KCblues

I'm new to autocross this year, running a 2004 Z06 in AS.

I'm having a new set of Bridgestone RE71R mounted next week and neglected to have TR heat cycle them for me before shipping.

There's a test and tune at Lincoln next weekend that I'm signed up for.

How many runs and/or what temperature should I get these tires to for the first heat cycle? I do have access to a tire pyrometer..

I understand they should be left alone for 24 hours after the first heat cycle.

63Corvette

Bring them up to operating temperature gently. Do not heat shock them. After one session of slowly coming up to speed (not over it, and no sliding or locking of brakes) let them sit for 24 hours if possible, or at least overnight.

skxf430

Are you towing your car to the track? Or, is this a street car and you drive to the event. If your car is street driven, you have already heat cycled the tires from the time you drove it from the tire shop to your house.

KCblues

It'll be driven home on an August afternoon in Kansas.

Is there some target temperature I should be shooting for?

63Corvette

On the Track
Heat cycling can be done by installing tires on the car and running 10 to 15 minutes on a racetrack. Start with easy laps, and build up speed as the session continues. End up running 5-10 seconds off your normal pace and be careful not to spike the tire temperatures by spinning, sliding or locking the tires.

An important step in tire heat cycling is that after being brought up to temperature, the tires require a minimum of 24 hours to relax and relink the bonds between the rubber molecules. Drivers attempting to heat cycle tires in the morning for use a few hours later in the afternoon will not experience any benefits from the morning attempt at heat cycling. Heat cycling tires on Saturday means not using them again until the same time on Sunday.

Supercharged111

Overrated, I just run them at least once in practice but don't always observe the 24 hour rule. I'm not alone. Hell last year I had a virgin set of full tread RA1s and when it began to rain I just threw them on and raced. Not sure what the big deal is, I know part of it is to work out the juices from the molds but my lap times don't seem to imply that cycling really matters.

Bill Dearborn

Since these are street tires and not race rubber driving them on the street may get them up to temperature since street tires are designed to operate at a much lower temperature than race tires. When I was trying to heat cycle some R compound tires on the back roads and highways near my house I never got them over 135 degrees since I couldn't drive at high enough speeds or corner as fast as required due to safety concerns. R compounds aren't considered hot until they reach temps in the 190 to 200 deg range.

Bill

KCblues

I talked to Bridgestone telephone tech support yesterday. Asked about recommended operating temperatures and heat cycling. They didn't know anything but promised to ask the motorsports person call me.

Xian

There's not a ton of data out there on it but I'd suggest cycling them if you're able. Accepted temp range is a minimum of ~150-160* while trying not to slide/tear them. Anecdotal evidence seems to indicate you'll get better wear but not necessarily better grip out of HC tires.

This being said, there are a BUNCH of folks who've run them without any cycling. A pretty decent population of those folks have had graining issues initially and funky wear. I don't know/haven't seen anyone run into the same issues with heat cycled tires.

KCblues

Thanks Xian,
It was one of your posts that got me chasing this down!

Xian

Ahhhh! Lol

FWIW, I had my most recent set cycled by Phil's Tire before the shipped them out. I figured that for $10/tire it was a cheap investment given the typical hassle of finding a place/time to cycle them on the street.

93Rubie

I agree with this. I've got some great wear out of a few sets at this point of 200TW street tires even with a camber challenged car.

I usually just drive the car on the street for 30-40 miles and take some back roads on the way home to warm them up but not too much. Then let it sit for a day or so before I run them hard.

Wear also depends on surface type and tire pressures. Concrete or rough asphalt tears at tires MUCH more than smoother asphalt, you also have less grip, go figure.

KCblues

Thanks to all for the advice.

Found a nice big asphalt lot at an abandoned mall and drove some reasonably gentle figure 8's until I got to approximately 150+ degrees. Finally got to put the pyrometer to some use. Interesting that when I got them to temperature the inside edges on the front were about 20 deg higher than the outside (170 vs 150). I'll have to see if that continues on the concrete at the TNT tomorrow.

Xian

I'm doing a TnT at Dixie tomorrow... wish I was close enough to do a TnT at Lincoln! Curious, is there any difference in balance for you at Lincoln vs. other sites? It'll be my first trip out there next month and I'm not sure how the car will respond to the surface.

KCblues

Bear in mind I'm a novice at this game... but I've found this car to be amazingly well balanced and predictable on both asphalt and high-grip concrete. And I have seen a good range of surfaces this year: 3 big asphalt lots, the concrete at Lincoln and Salina, and our home site which is a mixture of concrete pads connected with asphalt strips. The grip at Lincoln (and Salina) is pretty amazing compared to asphalt. Early this spring I took a 3-day Evo school at Salina and then proceeded to slide all over the place at my next event on the asphalt at Heartland Park.

Lincoln is 3-1/2 hours from home, but I'm skipping a local event this weekend because I really need practice on the big site. TnT tomorrow and autox on Sunday. I've been up there 3 times this year and don't think I've been aggressive enough there. I think there is something about the length of the courses and the sheer size of the place that's intimidating me. It couldn't be the driving...

speedwaywhite

I have a new set of Bridgestone RE-11's purchased from Tire Rack. Tire Rack advised me to put 500 street miles on the tires before tracking.

ZedO6

Good advice but not to heat cycle the tires, more to wear the tread blocks enough so the tire will have full contact and you won't overheat the tread blocks, which can lead to chunking and other bad suff.

Tires are manufactured square, that is not to have "camber". Obviously even if your car's alignment was set to "zero" camber, it would not match the "zero" camber on the tire until some of the tread was worn down. Once the new tire is worn to match the "camber" on the car, it will get full tread contact with the road surface.

speedwaywhite

Thanks for the info.

Xian

Sooooooo... how'd the weekend go?

Errrrrrr, not exactly. You aren't going to "wear camber" into the tire in 500 miles. You'll scrub off the mold release and possibly knock off the edges of some of the tread blocks (depending on how hard you run) but you're certainly not wearing the tire to match the camber on your car. In fact, you don't want the tire to "get full contact on the road surface" due to straightline wear. Why? Because the car and tire rollover when you're cornering (which is why you run negative camber in the first place). If it "matches" like you're describing then it'll be compromised during cornering...

As far as chunking tread blocks, that can happen any time the tread blocks are overtaxed by heat/load/abuse (which will then depend on what the tire compound/construction can tolerate). I've had some tires still begin chunking down at 3/3rd's (Sport Comp2's). I've had other tires that are fine at full tread depth (Z1 Star Spec, Z2 Star Spec, Rival, Rival-S, 71R). It depends on the application (DE, racing, autox, TT, aggressive street driving, etc), how hard you're beating on the tire, and what type of tire you're running.

Supercharged111

Has anyone ever chunked a tire or otherwise suffered ill consequences from not cycling a tire and allowing it to sit for 24 hours afterward? Because I haven't.