07 Cup car.
Drove the car the first time last friday with the slicks that came with the car.



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Has anyone seen a damage like this?
Its on 80% of the inner rubber around the tire.
Edit: michelin Cup spec slick!

Also, the car had no grip at all at the back(but that came from the very bad setup the car came with...i know, my bad i did not get a propper setup before driving it...also note the sway bar setting...)
But i was shocked when i saw that. could have ended in a blown tire and a crash...

hope you guys can help!

thanks

 

Was it present before you tracked the car?

Did you look?

 

Seen that once only.

We suspected too much pressure while mounting it on the wheel to get it in place. Never been confirmed. These Michelin are really though to mount. Easier if they leave them under the sun to warm them up a bit before mounting.

 

This can be caused by rolling the car around with very low pressure. Have seen this happen quite a bit with cars that have sat a while with a leaky tire in storage.

We have also seen this when a car with a lot of negative camber is started at a very low cold pressure.

 

I've seen this on the rear tires, only at Daytona, too much camber and probably to little air to start. I doubt too much pressure mounting. They need a lot of pressure to seat. I have not see the failures since Daytona, but always try to start at min 18 psi, and stay off curbs the first lap.

 

Cory and Jerry nailed it above. I would add that 18 psi cold is too low for someone who just bought the car and is probably just taking it easy. I would start 23f/22r or even more and bleed after 4-5 laps. Totally agree to stay off the bumps for a few laps.....

 

hi guys.

thank you very much for your posts. they helped a lot.

i just talked to the guy who delivered the cars to me.
that left rear tire, only had 0.4 bar( so around 6 psi) in it when it left the trailer.
so it was sitting for at least 24hs with 0.4 bar in it.
after unloading, the car was driven 40-50yards into our garage...

guess i found, what killed the tire

but without the help, i would have never asked the guy about the tirepressure..
well
on my first drive, i started with 24-25psi. and then adjusted it to 29-32 psi after a few laps.

but then again, i was only able to drive it 35-40 minutes. so not that much of a "getting used" to ,and adjusting the tirepressure correctly.

 

Regardless don't forget to check the setup including camber, toe, canister pressures, etc....

 

Hi Gorden.

Yes, definitely! This has to be done because the car drove like...well.. dont want to get too detailed here
Oversteer all the way. No grip at the rear (despite left or right hand corners..) and so on

the car has to be checked completely.
usually i do this prior to the first drive.. but well.. no time

thanks for the help!

 

Also, how it handles on crappy slicks is irrelevant. All those manifestations you mention above may well just disappear with fresh rubber. Regardless, you need to check the setup before you go out again and get some decent rubber....