EzsCBR:Right know I am running Dunlops at 32 f 32 r I know that track guy run there tires on the soft side to help out with grip so I was wondering if that tanslates to the street. The tires feel fine but I haven't pushed them hard but I will be in a couple weeks. If you have more insight that would be great.
nothing about track tire pressure really translates to the street. at the track, u run a certain pressure to maintain a certain tire temperature. lower pressures cause the tire to run hotter because the rubber deforms more. as it deforms, all the rubber molecules rub up against eachother, creating friction and therefore heat. because of this, running on the "soft side" for more grip is not always correct. there is a point in which ull get less grip w/ too little pressure at the track, meaning the tire is too hot and melting off.
while tire temp and starting pressure is very dependent on the actual tire, a good place to start out is measuring the pressure increase from cold to hot. if the tire psi increases 5psi after a hot session on the track, u started w/ the correct pressure and are running at the right temp. if the tire psi increases only 3psi, remove some air. if the tire psi increases 8psi, add air to the tire. counter intuitive yes, but if u consider how the tire makes heat, it makes sense. another thing to consider also is that rider ability/speed has a lot to do w/ how u work the tire. a slow C-pace rider wont ever get enough heat into a DOT race tire, so they can run less cold pressure. but the second that rider starts getting faster, theyll need to watch tire pressure/temps much more closely to maintain good grip levels. i actually started out my last trackday w/ a 5psi increase in pressure, so i left the tire alone. however, by the end of the day i had dropped 4-5seconds off my laptimes and started cooking the tire. i should have noticed sooner, woulda saved me from having to buy a new rear tire.
however, as u can probably already guess, u r never that concerned w/ tire temp on the street. u give the tires a few blocks to warm up and then stop worrying. given the wide range of conditions on the street including the range of riding that ull be doing (freeway, around town, at night, etc), there is no possible way to maintain optimum operating temp for the rubber on the street in all conditions. because of this, tire pressure on the street is really only concerned w/ feel. more pressure usually makes a bike turn in quicker and feel more nimble, where as less pressure may offer a slight increase in overall grip. so, your street tire pressures should balance these two concepts... pretty much run them where u like the feeling in the bike. and honestly, if u 'feel' a difference in the bike/grip with a 2-4psi change, either the placebo affect is taking control of your head or you are riding too fast for the street.
the final thing to consider w/ street tire pressure is mileage. technically, a tire should wear less at higher cold pressures. itll run cooler throughout your commute and therefore less rubber will be used each mile. however, ive never seen any hard data or proof to support this. while im sure there is an ideal pressure for maximum mileage, id bet we r only talking about a difference of around 5% or so... maybe 2-300miles. the flatspot commuters develop would prob be thinner w/ high pressures and wider at lower pressures, but who knows which one will last longer....
ok ok, end essay
hope all that info isnt an overload and actually helpful.
Naked 93' F2...... RIP -- 04/12/07
04' 600RR Black - currently stuck between track and street usage
- Brembo Master, Sato's, & Ohlins out back