multi21

Tire Rack offers heat cycling when you buy tires. Once the polymers (sp?) expand and then bond back together after the initial heat cycle, it is said that after 48 hours, the tire is optimal for longer life. I have found that this DOES work as opposed to not having them heat cycled.

I've posted this before, but I had a nasty spin with the MPSC with no warning at all. The tires cost me a lot of money and because there was still tread left, I was going to get my money's worth regardless of the drop in my timed runs. Needless to say, they were heat cycled far too many times and were hard as a rock unless in hot conditions. I ended up throwing them away after the spin.

JimStrott

And am I right that some believe street driving constitutes a heat cycle, while some believe it doesn't reach high enough temperatures to count? How about around-town driving with more turning and braking, vs a highway trip (e.g., to a DE)?

-Jim

multi21

Your 100% right. The tire can't differentiate between a track event and a "spirited" drive through the mountains or canyons. A drive on a hot day on asphalt with several cornering segments would constitue a heat cycle. If it was mostly highway driving that is mostly straight, I can't see the MPSC heating up to their optimal temperature or beyond. You'd definitely have to "Put some heat" into them yourself.

38D

Formula V can bring some stick back to a heavily heat cycled tire. And yes it does work.

LVDell

I give up, what exactly is Formula V?

rodneyr

Well,
I would say it all depends. I seem to be on the extreme curve of the tires in terms of how long they last. I finally replaced my tires after 16 DE's and over 3,600 miles of which around 1,500 were track miles. BTW, I did not get down to the cords..

So, with 16 DE's I would say I had approximately 50 heat cycles. I know even after 13 DE's I still would generate about 1.5 g's on the Left Hander at Lime Rock based on my Traqmate GPS. I am sure the limit of driving is me and not the tire. So, unless you are David Murry or a Pro racer you will probably not get to the limit of the tires. Of course, the tire will eventually lose grip. Most of my DE were around 20 minutes in duration.
So, you really have to qualify how long & intense the sessions are. Individuals could have 30 minute vs. 20 minutes sessions which is significantly more.

street

One of the Michelin reps at Parade is the Cup's engineer. He says they are good for 50 heat cycles no problem. I've got 30 on mine.

38D

It is a liquid traction treatment. You roll it on and let it dry. Brings back stick in older tires.

LVDell

Ahhhh...... very cool. Thanks for the info!

db_gt3

If I may just chime in for a moment, it has been mine and other fast person's experience that the MPSC will start to lose grip significantly after about ten hotlaps. These are buttonwillow laps; 3 miles per with lots of hard braking, fast corners and not a whole lot of straight (configuration #13 with bus stop). They start to feel "oily" after 10 or so laps. Gotta wait for them to come down in temp and then they are fine.

That being said, I wonder what kind of heat cycle I am putting into these things as they never really cool down. The way we run I never really take more than about a ten or fifteen minute break between sessions (except for lunch). I have felt the tires numerous times right after a sesh and again right before the next, they remain very hot after a short break. Only slightly less hot.

When I stay out too long and get that oily feeling underneath me I am sliding through everything. The tires are so hot I can barely touch them. Then I wait ten to fifteen minutes and they are JUST RIGHT (still very hot). Take them back out and they are once again sticky.

Thoughts?



Current Setup:

MPSC
Schatz Alignment
Cup Brake Ducts
Brembo Floating Rotors (front)
RS Flywheel/Clutch
Tequipment Roll Bar
GT3 Cloth Seats
Sabelt Harnesses
Center Console Delete

LVDell

Do you take tire temps immediately after you come in with a pyrometer. If you do, do you also take temps in 3 spots across the tire (inside 1/3 , middle 1/3, and outter 1/3)???

db_gt3

Nah, I just use the ol' index figer pad. I get very even tire wear.



Current Setup:

MPSC
Schatz Alignment
Cup Brake Ducts
Brembo Floating Rotors (front)
RS Flywheel/Clutch
Tequipment Roll Bar
GT3 Cloth Seats
Sabelt Harnesses
Center Console Delete

multi21

Pyrometer is the only way to go.

That is a good question. I don't know if that constitues one heat cycle or two if the tire has gone beyond the optimal operating temperature, backs down to optimal and then back up.

Buttonwillow puts a lot of heat into the tires however. Even running in February at that track, I can't get a full session in without tires getting greasy... regardless of brand, R-compound or street.

Holger B

What pressure are you running when hot?

Mike K.

If they are getting greasy towards the end of a session then they are probably over inflated. Recommended hot 32 f - 34 back can still feel greasy . Try dropping a pound and try again.
I used to really like ( hot) 28f 30 R until I found out it cooks the (R)sidewalls and the tire will blister and go flat. So, try a pound or two and then work with the swaybars.