RACE TIRE PRIMER

by Timothy Kast

Since it is an acknowledged fact that tires will always be the greatest variable in racing, it should always follow that every racer, and race crew member, should have a well rehearsed race tire acumen. This is usually accomplished by research, experience and paying attention, remembering of course, you are trying to avoid the SWAG method (Scientific Wild Assed Guess) in favor or a more enlightened approach. There are many myths being bandied about in racedom, so it is important to rely on reasonably knowledgeable individuals in matters of grave concern.

It is a given that there are two types of motorcycle road race tracks -- Speedways and Road Courses. A speedway is generally banked severely to allow greater cornering speeds and to provide a better show for spectators; while a road course such as Elkhart Lake, WI or Road Atlanta offer a true road race appeal in layout and construction. Speedways like Daytona or Talladega can literally eat up tires due to higher entry-exit speeds and high heat build up. Nitrogen can be used to relieve the heat saturation problem, but the mega speeds in a banked speedway are what racing on the edge is all about. Tire selection at a Speedway must be precise, educated and careful since the high speeds demand your best. If you are not sure about what compound or type tire to run at a particular facility, ask your respective Race Tire Director for an application sheet and for his/her advice.

Road Courses are more forgiving, but can often be frustrating, because many road courses also schedule sports car events as well. You will be able to use a wider range of compounds at a road course due to greater probability of change in track conditions, but you will also have to deal with more effluvium on the track surface. Detritus on the macadam is often in the from of rubber particles left from previous races, usually automotive, that will stick to your warm tires and act as a barrier between your tires and the asphalt. Track cleaners can get the majority of leftover crud, but sometimes you will have to bounce back and forth, trying to find the right bite and an unsullied adhesion surface. Rain at a road course can be run with rain tires or a slightly different compound since extremely low durometer tires like “rain,” actually need the cool rain water to keep the tire carcass from overheating.

Tire selection at the site can be greatly aided by walking the track. Composition of the track’s surface (some southeastern tracks had seashells mixed in with the asphalt), irregular lines, previous oil spills, trash can all be duly noted beforehand. This is the one thing that any racer or crew member can do for their effort that can measurably improve their performance without any cost whatsoever. Correct fact lines and highlights can be noted in a small notebook or planner, then read over at your pre-race strategy later.

If you buy, mount and balance your tires, that is fine, but always, ALWAYS make sure that you are mounting the correct size for your wheel. Oddly, tire problems and failures because of incorrect size are fairly common. Don’t gamble by trying to get an extra wide tire in your chassis that will only interfere with your chain, brakes or suspension. Suspension should always be set up first with the proper spring pre-load and shock setting, then concern yourself with what tire to run. Ping-ponging back and forth will only screw up your day, and aggravate everyone because of your lack of insight. Privateer rule #1 reads -- “Proper Previous Planning Prevents Piss Poor Performance.”

Contrary to semi-popular belief you can not warm up a race tire by blistering a cold tire, weaving, or doing burn-outs. This will do nothing to warm up your race rubber but will destroy any credibility you have as a racer and/or tuner. Breaking in a new tire should be considered a slow, artistic process. Like an artist at his/her canvas you are meticulously opening the traction surface of your new tire, left to right, right to left. Be even, be thorough, but most of all enjoy the experience; you are becoming a racer, a skilled individual developing your expertise in competition preparedness. Put your gunfighter face on and use your machine as a paintbrush, creating an overall fine grain sandpaper-like finish, from traction edge to traction edge. Don’t bury the front wheel in a turn on a new tire attempting to heat it up; you’re only raping a new front tire. Warming a tire is a patient, deliberate process. You want the tire to develop its warmth and grip gradually, heating uniformly until the level of traction is spine-straightening upon acceleration out of a corner. On race day, of course, you will be limited as to how much time you can devote to simply warming your tires. Approximately 124 degrees Fahrenheit is the desired temperature where the tires start to work.

Much controversy has centered around the use of solvents, miracle tire preparations and conversely what happens when a tire encounters an oil or antifreeze spill. Most solvents are petroleum based and naturally so is motor oil. Tires even though they themselves are a petroleum derivative in manufacturing, do not survive very will when they experience solvents or oil. Without getting into lofty chemical analysis equations, let’s just say that petroleum in any form physically on a tire messes up their molecular construction. The end result is deterioration and ultimately tire failure. A good friend of mine (who will remain nameless because he worked for a major pro team) once informed me that he was going to use lacquer thinner to prep his rider’s tires for his upcoming race because the rider didn’t have time to scuff them in. He later sheepishly asked if I could find a well to drop them down because they were ruined after applying lacquer thinner (a solvent) to them. Such damage may not be noticeable to the naked eye but rest assured that heat and competition will unlock any compromised tire in short order. For the safety of every competing rider, avoid using solvents in relation to traction. Tires that have met with an oil spill, whether yours or someone else’s, should likewise not be used. A dry, clean tire is best for most occasions.

Adhesion can be moderated by air pressure since a tire seems to be a pneumatic device. One of the most mysterious failures at a race track is a leak-down; “Where is my tire leaking from?” No obvious defects, no nails or woodscrews, gashes or slits can demystify the puzzle. Try looking at the sidewall, right next to the bead of the tire, up near the wheel’s rim. Tires, especially race tires can sometimes be defective in this area from the factory. Your race tire representative will usually opt to replace the tire for you since there is no cure for this particular malady. You can check for this imperfection by brushing soapy water around the sidewall while looking for bubbles.

Defects in road race tires aren’t all that much of an everyday occurrence, but they do exist in limited numbers; the high priority however, is to find them before they have any opportunity to hurt someone. Tires are quite the imperfect science, so there will be odd fluke, but the quality of the majority of race rubber is exceptionally high. Maintaining your tires, like any other part of your motorcycle, can go a long way to stabilizing your racing costs. Before going to the line visually examine 360 degrees the entire wheel/tire combination for flaws. Are both wheels free from any snags with brake lines, caliper hangers, oil cooler lines? Do the fenders rub anywhere? “How long have the brake rotors been cracked like that?” By treating your equipment like the thoroughbred racing machinery that it is, you will extend the life of every part of that motorcycle, and that will in turn, decrease your expenses. To paraphrase someone else, who was similarly idealistic, “I have a dream!” My dream has fit, healthy, well-scrubbed racers who don pristine leathers and ride racing motorcycles like the Silver Surfer would ride. In this perfect world everyone, riders and tuners alike, would have ultimate knowledge. They would treat everyone’s motorcycle better than if it were their own. Dirty wheels would be washed clean with contact cleaner and Tide™ before mounting the race tires. And the TIRES!!, The Tires would be Perfection Itself, free from any blemish whatsoever. They would balance without any weight at all, and they would be marked with that little strip of red duct tape next to the valve stem, that only a faultless wheel can wear. They would be properly scuffed in with just two laps on them and they would be warmed to 124 degrees Fahrenheit for just the right grip. When spun on their axis they would represent the epitome of race tire excellence, inflated to matchless adhesion. All in a single dream! Oh, but what the hell, go out and race on ’em anyway

Vaya Con Dios! See you next month.


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