Quote:
Originally Posted by rice_classic
Don't listen to Mr.AC - he's WAY out of bounds on this one - and he's being a ****. Don't listen to ****s.
I raced competitively on used R-comps from 2004-2011 and in 2011 I ran half the season used tires before buying a new set and won the championship that year. I won 4 championship after that racing on tires well past their "fast" points and would get more out of a tire that most people said you could. I often changed them once the cords were showing.
You CAN know the performance of used R-Comp by 2 things. 1) The age and 2) the number of heat cycles. Most racers (who buy new tires) record the number of heat cycles and the reason they do this because most R-Comps have a performance maximum in the first number of cycles; on some it's 3 cycles on others it might be 12+. But even after the performance drop off occurs they are STILL R-COMPS even if they are .5-1.0 second off their fastest pace. As long as there's tread they'll function - but how the function over the duration of their usable life is actually easy info to find by searching proper racing forums (this is not a racing forum).
There's a BMW E30 class here that uses Toyo RRs (in my size) and the fast guys would do 4-6 cycles on them then replace them (even though they would be fast for 12+) so I would get VERY cheap tires. The really fast Spec Miata guys might do 3-5 so I could get Hooseir SM6s for cheap some times as well and they would still be within .3-.5 seconds of their fastest until the darn cords showed.
As for your other questions: If these are for sale - they are "cycled out" meaning they are not at their fastest - but they're still fast. They will probably like camber somewhere from 2.5-4 degrees depending on setup (buy a tire pyrometer) and as much caster as you can throw at them. If you're highly camber challenged then run them with more tire pressure to reduce sidewall flex.
I would expect they would like to be somewhere around 34-40psi hot - but once again - record your data and you'll figure it out. They will not be as forgiving as a street tire. If you graph the slip angle, it falls off fast once you exceed maximum adhesion.
Have fun out there!
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Excellent post!
I use R7s for time trials and use oder Hoosier set for practice and throw on a fresh set for the 'bang' out lap. THis was cost effective as I would win new tires (Hoosier contingency with NASA) if there were 7 participants. I'd use the 'fast tires' for 10HC before retiring them to practice (next year's strategy as TT5 is very competitive).
The older set can get up to 30 HC and they were still a touch faster than my sticker Toyo RR (which as correctly observed, are fast for 5 laps then consistent to the cord dropping half sec or so per lap).
Best bet is to get 225/45/17 Contis from Bimmerworld. You'll get a good idea on what its all about. The R7s are marginally faster than the Contis I ran but FWIW, perfect for track days.
Lutfy