[jmunjr]

I just started running racing slicks in January for the first time since I got my car in 2008. The first time was at Circuit of the Americas in January then again early February. I did a total of three days and 15 sessions. The wear and performance results were pretty good. The outside of the tire wore a little more but tire temps generally were pretty even across the width of the tire are each session. Tire pressures generally were in the high 30psi range. After those three days the tires still have some tread left and will be even more usable if flipped.

FF to this past weekend. I went to Texas World Speedway, a track I know very well. I ran brand new slicks to start the event and the wear results are disappointing. I ran only three sessions on day 1 and only three on day 2. I even flipped the tires after the first day. One of the tires corded after the 6th session and the other don't look so hot.

COTA is a butter smooth track and brand new. TWS is an old track with a lot of rough spots and bumps. I also drive TWS harder because of its familiarity. Still, tire wear stunk and performance was really good only the first two sessions then dropped from there. The 4th and 5th sessions were a bit worse and the 6ths was just awful.

Also keep in mind I ran with VDC on at TWS since it is rarely needed there and almost never interferes. At COTA it was necessary to turn it off. I think perhaps I drove smoother at COTA for this reason whereas at TWS with the nannies on I could drive it without as much worry.

Lastly I did not do a initial heat cycle to break-in the tires in either event.

Any insight into this wear is appreciated. I suspect I'll be told t deal with it, but even at the very cheap price I paid the tires still cost a lot. I'd like to extend the life of these puppies...

Other notes:

Tires are 315/680-18
Square setup on 10.5" wheels
Hot pressures were 37-39 psi after a cool down lap and a few minutes to park
Ambient temps were nearly identical at both tracks

 

[ehyman]

I just started running racing slicks in January for the first time since I got my car in 2008. The first time was at Circuit of the Americas in January then again early February. I did a total of three days and 15 sessions. The wear and performance results were pretty good. The outside of the tire wore a little more but tire temps generally were pretty even across the width of the tire are each session. Tire pressures generally were in the high 30psi range. After those three days the tires still have some tread left and will be even more usable if flipped.

FF to this past weekend. I went to Texas World Speedway, a track I know very well. I ran brand new slicks to start the event and the wear results are disappointing. I ran only three sessions on day 1 and only three on day 2. I even flipped the tires after the first day. One of the tires corded after the 6th session and the other don't look so hot.

COTA is a butter smooth track and brand new. TWS is an old track with a lot of rough spots and bumps. I also drive TWS harder because of its familiarity. Still, tire wear stunk and performance was really good only the first two sessions then dropped from there. The 4th and 5th sessions were a bit worse and the 6ths was just awful.

Also keep in mind I ran with VDC on at TWS since it is rarely needed there and almost never interferes. At COTA it was necessary to turn it off. I think perhaps I drove smoother at COTA for this reason whereas at TWS with the nannies on I could drive it without as much worry.

Lastly I did not do a initial heat cycle to break-in the tires in either event.

Any insight into this wear is appreciated. I suspect I'll be told t deal with it, but even at the very cheap price I paid the tires still cost a lot. I'd like to extend the life of these puppies...

Where did the tires cord? What size tires? Unless you are running crazy wide tires, or your car is crazy gutted, 30 psi is likely to low. Ambient temps are warmer now then January. Likely something about your setup is suboptimal and you are overheating and then blistering the tires.

Eric

 

[jmunjr]

Thanks for the input. Tires are 315/680-18. They started to cord on the outside and then after I flipped them basically corded after two sessions though they were close already I believe. Hot pressures were 37-39 psi after a cool down lap and a few minutes to park. Ambient temps actually were nearly identical to that of the runs at COTA, but COTA's track was smooth without lots of camber like TWS(ironically since COTA is in a hilly area).

It may be an alignment issue which is being addressed this week but nothing changed from one event to the other.

 

[ehyman]

Thanks for the input. Tires are 315/680-18. They started to cord on the outside and then after I flipped them basically corded after two sessions though they were close already I believe. Hot pressures were 37-39 psi after a cool down lap and a few minutes to park. Ambient temps actually were nearly identical to that of the runs at COTA, but COTA's track was smooth without lots of camber like TWS(ironically since COTA is in a hilly area).

It may be an alignment issue which is being addressed this week but nothing changed from one event to the other.

Cording the shoulder, need more camber. I'll also assume that you don't have flares so you are running a smaller wheel up front, that's going to pinch the fronts and turn give you less effective tire up front an din turn be harder on the shoulders as well. If you haven't done so already , consider getting some adjustable front arms and crank the camber up for your track sessions.

Eric

 

[jmunjr]

Cording the shoulder, need more camber. I'll also assume that you don't have flares so you are running a smaller wheel up front, that's going to pinch the fronts and turn give you less effective tire up front an din turn be harder on the shoulders as well. If you haven't done so already , consider getting some adjustable front arms and crank the camber up for your track sessions.

Eric

Square setup on 10.5" wheels. At COTA I had more negative camber and temps on the inside of the tread were a bit higher than the outside so I went less negative until temps were even. I'm getting a good race shop to do the alignment this week...

 

[paparazzi]

What wheels are you running on the car now and what offsets?

 

[ehyman]

Square setup on 10.5" wheels. At COTA I had more negative camber and temps on the inside of the tread were a bit higher than the outside so I went less negative until temps were even. I'm getting a good race shop to do the alignment this week...

You actually might fair better with a slightly smaller setup 295's or 305's (Not sure what sizes are available in the slicks, as I mainly consume A6's) as the tires won't be as bulged. FWIW, if you are doing a cool down lap and time for parking before taking temps, you are not measure hot temps, all you are measure is how your tires heat up based upon non-loaded drivng and the padock. Tire temps really are only a good representation of whatever type of element you drove right before taking them

Where it me, I'd ignore your temp data, as your cording data is speaking more clearly, and increase your camber. If this isn't the right answer, you'll find out by cording the inside, but my guess is it will fix your issue. Of course, also make sure you didn't pick up some whacky toe in the front

Eric
.

 

[jmunjr]

Thanks, I actually suspected it might be camber as I adjusted some extra negative camber near the end only to see my tires had already corded. I'm going to some quite a bit more negative camber this next time around..

Regarding the tires I got mine for half price new and bought a bunch of them so don't have much of a choice on tires for now.

 

[icarus]

Run the 295/680 size instead. Make sure to heat-cycle the tires first. Have an assistant take tire temps in the middle of a session (come into pits) while they're still hot to make sure you are not running them too hot. GT-R is a heavy car. When you feel the tires getting greasy you need to back off or end your session, make adjustments (alignment/pressures/etc.) to get as even temps as possible across the tire.

 

[DonRinconi]

J -
This is Wilfrido from TWS. Tried sending you a PM but it says your mailbox is full. You must be quite popular. Anyway, it was nice meeting you and keep in touch!