Overdriving the Tires? Corrective techniques?

#1

In the CMP race report, Steve F, mentioned that he was overdriving the tires. This is definitely what happened with me on Sunday. My car got so slippery I felt like I was on a wet track with slicks. Only problem is I’m not exactly sure what are the driving characteristics which cause this heat build-up. Obviously, the guys up front are going quicker through the corners without heating up the tires the same extent.

I did some quick searching, but couldn’t come up with a good explanation of techniques which cause this. Can anyone offer words of wisdom or direct me to a good source of explanation?

Thanks.

Keith

#2

Keith, I hope someone can explain this also. I really don’t think I can drive any better than I did in the first five laps of both days. I started out at 32 lbs Saturday and finished the race at 39 on the right side 40 on the left side. The discription of driving on ice is exactly what it felt like. Sunday I started at 31 lbs and finished with exactly the same pressure as Saturday 39 and 40. This was the fourth race weekend on the same tires, with practice, qualifying and races. If you figure three heat cycles each day multiplied by 6 days, the Saturday race was the 19-21st heat cycle and the Sunday qualifying was 22nd and 23rd for the race. I would estimate there is still 1/32 of thread left on my tires with visible grooves. Are these things junk after 23 heat cycles or do you and I just suck?

#3

It’s really subtle. Basically, if you feel like you’re going fast, you’re heating up the tires. You can’t slide the car any, you have to be super smooth, don’t find the limit by touching it, but by seeing it coming. Really hard to describe, but you just can’t expect to push 100% the whole race and not have the tires go off.

If anyone is interested, I guess I could put together the whole Sunday race video for you to see, but it’s pretty boring because every lap is the same and I don’t know what you’ll be able to tell from it.

#4

As I understand it, fresh tires will be more tolerant of heat and yield more grip for a longer time than those with a number of heat cycles on them. And logic would suggest that how close to perfection you can be will extend how long you can run hard before the tires start to go away.

That said, in the DE session after Sunday’s race I found that parts of the track had gotten quite slippery. In particular 11 and 14 were pretty slick and going in slightly slower and deeper worked lots better.

#5

I think I was having this same issue on Sunday. Plus I think when I was driving off line I picked up a lot off rubber. I’ve never experienced anything like it. The car just wouldn’t go where I wanted it to. I thought I had busted something. But after inspecting the car there’s nothing busted or wrong.

I hope the old beat tires I was running was part of the problem. I’ll have fresher rubber for VIR… so we’ll see

#6

I ran a 2.00 on old as hell tires saturday morning.

I ran a fast lap of 2.02 Sunday afternoon on tires with 2 heat cycles on them.

There is a combination at work here where if you were on old tires Sunday afternoon, you were pretty much doomed. You can get away with running the old stuff early when the track is still relatively cool, in the afternoon you had better run the newest stuff you have, whether it is shaved or full tread…ask Travis about that.

The track actually would have been better if it rained a little Sunday afternoon.

Al

#7

FARTBREF wrote:

[quote], in the afternoon you had better run the newest stuff you have, whether it is shaved or full tread…ask Travis about that.

Al[/quote]

Al, are you saying new unshaved would have been a better choose then old shaved on the afternoon session?

#8

Jeff, Al doesn’t have to say it, I’ll say it…yes is the answer to your question. Travis passed me like I was sitting still. He would get a run comming out of the carosel that would last until turn 10.

Who would have thunk it? I guess Travis did, and now he has a good set of rain tires that were cheesegrated to 6/32" at CMP. Moral of the story:Cheesegrater tracks like lots of rubber.

I hate that track.

Regards, Robert Patton

#9

My thinking is since the tires have more tread it is taking heat longer to build up in them and thus longer to get greasy, etc. Apparently this is offsetting the squishiness of the full tread depth. I noticed the 7x7 car had full tread too.

Thoughts? Maybe that is stating the obvious?

#10

I am ready for 150 treadwear tires…

Seriously, Toyo is phasing out the RA1, having fresh tires is getting critical in our series and it is getting expensive. I think the real life of the RA1 is 12-15 cycles…Toyo makes a performance tire that is used in the STS autocross classes, maybe we need to talk to Toyo and see if it is suitable for race applications. i am willing to bet the RA1 replacement is stickier and thus will have a shorter life. I am serious about this I think it would make the series even more "fun" a more consistent, longer lasting, cheaper tire. It would have to be a Toyo though, as their support has been great.

Al

#11

Going to a harder tire isn’t always the answer. On an abrasive track a hard compound may not bite into the aggregate of the track surface and produce grip. This grinds the rubber off the tire like a dust rather than getting the tire fully hot allowing it to sheer and make marbles. A softer compound can bite into the pavement better giving more area of rubber contact with the road and provide better adhesive grip. Even on some occasions you get better wear because the car doesn’t slide around so much shearing those bonds of rubber. Obviously the track temp and ambient temp have something to do with this too.

#12

At the National Championship last year, the Toyo engineer told me to run the tires down to the cords, and then throw them away.

And I turned my quickest times of that weekend on older tires, just before they corded.

Carter

#13

Carter, I’ve run CMP three times, there was just something very different about the track this time verses previous visits. Hot, abrasive asphalt seems to make these tires need more grip. Travis was very fast on brand new unshaved tires.

#14

Interesting…

And weather, time of year, etc. can make a difference. However, I’ll put up a steak dinner to anyone who can turn a faster lap than I, with me on older worn tires and the other driver on unshaved new tires.

Damion is a fine driver in a good car for sure but with unshaved tires, and me on half-worn tires at Road Atlanta, he didn’t have a chance.

Scott Lear was on full-tread tires at Summit and was struggling. I know he could have turned quicker times with worn tires.

I have mine shaved to 6/32" and after a session or two, they are good to the cords.

Carter

#15

This is interesting…back in Feb, Travis turned his fast lap (next to lap record) on old tires…I have run fast at CMP on old tires in cool weather. My pole on saturday was on absolutly fresh shaved tires…CMP really seems to go away in the afternoon. I have talked to many folks who said Toyo’s are the absolute best when fresh/shaved…IO think a lot depends on track surface and temp. I think that you can get away with heat cycled to death tires when it is cool out. CMP and the rock require fresh tires when it is hot. Also I would rather run both of those tracks in the rain rather than 90+degree afternoons…

Al

#16

Al experienced the same thing I did. My tires had four events on them and I would estimate I had 2/32 tread left. The car was incredible for the first 7 laps and almost undriveable after max tire pressure was achieved. I gotta think the number of heat cycles and the hot abrasive track conditions are the only difference.

I did not have this problem at CMP when I ran with the Mid-Atlantic guys earlier this year. The only difference is my tires were fresh shaved and only had two heat cycles in them. The track was cooler then too.

#17

Gasman wrote:

[quote]Al experienced the same thing I did. My tires had four events on them and I would estimate I had 2/32 tread left. The car was incredible for the first 7 laps and almost undriveable after max tire pressure was achieved. I gotta think the number of heat cycles and the hot abrasive track conditions are the only difference.
[/quote]

well I don’t have much data to be of much help yet, I only have 13 heat cycles on the most used tire I have but out of curiousity what tire pressures were you running? And where do you measure your hot pressures?

#18

Simon, Saturday started out in the morning at 32 all four, and measured 39 right and 40 left as soon as I could get a guage in my hand after exiting the car. Sunday because of the problems Saturday, started lower and ended up with the exact same pressures. These tires had approximately 21 heat cycles on them.

#19

Steve, I think what you felt at CMP was just a bad track that got really greasy in the afternoon heat. Our race was at the hottest part of the day. Everyone was sliding around.

#20

Gasman wrote:

Take this for what it is worth (not much ;)) as I have limited experience with these tires, but I think those pressures are a little too high as well. From my experience the pressures can drop 3 psi from a hot pit check to checking in the paddock or where you are parked maybe more if you did a long cool down lap. My car has been the best in the 38-40 range hot right off the track meaning right in the pits after completeting a hot lap (no cool down lap). Right now I’m starting them around 28-30 cold depending on track, corner of car etc. The symptoms you described are the same as overinflated tires. I would still not rule out that the tire has been heat cycled out and that a fresh set for those conditions would have been better but you might try going even lower on your tire pressures or have someone check them in the pits for you especially on a hotter day.