mark kibort

I just had a race at Laguna last weekend and these A7s with at least 3 more sessions of track time left on them, were slick as ice. my old used A6s i used to get from a buddy campaigning a 500hp mustang used to last me at least 8 sessions after he donated them to my racing efforts! These are hitting 8 session and are garbage. i had them at ACS last month and people were noticing how loose the car was . my other set that i bought new, cleaned that up, but they were not great and were horrible at Laguna. both around 8 sessions total now.
I've heard the A6s didnt last as long as the A7s, but maybe the A7s last longer but heat cycle out faster. any one have experience to share?

josserman

That's surprising, I've heard the same as you. Maybe it's a one off, as I'm sure you know there are too many variables that could effect this, one set doesn't provide enough data. Subscribed for other comments.

mark kibort

I'm thinking the higher heat and wear of the super speedway banking might have accelerated not only the wear, but maybe the reduction of heat cycles available for decent grip.

Plavan

I would only use A6's when it was cool outside. Never when it was over 85 degrees. When they got too hot they are like ice and do not last long on my light car.

mark kibort

i havent seen that issue at all. i heard the same thing until my close friend in his 500hp mustang and ALL the corvettes started to use them regardless of temp. when they ran 1:29.xx at laguna, people noticed how they work in hot temps, even toward the end of the race on hot days. one of the main things they were doing, was using lower pressures to start than most would use.. similar to real slick starting pressures. 22-24, ending up at 30psi. tire temps across the tire seemed to confirm this was a good setting. certainly, any tire will start to go away when over temperatured
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fatbillybob

Mark,

Isn't it a moot point? You have no choice since no more A6's. Besides Porsche guys follow all the rules. Hoosier says R7 for you and hot around 40PSI.

jonb94112

I have found the A7's to be magic for the first HC or 2, but also found that they are really sensitive to how they are treated and if not run easy and allowed to cool per Hoosiers recs, they will not last. That would be my guess for what you have found as I have had mixed results depending on well I treated them from the start. Hoosier also told me that if the R7 gets in the right heat range, it can be as fast as the A7. Great tire, but I don't know about that one. Same with their 'recommended' pressures.

wanna911

I agree, the care of them is vital. I've had probably 30 sets of A6/7 since 2011. I've never had a set that wasn't usable to the cords that I got as stickers. However I bought some used ones to see if bigger sizes worked on my car, and even though the tire sizes fit, the tires were all over the place. Thought something was wrong with my car. I ran a 26.9 at Road Atlanta on a cord session of 22 hc A6's. I can't get the A7's to last anywhere near that long, they seem to cord at 16-17 hc on my car which is TT only and an occasional long DE session. If you overheat them, they can be trash afterwards. I never have because I don't race and long sessions are done in the mornings.

mark kibort

im wondering then, if ive overheated them at autoclub speedway.. they still look pretty good, especially the rears, and in the A6s they would have been half gone. now, at 10-11 heat cycles the are toast. lowered the pressures from 34psi hot to 30psi hot and they were slightly better, but still garbage. the 7 year old used A6s were much better . maybe its the overheating, maybe they just dont like to go over 9 heat cycles, or maybe i should just change to the Hoosier R100. (i thought it was the same compound as the old A6) what is the difference between the A6 and A7 for recommended pressures. the A6s were in the 34 range recommended. we just found that the larger cars were having faster laps and better temps across the tire at 30 psi hot. dont know if the A7 responds to this as well . i do know before i lowered the pressures in the R7, the centers were hotter than the outside and inside areas. pointing to over inflation.