tire.
Drawbacks: Expensive. Tread too aggressive for "mostly" street riding. Tread blocks wear weirdly sometimes.
RB2/K112 (also TK22): Original types used on the OLDEST Airheads as ORIGINAL equipment. I have not ridden on any in many years; I always disliked the way they followed rain grooves...but they do...or at least did....offer the classic BMW soft ride, last pretty good used with original 'high-speeds, two-up' tire pressure settings. I might try testing some of the new modern versions as I have heard the rubber compound is improved since Continental re-started production some time ago on these. I won't use my own bike. Owners of early Airheads that came with the 3.25-19 front & 4.00-18 rear tires as stock sizes, should try a set of these Continental tires if they want the classic ride AND LOOK. You won't get that classic ride if you have a modified suspension. The originals were "OK" but not for true performance riders, especially if you are fairly aggressive, and considering the newer designs available now. Note: I don't purchase Continental tires myself due to how they treated my shop when Continental had a bad batch of tires, decades ago. But, I do NOT, in the slightest, want to discourage YOU from trying these tires, as you may love them. If you intend to ride on classic tires, I also suggest the Metzeler tires like the ME11, etc. Accolade tires?? BMW installed Metzelers in the old models/sizes, besides Continental's.
This is the Continental RB2 (front):
Classic Attack Radial (Conti Attack Classic Radial): This is a new design from Continental. Continental says that they specifically designed this tire, A RADIAL 0° type, to enhance & sharpen the handling of older classic bikes which were originally designed for bias-ply tires. I have not yet tested these tires. From a look at the tread pattern, I think the tires MIGHT NOT track rain grooves, & should feel fine. The tire is supposedly fairly high mileage with excellent grip & fast break-in. The V-rated tire is available only in metric sizes (??). The 100/90R19 57V TL, a front tire, is expensive, although discounts may be available. That tire, like all of that size, will probably not fit earliest Airheads without the proper later fender brace, 46-61-1-234-907 from the 1977-1980 /7 series. Probably will need the later fender too. The other usable metric sizes are a 90/90 in 18 inch size for later airheads, and available is also a 110/90R18 61V TL & 120/90R18 5 65V TL, these two are designed for rear use. The 110 is likely the BETTER choice over the 120. NOTE the load rating on these tires, compare to your previous and other tires. Tubeless construction. If used with tubes, you should reduce the speed rating by one step. That's FINE for Airheads, who hardly usually need more than an H rating, let alone an S or V. Some riders who have tried these LOVE THEM. As noted, no personal testing information yet. Tom Cutter reported that these type tires were easy to R/R, provided a comfortable ride, were stable, and had a nice feeling. ... somewhat expensive. Other sizes may become available. I am looking forward to comparing these tires to Michelin Pilot Active & Avon RoadRider.
Metzeler: (see Continental, RB2/K112, for comments regarding the Metzeler ME11, and Heritage tires)
Lasertec: I do not like this tire ...NOT for the less-aggressive rider. It is twitchy, gives an unstable feeling. Aggressive riders might want to try it. This tire does NOT feel like the ME33 Laser to me. The tires have been reported as inconsistent in manufacture. That may be so. They tend to follow rain grooves....likely due to its single circumference groove (or multiple wiggle type) groove(s) in the center of the tire. If you don't have grooved highways, or don't mind the (not awful) instability, then you MIGHT like this tire. I was surprised by the twitchiness, & while different, I compared its twitchy feeling to the Avon RoadRider. The twitchiness may be partly a "less-rubber-on-the-road" FEELING. I did NOT do tire pressure testing. NOTE that a lot of the more
modern tires have some very light handling qualities, which I call twitchiness. It DOES stick "OK", corners nicely; gives "some" confidence in tight twisties. This tire should match up with many of Metzeler's other tires. I just did not like the tire much.
ME55: An old favorite for some. I never liked this tire much, although it gave a good compromise on handling & mileage.
ME88: Front & rear versions. A mileage tire, reasonably good handling; one of my old favorites for use front & rear for TOURING. Interestingly, this tire also worked well as a rear with ME 33 Laser front, for more aggressive paved road riders. I have tested ONLY those made in Germany. AFAIK, discontinued...unfortunately.
ME880: NO personal tests yet; no trustworthy reports yet either.
Tourance: OK on the street, "fair" on gravel and hard-pack dirt. The Michelin Anakee is probably better all-around, by a bit, wet and dry, for dual-sport. The Continental TKC70 is roughly the same, performance-wise, as the Tourance. Tourances are NOT good in any sort of mud.
Enduro tires: Metzeler has a selection of these tube type tires to fit older airheads. The Enduro 3 (Sahara or Sahara 3) is a good one for mixed on-off road. It is premium priced, however. Watch the WIDTH....Enduro tires may be MUCH wider than their size might lead you to believe; thus may not fit on twin-shock models, due to swing arm
problems. I use to use the Sahara 3 for my rear tire on the sidecar rig in the Winter; mainly because I got some cheaply. Nearly every motorcycle tire manufacturer has its own enduro tires.
MCE Karoo: These are good GS type tires for off-road, fairly decent on pavement. I suggest you don't mix other types on the same bike. For pavement use, especially if the weather is cold, let them warm up before getting aggressive with them. Many equate these tires with the Continental TKC80, I think them only somewhat similar. There is now a Karoo 3...no information nor testing by me.
BTW...I had a miserable time trying to mount the Pilot Activ 4.00H18 to the 84 R100RT rear snowflake wheel. One side went to the rim bead area OK, the other VERY difficult. I am NOT the only person to have this problem. Because of this, I modified my air equipment AGAIN, & then it went on OK, withOUT excessive pressure too. I found it critical for the rim/bead area to be VERY smooth, I even polished it...& used LOTS of real tire lube. I added the new inflating information, primarily an opening-up of the chuck, removing the valve in the tube, etc., reason: to increase FLOW RATE. See:
http://bmwmotorcycletech.info/tirerepair.htm. This tire is very stiff in the sidewalls, even the tread. Do not be discouraged by these
remarks. This tire has a very well-made bead edge, which should offer better sealing
on a tubeless rim than many others...but a tubeless rim & a tube type rim do NOT have the same shape for the bead area...the angle can be 9° different in some cases. For those who use a tube type rim as tubeless, I think this tire will do better than many others in the instance of an air leak or flat. This is speculation on my part. Such usage is not recommended by many. There IS an article on this website about such usage.
Standard Michelin Butyl tire tubes for my testing.
Anakee3: The Anakee 3 is different from the Anakee 2. The 3 is for mixed on and off road, seems pretty good all-around until you get into mud, where it's poor. Emphasis is on pavement riding. EXPENSIVE. May be difficult to mount? Competition for these tires are the Continental Trail Attack, the Avon Distanzia, and Metzeler's Tourance. In general, the Anakee line of tires is competent. I have not had a chance to try the Anakee-Wild; only seen reports on these radials. Some think these are THE best on/off road tires available...with good mileage too. But, they make noise. The rear tire on these seems unique in tread design, and seems to work well.
T-63: For more aggressive off-road riders, handle decently on dry pavement (not too bad on wet roads either); probably one of the best buys for mixed use (dual-sport, with a fair amount of emphasis towards off-road). The T63 is a good tire. A trusted friend told me about this tire, & how he, on a bike loaded with luggage & his girlfriend on the rear of the seat, practically melted the tire from very high speeds, in Arizona, in exceptionally hot weather on a very hot black asphalt road. I went out of my way to test this tire on someone's bike. It is less expensive than much of its competition. This tire has a moderately aggressive enduro tread, so unless you do some off-roading, don't get it. This is NOT the tire for quite heavy loads at quite high speeds, coupled with very hot asphalt. In fact, I can't recommend any Enduro or knobby tire for that. I have ridden ~ 78 miles on an Airhead equipped with these. My opinion matches someone else's, who rides aggressively. While the tread does look aggressive, the tire is somewhat milder than it looks. I do not know about expected mileage life, but I think the tire worth the modest cost.
Pilot Road 2: Seem to be excellent on Classic K-bikes...very limited experience here.
OVER-ALL, I am IMPRESSED with the Michelin brand of tires. Even for my SUV.
The "everything else" section of this long article:
1. Some folks have trouble understanding tires sizes. On metric tires the first number is the width in mm on a nominal width rim, the second number is the aspect ratio of the sidewall to tire height. Metric sizes and inch sizes
are not exact equivalents. GENERALLY speaking a 3.25 inch size as originally specified can be substituted by a 90 metric (often coded as MJ); a 3.50" by a 100 metric (MM); a 3.75 or 4.00 by a 110 metric (MN or MP); and a 4.25 or 4.50 by a 120 (or MR).
There WILL BE handling differences if you do not use the originally specified size of tires. Those that have heavy loads may want ONE size oversize tires. It may behoove you to look into the load carrying capability of your proposed new tires...usually molded/printed on the sidewall. SOMEtimes a larger tire is rated for a LOWER load. Using a stock rear tire, let us say 4.00-18, with a substantially oversize front tire, is not the best combination, as the bike will PROBABLY have a tendency to fall into turns a bit; but I have NOT found that too excessive if not going too big. As I noted; sometimes an oversize tire will have LESS load capacity, and you MAY have to look at the manufacturer's technical data to find this out.
IN GENERAL: OK for a 3.25 front to be 3.50 or 90/90 or 100/90; and, OK for a 4.00 rear to be 110 or 120. There is a 4.10 size that MIGHT work, but I have NO DATA, NO EXPERIENCE. I also have very limited information on using 80 profile tires. Aspect ratios of 80% will NOT always work on early Airheads. It is often a matter of the sidewall width. not just other fitment problems. The fitting problem is almost always only with the twin rear shock models, due to swing arm clearance, and also sometimes with disc brake stay arm interference. Both are usually easy to deal with. Most of the early Airheads came with inch size tires: 3.25 x 19 inch front tire and 4.00 x 18 inch rear tire. For some time, in the recent past, FEW tires were made in those sizes, but availability has considerably improved. In general, these old sizes were in what, today, is called a 90 profile. Some were closer to an 80 series. NOTE that the old Airheads (except G/S) did not come with enduro tires, and I mention this because most enduro tires in 4.00 x 18 will be VASTLY wider than a 4.00 x 18 paved road type of tire. An enduro tire may well NOT fit on twin shock Airheads, not enough room between tire and driveshaft housing. This is particularly so on those before 1981. These can have a wider right side of rear wheel spacer installed, and BMW even sells such, but that may not help enough. Very early Airheads could even have fitment problems with 110 size in the rear. In some instances SOME 120 will fit the later rear; BUT, sometimes (pre-1981 for instance) one has to get the wider 10.7 mm spacer for the right side of the rear hub...BMW part number 36-31-2-301-737. That spacer change has been needed sometimes for 110, but not often; more often for 120 (even for early eighties twin shock models). Stock was 9.2 mm, and was 36-31-4-038-142. The spacers are VERY easy to install, and do NOT affect bearing preload. A few 120 rear tires fit rather tightly on drum brake models; that is, the wheel with tire mounted to it is a bit difficult to install, and deflating it is needed. NOTE: BMW uses 'top hat spacers', or call them brimmed spacers, at various places in the bikes. You will find them at the swing arm sides, and the wheels. One top hat spacer, 36-31-230-322, 12.9 mm wide, 32 mm hat, has been sometimes used to space the rear wheel to the left even more than the 10.7 BMW sells specifically for that purpose. That spacer is 12.9 mm wide, and the hat is nearly 32 mm in diameter.
For the front tire, which came as a 3.25 x 19 (and in some cases, like the R65, 18"), you can usually go to 3.50 x 19 or metric 100/90, but you might have to use a later seventies fender mount. More much later in this article on that. A 90/90 or even 100/90 on the front, and a 110/90 on the rear is very common and USUALLY WORKS WELL on Airheads.
The part number used by BMW for some of the top hat spacers at the swing arm bearings is different than the almost exactly the same 9.2 mm part used at the wheel bearings. They are usable however!
BMW modified the REAR WIRE SPOKED wheels for extra clearance, and this was done in the /5 days, as well as the ST and G/S days, and it was done by offsetting the spokes; details elsewhere's on this site. While many think that the ST and G/S 3 mm offset change came when the REAR wheel went to a 2.50 from a 1.85 size, this is not so, it was later on ...after that change.
2. The rear fender can be modified, hardly shows, makes tire changes easier. htttp://bmwmotorcycletech.info/RearFenderMod.jpg for a photo.
3. The BMW tube-type snowflake wheels are "WM2" in rim SHAPE. Other articles of mine treat the use of tubeless tires withOUT tubes. Click here for that link, http://bmwmotorcycletech.info/section6.htm. It is almost always OK to install a tubeless tire WITH tube into a tubeless wheel...but mentally reduce the speed rating by one grade, due to heat buildup with a tube.
4. Try not to purchase tires more than THREE years old, date codes are on the sidewall, showing week of the year & the year.
5. The maximum inflation pressure shown on the sidewall is for normal use, not for inflation to seat a bead, which is higher, just how much higher is subject to safety concerns. For installing tires I don't go over 60 psi, try to stay at 50 psi, and use lots of REAL tire lube. Generally the manufacturers will allow up to 50% over the sidewall printing for mounting....be cautious, if a rim explodes you can be seriously injured. THE secrets to seating a tire are to have the rim edge and bead area CLEAN and VERY SMOOTH, use LOTS oREAL tire lube and have the tire and wheel (and tube if used ) truly hot from being in the sun! REMOVE THE VALVE CORE ....AND ALSO REMOVE THE TIP IN THE air compressor's HOSE CHUCK. USE A 125+ PSI 3 GALLON+ TANK ON THE COMPRESSOR & large inner bore size fittings & hose. Be ready to quickly open any valve in the compressor-to-tire circuit. ALL THIS SO THE INRUSH OF AIR IS FAST. YES, the SPEED of the air inflation is a BIG secret! Even so, an occasional tire will prove to be difficult.
6. NEW tires are VERY slippery!.....allow 20-50 miles to scrub them off. I prefer to first thoroughly brush the tires with a fairly strong detergent and hot water mixture, and then flush them, before riding on them. I use a stiff bristled old-fashioned floor scrubbing brush.
7. Continuous speed rating is marked on the tire, usually as part of the number/letters of the tire size. Tires with deeper tread from the same manufacturer and same model of tire MAY wear longer, sometimes they do not. Deeper tread tires are generally rated lower in speed, and usually are the better buy for touring. If you do not ride at warp speeds, an H rated tire may be a much better buy than a V rated, as an example. MAY is the word here. Sometimes the only difference is TREAD depth....the higher rated tire having a LESS deep tread. This is not universally so. Another way of stating this, a bit differently, is that a higher rated tire is NOT AT ALL necessarily a better tire...for YOU!
Here is a chart of what the letters mean. Remember, if you install a tube in a tire marked tubeless, reduce a grade. That is easy to see on the chart except for the H rated tire. If tubeless, and used with a tube, downgrade to S. Motorcycle tires have had for some time a LOAD index coding, something like 81H. The tires may eventually get the standard car tire coding of alphabet letters for wear and heat. If you pack heavily, perhaps you weigh a lot, and you have a passenger.....pay attention to the manufacturer's published information on loading allowed. TL means tubeless....does NOT mean you MUST run it tubeless. - means bias ply. R means radial; B means bias belted. A FEW tires marked tubeless should not be used with tubes. Ask, and look at the sidewall printing too.
Z & ZR
Some V, VR,
may be rated
over 149 Mph.
(W) is rated over 168 mph.
8. Tire direction:
Sometimes both motorcycle riders & sidecarists will use a tire designed for rear use, on the front. Some tires are bi-directional, & maybe with two markings for direction, depending on if used for front or rear.
For sidecarists, 16 inch rims CAN be used for passenger car tires OR motorcycle tires (if rim width and area to the safety bead, if any, is proper). Do NOT generally use or try to install, a 15 inch m/c tire on a 15 inch car rim, nor 15 inch car tire on a 15 inch motorcycle rated rim. You MAY be able to use a 15" car tire if the motorcycle rim is skimmed on a lathe or the car tire is a quite small one. ***PLEASE HEED THESE WARNINGS, and here is why:
15 inch car tires and 15 inch motorcycle rims are NOT the same diameter! 16 and 17 inch seem OK. If you insist on putting a 15" car tire onto a 15" motorcycle wheel, the smallest tires may work OK, the larger ones are definitely dangerous. YOU CAN HAVE A CATASTROPHIC FAILURE! Some sidecar manufacturer's use 15" car type rims. NOTE that tire rim bead area is wider, from inside rim edge to the safety bead (if any), for CAR wheels. This can create safety problems......
If you are using any combination of car rim with motorcycle tire, or motorcycle tire with car rim, there are some nerdy details you need to know; this link is a long read, but has some pearls of wisdom regarding use of those combinations: http://www.goldwingfacts.com/forums/10-reference-faq-forum/400426-design-differences-between-car-motorcycle-rim-tire.html
9. There ARE reasons to NOT screw the tube valve stem nut
to the OUTSIDE of the rim:
No allowance for tube movement with a leak & if the tire rotates on the rim some. If the tube seals to the rim too well, it can trap air from tube to rim, allowing tube chafing. Purpose of the tube nut is to help DURING installation of the tube, I can be discarded, or run up to the cap, after the mounting is done. These ARE NOT just my ideas! I can quote from tire manufacturer's manuals & a BMW bulletin on these facts! BMW has bulletins on these valve nuts, & one SI gave an additional reason to have it up against the cap, that was that improper inflation could cause the tube to be weakened at the valve stem & if the nut was at the rim & not the cap, the stem could disastrously tear out, suddenly. What BMW did not say, was that this comes from very low inflation AND over-inflation during seating of the tire.
My tire repair article: http://bmwmotorcycletech.info/tirerepair.htm has a lot more information on using the nuts, concave washers, valve insertion tools, etc.
10. Inflation is usually in psi (pounds per square inch), but some tires have it in BARS. Bar means BARometric pressure, one Bar is atmospheric pressure, ~ 15 psi. Manufacturer's, such as Metzeler, used to have (in their technical engineering books), information, that during mounting, the maximum inflation pressure (DO use plenty of tire lube!!) was 150% of the tire sidewall printed value. Manufacturer's are getting increasingly lawsuit conscious for products sold in the USA...and many now say not to exceed the sidewall printed value, or 20% or some such. Because 150% can be interpreted by some to be 150% on top of the original pressure, some manufacturer's changed wording to say 50% increase over maximum sidewall-printed pressure. You are on your own. I do not go over 50 psi unless I am forced to, and it is very rare indeed that I go to 60 psi on a motorcycle type tire. This is NOT an OK for YOU to do that! An exploding rim can kill you. However, I believe 50% over the maximum pressure as molded into the sidewall of the tire is SAFE (assuming a good rim). Seating of modern stiff sidewall-bead area tires onto the rim is usually THE problem seen. Prepare the rim by cleaning the rim, and if it is not VERY smooth, on the outer edge, and the side area, sandpaper it. USE LOTS OF TIRE LUBE on the bead area of the rim and the tire bead area. Have the tube and tire hot from being in sunlight for a considerable time, almost too hot to touch with bare hands is nice. MIND the previous hints about using a modified chuck, no valve in the valve stem, & lots of lubricant.....this really really does work well. read: http://bmwmotorcycletech.info/tirerepair.htm.... completely.
An old "Rule of Thumb" says that after a considerable number of miles, the cold temperature pressure in a tire should have risen to ~8% higher with the tire is hot. That is generally true, but not all types of tires seem to conform, particularly some belted & radial types. Still, it can be a useful idea. Where this idea came from is actually the manufacturers of tires. If the pressure is too low, the tire will flex more, creating more heat; if pressure is too high, the tire will not heat enough. Proper tire temperature enables the tire to work as designed. Tires require the correct pressure for handling & life, etc. Sometimes someone will ask me about tire temperature. Road tires are designed to run at ~130°C at the contact point. That is VERY HOT. That was NOT a typo, it IS degrees Centigrade. That contact point cools off VERY rapidly when you come to a stop, so you can pretty much forget about trying to measure it; particularly with a non-contact meter, that many seem to own, that does not respond well/accurately to black tires. A real nerd would get the temperature from the manufacturer, and affix a special temperature meter to the bike, and STILL not get accurate information!
Many TIRE manufacturer's used to tell you the REAL tire pressure to use or try with their tires. Lawyers probably got involved. Most literature now just shows the motorcycle manufacturer's recommendation......which may be too low for old Airheads and modern tires. Generally BMW recommendations are pretty much correct on the single sided rear end Airheads (with some caution for the ST and G/S) & usually any BMW motorcycle from ~1985...and NOT correct, seriously not, for modern tires on pre-1985. BMW had recommended tire pressures on a label someplace under the seat & in the owner's manual. Some later BMW literature upped some of the old pressures to SOLO 32-34 psi, both front & rear. That pressure is STILL LIKELY NOT correct for YOUR riding, tires, conditions. I have found almost NO tires that should have 32 psi in the rear! Modern tires NEED higher pressures: 33-36 front; 38-42 rear.
11. Airheads came with a number of different rim WIDTHS and TWO GENERAL SHAPES, & one special shape. BMW used the WM2 rim up until they installed tubeless tires, not officially OK with tubeless tires withOUT tubes. Many arguments abound about this subject. The WM2 rim does NOT have the 5 degree increased angle of the flat area inside and the side area...all of which the tire bead rest against. You are ON YOUR OWN if you fit without a tube, in a snowflake wheel designed for tubes. Rim width and tire size fitted must be within a range of values in order to not only fit into the fender/brace/etc; and swing arm on the twin shock models. If a tire is considerably too wide for the rim, the tire will tend to roll in turns, making for lousy handling.
EVERY tire manufacturer has a recommended range of rim sizes for each model
and size of tire. Those recommendations ARE correct. Early /5 rims were 1.85" on front AND rear. Later /5 bikes had 2.15" rear rims. The 1.85" front rim was carried along right up to 1984 on most models. The R80G/S had the narrow 1.85 front rim, and early ones the 2.15 rear, then came a 2.50 rear. The R80 G/S had a 21" front wheel. Some of the bikes came with a 2.75" rear rim...this was on the 1978-84 RS, R100S; and 79-84 RT with disc brake rears; the drum brake rear bikes in these groups were generally 2.50". With the Monolever and Paralever bikes, things changed with the rims again, with a new rim design, for tubeless tires withOUT tubes, etc. An EXTENSIVE article on using various rims as tubeless, etc., is HERE:
12. Some have a hard time getting a pressure gauge onto the valve stems of the snowflake rims. There is a 90 degree stem adapter available from BMW, I don't recommend its permanent use though. FRANKLY I don't use them at any time. 71-11-1-239-258. Any of the stock type, 45 or 90 degree head pressure gauges are fine....Consider checking their calibration once in awhile.
For other purposes than difficulty with using a gauge, BMW also has a steel, chromed, straight valve stem, for use with tubeless (and for snowflake conversions, but this is NOT officially approved), it is about $4 from BMW...and is available elsewhere's cheaper. You cannot get a good seal with the stem, unless the inside of the rim has a flat milled place for that valve stem. The BMW number is 36-32-1-452-748...and this part is vastly nicer than a typical small car or yard vehicle all rubber stem.
13. Most flats/punctures are on rear tires. MANY can be avoided....by simply putting a wide and fairly LONG mudflap onto the FRONT fender, the closer to the ground the better. Nice looking ones are available. You may have to drill some holes, use screws, washers, nuts. What this flap HELPS to do (theory anyway) is to deflect road garbage that would otherwise being thrown backwards, perhaps standing the debris upright.....and into the path of the rear tire. Hence, the type that hangs down the furthest is desirable. The truth is a mixture of that, and the fact that the REAR tire provides the tread-distortion of acceleration and engine braking and thus has much higher contact forces with anything on the road.
14. Tire markings:
Tire sidewalls have a lot of information. One area shows the manufacturing DATE. On earlier tires, prior to year 2000, there were THREE digits... first two digits meaning the WEEK of the year, and a third digit for the year. In the 1990's, there was a small triangle to identify that it was made in the 1990's. Sometime during the 2000 year all manufacturer's changed to the 4 digit system, the first two digits being the WEEK of the year, and the last two digits being the YEAR. If the tire code was 0455 or 455, you know the tire was manufactured in the 45th week of a year ending in 5 (but it had to be 1995, if the triangle preceded). The reason only three digits was originally used was that the bureaucrats thought that tires would not likely be in service for over 10 years.
There is additional coding you may be interested in. There will be something like this: DOT ENYO VLK 1704. What you MAY be interested in is the two letters after DOT, in this example, EN. These can be looked up at http://www.harriger.com to find out what factory (China?) they were made in. I have PURPOSELY not listed the exact URL for the specific PAGE in that website, as INTERNAL links do not properly relate to outside full URL's.
There is a longer DOT code in use now. The DOT coding begins by some letters and numbers. The first two letters identify the factory. The list is at:
www.harriger.com/tiremakers.htm. The last 4 digits are the week and year, as before. NOTE that while DOT regulations mandate information on both sides of the sidewalls, you may have to look in two places and on both sides for the ENTIRE identification numbers/letters. The original reason this was done was, supposedly, to reduce problems with the
manufacturing and mold interference.
15. Recommended and NOT recommended tire vendors. This section is not kept-up to-date.
a. NOT recommended: MAW (www.mawonline.com, Motorcycle Accessory Warehouse).
: Discount motorcycle tire and accessories.
b. Below, OK; but pay attention to shipping charges, sometimes if you buy TWO tires shipping is free. Pay attention to date codes.
Motorcycle Superstore, Medford, Oregon. Cheaper if order is over $89, free shipping.
SW mototires (no shipping charge if buying two)
Generally, BikeBandit has decent prices and decent cost for shipping. AMA members get 10% additional discount.
c. Don't forget to do a thorough Internet search; and, do NOT forget about your local independent BMW servicer ....and even your BMW dealership.
There is BAD information, or just plain hype, on the use of nitrogen in any type of tire for road & off-road use. The facts are, that while there ARE benefits, use of nitrogen to fill tires is USUALLY NOT all that practical for anything but racing, as far as MOTORCYCLES are concerned.
On the plus side, molecules of nitrogen are said to be larger than average air molecules. These larger molecules do NOT pass through the rubber used in tires and tubes quite as easily as common air molecules. Thus, pressure loss over time is lower, this is particularly so with higher percentage natural rubber tubes, as opposed to the lower percentage natural rubber, often just called plastic tubes. On a practical basis, the slower loss is REALLY NOT a BIG difference. One factor not discussed is the over-all 'thickness' of air, not just oxygen as often spoken about with regards to nitrogen use. Average atmospheric air is 78% nitrogen, 21% oxygen, then comes water molecules, carbon dioxide (CO2), and rare gases. Thus, the oxygen often talked about is actually only about a fourth of what the nitrogen is....so the oxygen has even less effect than nerdy so-called scientific papers you may find on the internet, regarding tire pressure loss over time, ETC. Another factor is that nitrogen is sold in pressurized metal containers, similar to welding containers, and the nitrogen can be relatively dry and pure....or, rather not-so. If using nitrogen to fill tires, from empty (just residual air), the highest percentage of dry nitrogen would obviously be best. CostCo, which does NOT sell motorcycle tires, DOES use the premium nitrogen.
A plus factor for nitrogen is that it is less prone to accumulate water vapor and is usually very DRY when installed into the tire, not so the 'outside air' from your average compressor setup, nor a gas station. Water vapor in common compressed air can lead to rather wild fluctuations in pressure as the tire heats up & cools down. Obviously, this is minimized by using clean, dry, air. Nitrogen, due to its lack of extra affinity for water vapor, delivers a safer, more stable tire pressure, which can be somewhat important for very high speed driving (more so at racing speeds). The final good point about nitrogen is that it does not contain oxygen, which tends to degrade rubber compounds over long periods of time. The PROBLEM with nitrogen is cost, not easily available, and if you top off the tire with too much compressed air, especially if the air is not dry, some advantages of the nitrogen is LOST. This is LESS SO, if the nitrogen that was used is a very high percentage type, and you add little air. Nitrogen's good effects work with tubeless AND tubes. If you are interested in a nerdy technical scientific answer to nitrogen versus oxygen in tires and tubes, go HERE:
When you have assimilated that, above, how about a more practical approach?... easy to read, and basically correct, and fills in some things you did NOT get from the above link: http://www.pedrosgarage.com/Site_5/Nitrogen_or_Air.html
NEITHER of those two articles covers what I have, in the above paragraphs. NEITHER tells the full story, and I have.
17. There are instances wherein someone uses a tube-rated tire without a tube. In some instances this is done with various motorcycle tires, but also done with two special sidecar type tires.... and, there are only TWO types of these square-profile sidecar tires available, as far as I know. One in 18" and one in 19", and not from the same manufacturer. The 19" is from Avon and called the Triple Duty; the 18" is from Metzeler and called the Block K. I have tried nitrogen in these tires, and it appears that tire pressure loss IS SLOWER. Since the pressure loss from these particular two tires CAN be more rapid than with tires using tubes, this is something to consider.
Another usage is a tubeless tire used on tube-rated rims. That brings up a whole story in itself, and has its own article on this website: http://bmwmotorcycletech.info/section6.htm. I have done preliminary testing; leakage does seem less with nitrogen. The bottom line, of course, is that few of you are going to buy or lease nitrogen tanks for use at home....but some bike dealerships may be using nitrogen. I do not know if CostCo, or anyone else, has nitrogen available for motorcyclists....maybe some BMW places do..??
18. TIRE WEAR: The reasons for various "strange" tire wear & why one side of a front motorcycle tire wears so much faster than the other side...& why downshifting for braking instead of using the brakes (downshifting for braking lowers tire mileage); & a LOT more, is in the following article, which is so good that I never wrote such a complete article myself: http://www.rattlebars.com/tirewear/index.html. The only thing NOT well-explained, is why some two people with identical makes, models, & years of motorcycle, with the same make & model of motorcycle, same for the tires, & identical pressure in their tires....& the same riding habits, loading, & styles, will, or can, have such different tire wear. I'm not going to get into that, HERE, preferring to have some fun around the campfire some time.
There are several types. It does NOT have to be on water! The TWO types of hydroplaning that YOU are likely to be concerned about are called (1) Dynamic Hydroplaning; and (2) Viscous Hydroplaning. Both occur on wet roads, although the viscous type might be said to ALSO occur on ice. I'll discuss Dynamic after I discuss rubber reversion, and lastly Viscous.
You are unlikely to be much concerned with other types of hydroplaning, one of which I will mention briefly:
Maybe you have a passing interest in the fact that if the brakes are used hard enough to STOP a wheel from rotating (and you are still moving), you MIGHT heat up the rubber at the contact point to where the rubber REVERTS to its PRE-cured condition; then it just plain slides, like on ice.
Dynamic Hydroplaning, occurs when the water in front of the tire can not be moved away from the contact surface fast enough. The actual science deals with the water 'being rolled up'. That pressure is opposing the pressure the tire places on the wet surface
(the weight of the motorcycle normally on that tire contact with the surface). Various things have an effect on just when hydroplaning will occur:
Softness & other factors of the rubber compound; road surface; tire profile; type of rubber; tread depth. All those things would seem to be 'common sense'; and, yes, they are; but not to the degree you may think. NASA did a LOT of testing; their testing has since been re-proven by motorcycle & car tire manufacturers, & the results are that a major variable in dynamic hydroplaning is from the PRESSURE in the tire. Surprised? The depth of the road surface water NEED NOT be very much at all. If you are going too fast, you can and will risk hydroplaning....and complete loss of control.
Hydroplaning CAN, surprising some of you, occur with quite deep tire treads ...at a speed, in miles per hour, as low as 9.9 times the square root of the pressure in PSI. The factor for nautical miles per hour is 8.6, usually what is seen in various publications, usually not mentioning that it is nautical, NOR that this is "STATIC speed"...and no explanation). If you are MOVING, the speed is LOWER! These points are almost never in any articles about hydroplaning!
Welcome to Snowbum's anality and verboseness and propensity for providing extra facts:
Once hydroplaning starts, it can remain for MUCH lower speeds. You are in danger of suddenly loosing control, from JUST hydroplaning on a wet road, even with really good & deep tire treads on good quality tires, at fairly low speeds. If standing water is fairly thick, these speeds are much reduced, although some say there is no difference...the REASON is that they are talking about CAR tires, or reciting from literature meaning CAR tires. In any case, note that hydroplaning speed rises ...a good thing...as pressures RISE. This is exactly backwards to what some, if not most riders believe. They think that higher pressures mean less rubber on the road, more twitchy handling, etc. They think that in rain, they should LOWER the pressures. In one way, they are correct!...the bike will feel less jittery, more planted, with lower pressures.
Since the front tire is usually the critical tire, & almost always has the lowest pressure, beware of excessive speed in the wet!.....you may loose control without using the brakes & much more likely if using the brakes, even gently. Using the brakes USES UP traction. Keep in mind that hydroplaning is just one factor; you can easily loose control due to insufficient tread depth, oil on the road or floating on the water, irregularities in the road, wind from the side; a host of other factors. What all means is that you can loose control at a VERY much lower speed than that for JUST the published hydroplaning speeds.
"Viscous hydroplaning" is the type, at least on your motorcycle, that you might encounter if the road was rather smooth & the tire getting rather bald; that is, not a lot of tread is left. This can occur at very low speeds and VERY low amounts of water on the road. Less tread depth, more propensity to hydroplane.
If you are or beginning to, hydroplane, it will be like riding on ice. It is my opinion that on modern motorcycle tires if your tread depth is at least 3 or 4 mm, then the MAIN influence on the speed at which hydroplaning will occur, is the tire pressure and the thickness of the water on the road. If you never ride in the rain, you won't likely worry about hydroplaning. It is also true that there are very soft special rubber RAIN TIRES available for racing. They have special treads, and a lot more, and are NOT part of my discussion, beyond this mention.
The safest thing to do if in the rain is to reduce your speed GENTLY AND GREATLY, and be gentle with leaning and brakes. It should go without mention that you should have good tread on your tires.
For common ordinary street tires for your motorcycle, some are better than others in the rain (or, just mildly wet roads). The manufacturer's literature MAY...or may not.... be helpful in this regard. I can say the same for anecdotal 'evidence'....that is, can you believe what fellow riders say about a tire? If a LOT of your fellow riders have run the SAME tire, and nearly the same pressures, and they live in really rainy areas...well, I'd TEND to take THEIR word about the best street tires for rain....over the manufacturer's claims, or from someone who rides gently once in a great while on damp roads. Note that with many tires, a visual look-see at the tread design will tell you a lot about how the tire displaces water. You want a tread grooving design that moves the water out of the way of the tire rubber that is contacting the road. Obviously, there is a limit to what such can do for you, particularly if the water is rather high/thick, or you are going too fast.
GENERALLY speaking, the LONGEST wearing street tires are the worst for rain. BUT, this is not universally so. Some premium long-lasting street tires are quite good when it is raining.
20. Tire sizes; changing front fender brace for clearance, rear swingarm clearance, ETC:
Much of this information is also posted elsewhere's in this website. It is shown here on purpose....and expanded upon.
The original tire sizes for all the early Airheads was 3.25 x 19 front, and 4.00 x 18 rear. For those wanting to go to metric sized rubber, the 90-90/19 will fit all the 19 inch front wheels, and the 100-90/19 will fit the earliest models for the front if the fender support brace is changed to the later wider type. The later wider fender brace you would want is the 1977-1980 used on the /7 bikes. The BMW part number is 46-61-1-234-907.
For the 110 or 120 size REAR tire, problems will be with the wheel/swingarm/discbrake stay area. Most often, the 110 size fits withOUT any spacer changes. Either the 110 or the 120 will do for the rear; but I recommend you NOT get the 120, unless you have specific reasons, such as the particular selected tire is rated for a heavier load; or, you also increased the front tire size. You MIGHT have to go to the slightly wider right side top hat spacer, which is 36-31-2-301-737. Even SOME 4.00 rear tires are quite wide (especially Enduro types)! If your rear tire is touching either the swing arm or the disc brake stay at rest, or, especially likely is at high speeds, then you almost surely will have to use a wider spacer. The TOPHAT spacer I am speaking about is located in the RIGHT side of the rear wheel of twin-shock absorber bikes & is easily removed & changed. The wider spacer may not be needed on 1981 & later, but I HAVE seen it required. There is a VERY MUCH wider spacer available too, see earlier in this article.
The stock spacer is 9.2 mm wide, the 36-31-2-301-737 is 10.7 mm wide. On some bikes, with some tires, the tire will rub the swing arm at high speeds (~80+), & the spacer is a must....unless you liked the rubber smell, etc. Usually most 110 tires fit without needing the spacer, say on an early eighties RS/RT. On some rear disc brake bikes with the rear tire being a 120, I have had to ADDITIONALLY put a spacer on the left, a common very large washer called a Fender Washer, available at most hardware stores. Strangely (or not) that has mostly been when using an EARLIER snowflake wheel. These snowflakes can LOOK the same, but are NOT. That fender washer spacer moves over the brake stay very slightly...avoiding any possibility of tire rubbing at speed. The swing arms vary a bit, BMW has made several changes in the width between the arms, the sidewall depression in the right side driveshaft tube, and more width changes in the 1980-1984 era, another reason for sometimes needing the spacer(s).
When you change the right side tophat spacer to the longer (wider) one from BMW, that moves the wheel-spline-engagement very slightly to the left....by about 1.5 mm, which is a small amount. There are naysayers that think the wear on the rear splines will be such that you cannot go back, and that is not really so over the long run, nor does the tiny shortening of the spline engagement have any large bad effect on spline life. Changing the tophat spacer does NOT affect bearing preload.
The snowflake rear wheels on the RS and RT are slightly wider in rim width than the drum brake models. The disc brake snowflakes are 2.75" rim width (measured at the official point for tire contacting the rim); and the drum brake snowflake rims are 2.5". This slight 1/4" difference also makes the RS/RT disc braked bikes rear tires a bit wider...and puts a bit more rubber on the road too....and makes them a bit more suited to the 120 size tires. Rim width is stamped into the metal of the wheels at the factory.
Don't forget that the under-seat and owner's booklet values for tire pressure are TOO LOW for modern tires. Try about 33-34 psi front and 38-42 psi rear on early Airheads.
21. Bridgestone tubes are of good quality. I've had no problem with standard thickness tubes from Michelin.
22. For TUBELESS TIRES being used on TUBE TYPE RIMS, the rim hole is 8 mm. If you do not wish to enlarge the rim hole for a standard pull-in type of stem, then there is a special valve stem that is available, even from BMW, that seals at the inside of the rim by means of an O-ring built into a recess of the stem unit. The stem area of the rim, inside, must be machined flat for this to work well. It is best to do some machining on both sides for a small pull-in rubber stem.
This section was added to try to explain things often poorly understood...if at all...about such as tire
profiles, sizes, differences in construction, warming-up effects, differences between road, track,
and racing tires, etc. Some of this information came from Harriet Ridley, a moto-writer in U.K.,
but the information has been added-to, deleted, subtracted-from, edited, etc., ...by me. So, if you
see some short familiar wording or even a sentence, they might be attributed to Harriet:
Some of what you read below is very basic. READ IT ALL!
Tires work with your motorcycle to determine how hard you can brake, how fast you can accelerate and brake and how much you can lean and how well they keep you from loosing control. The tire determines much of the comfort of the motorcycle. The tire and how you use it which includes inflation amount, determines how far you can travel before they wear out and let's face it, tires aren't cheap for motorcycles. There's no optimum tire to cover every situation. Each tire is a complex trade-off between grip, longevity and handling.... and R&D is poured into finding the perfect compromise for a given situation. Three aspects are mostly responsible for a tire's characteristics - compound, carcass and profile; besides, of course, inflation pressure and road conditions including surface and temperatures; so there's a lot for engineer's to work with.
If a tire were made from pure rubber it would wear EXTREMELY quick and would never take the required weight. Instead, the 'rubber' (often a synthetic equivalent) is mixed with carbon black to make it tough and resilient, then baked at high temperatures after being mixed with what could be dozens of chemicals and even silica/sand of specific fineness. Varying quantities and types of these things determine the compound's softness and its optimum operating temperature and its wear. Many modern road tires have tire compounds that are longer lasting in the center of the tread area...that is, they have DUAL COMPOUNDS....the compound away from the center of the tread is more grippy, or has other desirable characteristics. This can make for a longer lasting tire, that handles well, in all normal conditions.
The tire grips by pushing itself against the surface so the softer the compound, the more it will grip. The softer compound will also be more abraded by the road, wear faster, as well as generate more heat by flexing more.
Regardless of compound, there's a temperature at which tires operate best for the purpose they were specifically designed for. Unless a tire reaches its optimum temperature AT THE CONTACT POINT the compound won't soften enough to provide the intended grip - hence the use of the silica in road compounds to ensure a certain level of grip in cold, damp conditions and why it is important to warm up your tires carefully before using high performance/handling/etc. Silica can also INcrease tire tread life. There is also a temperature at which all tires will overheat; and many have found that point with heavy loads, high speeds, etc. After construction a tire is cured in an oven at a certain temperature, no higher, no lower, so that everything sticks together. If your tire goes over that same temperature for too long, it will de-cure; at first it squirms and loses traction as it breaks down chemically, then it delaminates as it breaks down physically. So each tire is carefully tailored to suit its intended purpose.
TRACK-ORIENTATED: This compound is designed for plenty of grip at constant, high temperatures reached by the extreme pace maintained on a track: hard acceleration, hard braking and high corner speeds. Because it is designed to live at high temperatures the race compound will also take longer to reach its peak. That is why tire warmers are used in the pits. If you use these tires on the road and even if you ride quite hard, you'll be forced to slow down for traffic and stops, etc., and every time you do so the tires will cool off and take a long time afterwards to even approach their required temperature again. Keep this up and the tires will wear fast and shed rubber through cold tearing; so they may look like they're being used hard, but in fact they're disintegrating from misuse.
Each time a tire goes from hot to cold it IS SOMEWHAT re-curing itself to become harder, as
chemical oils used in the tread to maintain compound are released (hence, in some cases, the blue
color you sometimes see on a tire's tread after hard use). While this is minimal on a road tire, it
becomes more extreme on race compounds. Specialized race tires are designed to go through only
one heat cycle before compound deteriorates, while track-focused tires are a lot more sensitive to
heat cycles than their road equivalent. Hence tire warmers not only bring tires up to their required temperature, they also maintain a constant temperature between races or sessions to minimize heat cycles. ROAD tires are designed for all the heat cycles you might need.
CARCASS: The carcass gives the tire its required strength; it's more resilient on a road tire & how much the carcass lets the compound flex affects heat generation and its rounded shape. But because the tire's contact patch is flat the tire has to compress & distort where it meets the ground. This shape-changing means some of the rubber has to slide across the road to achieve the new shape, causing wear, while the constant flexing of compound & carcass at this point generates heat.
The old-style cross-ply tires used many layers of plies molded at an angle to give the tire strength. But the sheer amount of material used made them heavy and generate a lot of heat, so harder compounds had to be used to maintain the right temperature.
As bikes became faster, lighter and more agile, tires had to improve. Bias-belted tires appeared as
a step on the path to radial heaven, and bias belted tires are still in use on big heavy bikes where sidewall stiffness
is more important. But radials broke new ground thanks to clever layering of fabric. A radial tire is not
only lighter and more responsive, it also runs cooler as the tire distorts more easily, a special type of
distortion and angle that seems to be opposite than flexing increasing heat that I have previously
described (and with running tubes). Running cooler means you can use a softer tread for better grip with no increase in wear. The shape of the carcass's crown radius also dictates the way a tire handles, which together with the sidewall determines profile.
PROFILE: On a 120/70-17 front tire, 17 is the diameter of the wheel rim in inches, measured at a particular point of the sidewall area of the wheel; 120 is the width of the tire in millimeters, and 70 is the percentage height of the sidewall against the tire's width - so the sidewall is 84 mm tall. The higher the sidewall, the more slower steering but good stability. Lowering the sidewall by 10mm to a 120/60-17 the tire acquires a steeper profile - it is more 'triangulated'. The results are quicker steering and more grip when leaned over, but anywhere in-between straight line and transition from upright to lean angle is less stable. This explains why the multi-cylinder crotch-rockets have such wide rear tires. The carcass's crown radius also shapes the profile.
The sidewall also acts as suspension for the tire and comes in varying degrees of stiffness: a big
heavy touring tire needs the thick bead filler found in the sidewall of touring tires for added strength
and stability. By reducing the height of the sidewall, the tire is less capable of absorbing surface
irregularities and tends to hop when cranked over, causing the bike to understeer. A race
chassis with high quality suspension copes well with a quick-steering 120/60 or a racing slick's more radical profile and flexible sidewall, but fit racing slicks to a road chassis and the bike becomes un-settled. As a result road bikes and Superstock racers would generally opt for the more suitable 120/70 front tire.
Rear tire size also affects performance: a 180 section will steer quicker, while a 190 will last longer by coping better with power battering.
A road tire will greatly outperform a race tire in terms of acceleration, cornering speed, braking, durability and stability ....over the course of a road trip. You will have to do some thinking to understand that.
RADIAL TIRES: A tire's compound (tread) is molded onto the carcass. On a radial tire the carcass is typically made of two plies with strands usually of steel or aramid (that's Kevlar); the first is a radial ply that runs at 90° to the tire's rotation (folded under the steel bead), while the second runs in the direction of the tire's rotation to minimize expansion at speed. The top two plies are cross-plies (with usually Nylon strands) placed at an angle to add strength. Some new tires now becoming available for Classic Bikes (to improve handling) have different ply angles (even zero). The bead that you'll find on all types of tires holds the tire to the wheel rim with a 'rubber' bead filler to strengthen the sidewall.
• Low pressures cause tires to move around and generate heat, while high pressures will reduce the contact patch and the tire will struggle to warm up. Always check your pressures from cold (cool to baby bottle temperature). NOTE that many manufacturers, due to lawyers and thread of lawsuits, will simply repeat the motorcycle manufacturer's recommendations for street riding tire pressures; BOTH of which can be WAY wrong for YOUR tires and riding. WAY WRONG! Typically and generally, the real tire pressures you should use for street riding on OLD BIKES with modern rubber will be HIGHER than the manufacturer said for your bike when it was built. This is especially so for such as early Airheads, which used the old soft and ribbed tires, like the Continental RB2/K112. For modern tires, pressures under 30 or slightly over 30, will be QUITE WRONG for best handling...and life too! You will probably find that your bike with modern tires 33-36 front, 38-42 rear, depending on speed, aggressiveness, and loading.
• New tires need careful scrubbing in to get rid of the slippery mold release agent used at the end of the production process. Some say up to 200 miles. MY experience is that 50 miles is more than good enough, but if you scrub the tire after it is mounted and inflated, with soap and water, then flush it off, less will usually be OK. Just be particularly careful during initial 20 miles, and be sure your break-in miles include some steeper turns....head into them gently until the tires are scrubbed in! Breaking in a tire is not just scrubbing/abrasion, but the tire compound itself is breaking in, and this is hardly ever mentioned.
• A slick's uninterrupted compound (or tread) optimizes dry grip, but it's unable to clear standing water and debris. Hence a pattern is molded into a road tire's tread. A tread pattern also generates heat by flexing ('block movement') and is usually no more than 8 mm deep to prevent weave and excessive heat build-up. Mind what I have said about depth and tire rating (V, H, S...) much earlier in this article, and tire mileage.
• Race tires are available in different compounds and mix-matching can provide an ideal compromise between grip and longevity. A softer tread is used on the front for better grip while the rear gets a harder compound to cope with the power battering. The front is also sometimes fitted with a flatter, more stable profile while the rear can be more triangular for quick steering. Manufacturers do all the work for you on road tires so don't mix-match on them, unless you know what you are doing.
• Specialized race tires get different compounds on either side of the same tire, so where a track has a predominance of right-hand corners the compound will be harder on the right but softer on the left. Similarly, Bridgestone's dual-compound road tires get softer edges for good corner grip with a harder middle to reduce tires squaring off with the accumulating non-cornering miles.
• Tire wear is a complicated subject. Everyone knows that overinflation causes faster center of tread wear, and underinflation causes sloppy handling and the wear pattern moves closer to the edge. Common knowledge is that tire GRIP, LONGEVITY, and ROLLING RESISTANCE cannot all three be optimized at the same time. There is SOME truth in all these things. It is also true that tread patterns have a lot to do with clearing of water, mud, etc., and gripiness. I may add to this paragraph now and then, but one thing I want to mention is the scalloping of the tread, because so very few seem to know WHY. Some tires are more susceptible to scalloping than others. A famous instance is the Metzeler ME33 front tire. This was nearly the first V tread pattern that performed really well for paved road bikes, but some had scalloping problems....which seemed not to affect, much, actual handling, but LOOKED bad. These tires tended to scallop from weak springs, poor shocks, sometimes excessive loads for the pressure used. There was nothing basically wrong with the tires. But, because the tires could, and often did, scallop, they got a poor reputation. Funnily, the V-tread design got copied by some other makers, particularly Chinese makers. That the tires were particularly good on wet paved roads, and delivered a very prominent notification before slipping, seemed to escape the criticisms.
01/28/2004: initial 'dated' upload after final revisions.
02/03/2004: expand information on handling and tire size uses slightly
02/09/2004: add #14
09/01/2004: Update article, with better clarifications and stem part number, etc.
04/03/2005: changes in emphasis throughout, and add some hyperlinks and add #15
04/20/2005: Add tire make and model description information in more depth
05/13/2005: minor updates, primarily on the top hat spacers.
08/07/2005: add comments on karoo and scorpion and info on Discount m/c tire and acc.
08/13/2005: update section 4
09/24/2006: add 17
12/15/2009: revise & add more tire model information
05/12/2010: Revise for clarity, combine some areas, add more information to what is now 23.
05/31/2010: Add 24.
12/22/2010: #25 finally added/updated.
12/23/2010: updated tire recommendations
03/14/2011: add #26
06/20/2011: Finally got around to updating my recommendations for dual-sport tires
06/28/2011: Add more information on tire flexing, contact temperature, use with tubes
08/04/2011: Correct my math on hydroplaning, add a bit more to that info too; combine into one place.
04/25/2012: Update tire information slightly, clarify minor things here and there
06/17/2012: add Bridgestone tubes; and, update vendors
07/11/2012: Minor updates on Roadrider tires and add 28
10/14/2012: Add QR code, add language button, update Google Ad-Sense code, minor other things such as updating URL in #24. Language button removed later, as had scripting problems with it.
01/22/2013: Updated article to give more information, in depth, on tire types and uses, its own section.
04/23-24/2013: Minor updating, tire pressure reference, etc. Edit to reduce SOME duplication & improve clarity at various places.
09/20/2013: Add Conti-Attack listing & info.
10/07/2013: Add tire photos, and a few comments here and there
04/08/2014: Update the entire article. Fix typos, add information, fix numbering system, etc.
04/23/2014: Update various places. a bit more 09/25/2014
11/02/2014: Add link to #5
05/24/2015: Add note to Avon RoadRider's. Additional note regarding steel plies pros/cons, on 05/25/2015 & 06/12/2015. Testing notes on 06/19/2015 & 06/26/2015.
10/02/2015: Updated for extensive testing on Roadrider's.
11/04/2015: Updated for clarity.
11/14/2015: Heindenau review. Clean up article some, with fresh formatting, more concise statements, on 11/20/2015, & additional notes in late November. Incorporated my notes (I'd misplaced them) for my Michelin tests....found them stuffed into one of my 10,000-pockets-riding-jacket.
12/11/2015: Increase font size to 14pt, finalize changes to meta-codes, clean up due to font changes.
01/21/2016: Some updating, due to changes in comparo methods; to bring article more in line with the improved performance of the latest tires.
03/27/2016: 100% re-do the article: Update metacodes, primarily for use on small devices. Standardize and reduce use of fonts and colors. Justify left. Convert tire symbol list to a narrow table format. Eliminate numerous redundancies. Clarify some details. Add some links, including two to give the full story about nitrogen use. Miscl updates in June and July....mostly tire comments previously not included.
08/09/2016: Updated for RoadRider cracking, cautious, not-recommended, etc. Again on 09/04/2016
10/xxx/2016: Major revision in process. Metas of various types, scripts, H.L., layout, fonts, html simplifications. Expected completion date by 11/3/2016
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