GoKartman

1st track day on a set of Pirelli DH slicks at Lagune Seca with my 01ZO6. They were a set from World Challege series with two 30 minute practice sessions of use.
Dialed in the starting pressures to get 30psi HOT(per mfg's spec) . They had a ton of grip ( better than Hoosier A3's and I was very happy for the price paid.

Last couple sessions of the day, I felt vibration in rear on hard downhill braking (into T2 & T11) that was like anti-lock was activating, except that nothing felt in brake peddle.

Once home, I removed tires and found this:


right rear



left rear


This rubber build up continues pretty much all the way around each tire.
I have seen pickup rubber this large on Hoosiers, but random and from track marbles.

This must be from these tires because there is so much and it is only in bands around the tires.

I'm running -1.3 deg camber & 1/16in. overall toe-in in rear. Shocks are 2yr old Phadt coil overs with T1 bars

Has any one seen this or have any theory as to what is going on here??

GT Racing Tires

That is just pick up and will burn off. You can also scrape it off with a torch and paint scraper.

froggy47

Sidney004

Joe, its normal, it got picked up on the cool down lap coming into the pits; sticky tires do that. It woundn't of been be on the tires while you were hot lapping on line and its not from the Pirellis. If you do a burnout or some aggresive figure 8's in a parking lot, you'll see how easily it comes off(it couldn't of stuck to the tires during a normal fast lap,) You probably still need to investigate the source of the brake vibration. The band where the pick up is adhered to is probably the hottest part of the tire.

GoKartman

I would agree with you guys except ..... there is none of this on the front tires.

I've seen pickup of rubber from hot tires, but always on all 4 tires and randomly located on the width of the tire. As the pictures shows, this is in narrow bands all the way around the rear tires only. This is not all just pickup on the cool-down lap, because there is so much on the tires.

I agree with you, Sidney, regarding the hottest part of the tire. Laguna punishes the right side tires being a CCW track. What bothers me is what is causing the heating on the outside of the right tire and heating in the middle of the left?? Is it a combination of the track & the setup of the car. Keep in mind this setup is unchanged from the Hoosiers, except that these rear tires are about an inch larger in diameter. This in effect raises the rear about 1/2 inch. I'll go back and check ride height.

Sidney004

The front tires weren't as hot as the rears.

froggy47

I think you are over analyzing it. It's in different places on the (hot rear) tires because that's where it was laying on the track when you ran over it.

sebdavid

I agree with the others.