Quote:
Originally Posted by strat61caster
They heat cycled out, there's only so much heat and deformation rubber can take before it loses it's desirable properties. A lighter lower powered car will put less heat and therefore less wear into the tire compound than a heavier or more powerful car, racing karts the upper classes only got 1-2 days out of a set of tires, the novice groups could run the same tire for a whole year. Not sure what kind of input you're looking for?
Tire science is probably the last black magic art of racing. I remember talking about the hysteresis of rubber and trying to determine it's life but googling wasn't helpful.
It would be helpful for the rest of us if we could understand what you mean by "9 sessions" before noticing a dropoff in grip, we talking 9 track days of 100 minutes on track or 9 20 minute sessions. I know I'm not the only one considering RE71R's for next year but the reports of short life makes me want to stick with a more durable "200TW" tire.
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As far as what kind of input I'm looking for, I would love to hear someone else's thoughts on that plateau in temps at the last big corner, more specifically my theory relating to sliding vs. static friction. I've got some books on the way to hopefully provide some more insight on that behavior.
Regarding the hysteresis of rubber, my understanding is it's all extremely proprietary and compound specific. I think the only way for us to determine the "heat life" of these tires is anecdotal.
Quote:
Originally Posted by CSG Mike
How many laps do you do in a session, and what kind of temps are the tires seeing? Do you have any pyrometer data?
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Sessions range from 8-15 laps, max 25 minutes. When I get into the shop in a few hours, I'll post up some more detailed information about the session duration. I don't have pyrometer data for the last half dozen sessions.
Basically, I'm aware the tires are heat cycled out, but I'm trying to narrow in on the best way to confirm that with the IR data. If that plateau at the end is what I think it is, that's a clear sign that we reached the tractive limit of the tires much earlier than before.