Veloce Raptor

Mark & Joe, it is 100% true, proven again & again.

Chris, I am sorry, but I don't know.

Bryan Watts

Interesting...my experience has been different. I noticed a definite drop off in times after the first 2-3 heat cycles when I ran them in Spec Miata...after the drop off though, they did seem to last at the same grip until they corded. None of the Spec Miata or World Challenge guys ever seem to be running corded tires. They tend to play by the 2-3 heat cycle rule as well.

Veloce Raptor

Well, first, Bryan, would you trust your race to tires about to cord? I wouldn't. Second, maybe they behave differently on ultra-light cars like SM's, but in sedans, they behave just as you describe (inverted bell curve) but significantly improve towards the end, irrespective of 2 heat cycles or 22.

forklift

Prior to my Hoosier addiction I ran RA-1s for about 3 years, probably 9-11 sets . I got a zillion (50+) HCs when I started, but as I got faster that number dropped quickly. That last three sets (all shaved) lost quite a bit (almost a lot) of grip in the rears on HC 27 or 28, all three sets did that with no signs of cording. The rears would give up without warning at mid corner or exit, almost like they had too much air in them….not fun.

A google search found that some of the spec miata guys toss theirs after 12-15 HC, or make them practice tires.

My experience is that they will heat cycle out before they cord.

Veloce Raptor

Heh....mine cord before they HC out.

986

I know a few people who run MPSC backward. (in the dry, of course)

They should not be "flipped on the rim" though, since they use different rubber compound for the outside and the inside.

mark kibort

when i get the WC tires, they have about 2-3 cycles on them. this means basically, i have a new tire! Ive heard that the new tires have maybe .25 seconds in them, and thats the reason for them going new during qualifying. (also, if they are wearing an edge, they dont get a blowout for going beyond cords in the race) However, there are several cars and drivers that leave a race and practice set with an even wear pattern. thats when i grab'em.

After that, i can get amost a full season of 3000miles of commuting as well as all the practice and qualifyiing for a 11 race season. (and thats on a near 3000lb car with 320rwhp)

my last practice session at T-hill found my fastest time on tires ive been using since last season. even faster than my qual and race times. the rears are getting very bald looking, but are still gripping quite well

mk

Greg Smith

Have you finally cooked those kooks yet?

TheOtherEric

This is true for some tires; they can delaminate due to the tire construction. As was noted above, it's not true for the RA1.

Veloce Raptor

Yes.

RA1's will be back on the car next weekend.

Bonster

***I couldnt agree more! I hit my record lap time at Thunderhill last year, only to come home to three out of four tires with cording. Strange how that works.

Bonster

***I like to put a couple of heat cycles on my RA-1s before I will consider racing them, so I use them as practice or test day tires at first. They will then easily go for several race weekends or a bunch of open track days. I know at least one guy who won't race his tires if they have more than 3 heat cycles. He's the regional and national champ, and has the money to throw away, I guess. Not me . .. I can't catch that guy anyway, so I choose the more frugal route, as you described.

Dr.Porsche

What hot temps to shoot for with RA-1s? I'm new to them. Thanks

Bonster

I don't personally use a pyrometer, but the psi you want to shoot for is between 39-41 pounds. Keep a little notebook -- what track, weather that day, etc., and the recordings of cold and hot pressures. Eventually this will become committed to memory, but in the beginning, it's a really good tool to use.

Dr.Porsche

Oopps, all this talk of temps, I meant pressures.