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i'll be going to VIR w/ pretty new 615s.. by the time i go id only have 2 weeks of daily driving on them.. maybe a road trip to visit the folks (100miles) for a first heat cycle..

615s dont really have normal smallish tread blocks though.. id guess theyd be less likely to chunk than like an all season tire.. eh?

Thanks for the PM Vincent. For the moment the plan is to get some FK451 as street tires real soon. The F1 SC will just be for track and the ride there and back. If need be I'll run the FK451 on the track. I won't drive to RA or RR on shot tires. Right now I have about 4/32 left on the SC so they should get me through RA and VIR-N. I went to RR and back and the wear was pretty minimal on the SC. Since I'm old and slow my tires don't wear much like Rob's do...

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http://www.greywinds.com

again, drove VIR Full on 451's with maybe 15 miles on them. my car does have sport suspension with added castor & camber but no chunking and excellent wear.

Mark told me about a way to heat cycle tires. drive enthusiastically on & off a few ramps on I40, then come home and put the car on jack stands for 48 hours. i did not have an oppurtunity to do that before VIR so can't attest to its results.

i knew when i went to rockingham i should have brought extra tires as mine were borderline. one spin later i coasted the balance of the weekend on greasy michelins. it kinda sucked.

Steve has an enclosed trailer so he has no excuse for leaving his backup plan at home!

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Vincent Keene
'06 Ford Mustang GT (track rat)
'15 Dodge Charger R/T (yeah, it's got a HEMI!)
'07 Ford Fusion SE (205,000 miles and counting)
'98 Chevy Z-24 (retired)
'93 Acura Integra (Team SWB 24HOL Car)

I've ran new Azenis 215's on track a few times. At VIR, chunking should not be an issue. Done it twice and so far, never an issue. Surprisingly enough, I did't experience chunking at Rockingham either, but they still wore out fast there.

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“I feel safer on a racetrack than I do on Houston's freeways.” - A.J. Foyt

Kevin Butler
Mobetta Autosport Spec E30 #612
2003 C5 Z06 Corvette
AFR Miata, SM2 61, '93 w/200 SC'd RWHP - soon to be resurrected
Waaaay too many other projects....

just finished assembling my tire rack, now to mount it in the trailer. one less excuse for being slow is gone.

Here are some late thoughts to the thread.

I see no benefit or reason to "heat cycle" street tires.

Ful tread tires in excess of 4/32 will start to chunk when worked hard on a heavy car. Might get away with them on a Miata or a Honda but anything heavier and I believe you are asking for trouble.

Before I had too many wheels to count I went to the junk yard and bought a set of extra rims for the USS Audi. The car....and driver were not capable of going very fast so that wasn't an issue. I just didn't want to wear out my good street tires on track. I would go to Sturdivants and buy used up tires to run on the track. All of $10 each mounted.

My REAL quote on tires for students is to ALWAYs run worn out streets. Until of course you want to compete in the time Trials. But by then you have enough experience to benefit from stickies. If you don't plan to compete in the TT stay on streets. Others will pass you but I guarantee staying on streets will make you a better driver.

Ron

Matt Nicholson and his time on the outside of turn 2 at Roebling may have a slightly different opinion.

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Rich
http://www.v8mongrel.com/

My understanding is it had nothing to do with heat cycling but rather really cold tires. I'm not saying run tires with NO street miles. Sure run them for 20 miles but thats not the same as heat cycling.

Ron

My recollection is that he was on lap two or three and they turned to grease. I could be wrong, but my point is that you should never run virgin tires on track. Shaved or not, all tires go through a chemical process the first time they are used, and while a street tire does not require the same type of heat cycling as a race tire it still needs use before being driven in anger.

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Rich
http://www.v8mongrel.com/

I agree and as I said, run them for 20 miles or such. What I understand you are doing is burning off the mold release compound they put on the molds so the tire carcass is easily removed. The chemical change I think you are refering to is the reallignment of the rubber molecules to strengthen the compound. This really has little affect on street tires.

So yes, to be clear, run even streets a while but thats not heat cycling.

Ron

I remember asking Matt about this at the time of the incident - this was most likely a mold release issue. He was on brand new Azenis with 0 miles, and had trailered the Sentra to Roebling. After the spin, I think he put a few street miles on the tires and was golden for the rest of the weekend, tire wall scuffs notwithstanding.

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Tom Freeman
'98 M3/4/5 | '93 Spec3 325i | '12 TSX sport wagon | '03 Tahoe
Team Silver Bullets '91 240SX

I disagree. That is indeed a heat cycle. Is it the same amount of heat and duration needed on a race tire? No, but even race tires vary in those specifics. And I think that there has to be a certain amount of heat activated chemical or molecular change in a street tire, otherwise shaving a street tire would remove the mold release and thus the need to run the tires before use.

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Rich
http://www.v8mongrel.com/

Shaving a street tire DOES remove the mold release compound. Or more specifically the rubber which has it on/ in it.

So what exactly do you accomplish by heat cycling a street tire?

You don't heat cycle a race tire to get rid of the mold release stuff. That's a side benefit. You heat cycle the tire to activate the chemical reaction we've already talked about. Its this change that leads to the longer life of the tire.

Street tires already have a long life so heat cycling them does nothing. ....except burn off the mold release stuff. That's why I'm not calling it a heat cycle.

I have the feeling we are now officially running around in circles:)

R

I guess we disagree on the idea that, disregarding the mold release issue, there is no chemical or molecular change in a street tire when heat is first put into them. I think there is. I don't think that the compounds of street tires are so far removed from those of race tires that the same chemical processes would not apply. A top line street tire must share a lot of its technology with a race tire in order to maximize grip. I agree that there will be concessions to wear that would not be made in a race tire, but I think that those would not be so great as to make heat cycling not work in the same way.

Does an A032R or RA-1 require heat cycling? If not, then obviously I am wrong. However, if they do, I cannot see why a tire like an Azeni, which in reality would not provide significantly greater street mileage life, would not also benefit from heat cycling.

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Rich
http://www.v8mongrel.com/