Dedicated Track Tires

ChrisSlicks · 11-03-2009, 08:28 PM

Not at all.

I currently run 275/35 front and 305/30 rear on the stock wheels. There is an unbelievable amount of room remaining around the wheel. The tightest point is the inside of the front wheel against the vertical control arm piece when you push a lot of negative camber. This can be corrected by running a different offset wheel or by using a small spacer. I run -2.5 front camber using the SPC upper control arms and there is a monster gap between the outside edge of the front wheel and the fender.

Nikon FM · 11-03-2009, 08:37 PM

^ +1 good info. Thanks!

ChrisSlicks · 11-03-2009, 09:07 PM

No problem, good luck at the track!

Nikon FM · 11-04-2009, 08:25 PM

How does the traction control system like the 265/295 ratio? I am at the point where I'm going to turn the "baby sitter" off during track days, but have heard some cars have difficulty with different ratios than the OEM setup.

JoeD · 11-04-2009, 08:34 PM

Quote:

Originally Posted by Nikon FM

How does the traction control system like the 265/295 ratio? I am at the point where I'm going to turn the "baby sitter" off during track days, but have heard some cars have difficulty with different ratios than the OEM setup.

Tire-width has nothing to do with the operation of traction-control. So long as the tires are properly sized in terms of diameter (as close to stock as possible), there is no reason for anything to malfunction.

Nikon FM · 11-04-2009, 08:39 PM

Quote:

Originally Posted by JoeD

Tire-width has nothing to do with the operation of traction-control. So long as the tires are properly sized in terms of diameter (as close to stock as possible), there is no reason for anything to malfunction.

Pretty much holding up the track newby sign here. Thanks!

ChrisSlicks · 11-04-2009, 08:39 PM

Because you are using these as track tires with the VDC turned off I wouldn't worry about it too much. The size differential is really only a problem for the traction control, with it disabled it doesn't intervene until the speed difference between front and rear is huge.

For daily driver tires you want the size differential as close as possible, within 2% front to rear.

With the R888 sizes listed your differential front to rear will be 2.3%.

rbratton · 11-04-2009, 09:25 PM

Quote:

Originally Posted by ChrisSlicks

Because you are using these as track tires with the VDC turned off I wouldn't worry about it too much. The size differential is really only a problem for the traction control, with it disabled it doesn't intervene until the speed difference between front and rear is huge.

The isn't exactly true. The tire diameter difference effects your ABS which cannot be turned off. The computer might turn it off if it detects an issue; then again, it could just damage your abs system. You are correct tat 2% difference in diameter front to rear should be acceptable for the ABS system.

ChrisSlicks · 11-05-2009, 08:58 AM

Quote:

Originally Posted by rbratton

The isn't exactly true. The tire diameter difference effects your ABS which cannot be turned off. The computer might turn it off if it detects an issue; then again, it could just damage your abs system. You are correct tat 2% difference in diameter front to rear should be acceptable for the ABS system.

The ABS should be handle even more than 2% theoretically, perhaps 4 or 5%. Unfortunately discovering it's true thresholds would require insider knowledge of it's workings or lots of empirical testing.

11-03-2009, 08:37 PM	#2 (permalink)
Nikon FM Track Member Join Date: Jan 2009 Location: Snoqualmie WA Posts: 973 Drives: 03 996TT Porsche Rep Power: 608	^ +1 good info. Thanks! __________________ Buddy Revell: "One man's sooner is another man's later"

11-04-2009, 08:25 PM	#4 (permalink)
Nikon FM Track Member Join Date: Jan 2009 Location: Snoqualmie WA Posts: 973 Drives: 03 996TT Porsche Rep Power: 608	How does the traction control system like the 265/295 ratio? I am at the point where I'm going to turn the "baby sitter" off during track days, but have heard some cars have difficulty with different ratios than the OEM setup. __________________ Buddy Revell: "One man's sooner is another man's later"

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11-03-2009, 08:28 PM	#1 (permalink)
ChrisSlicks A True Z Fanatic Join Date: Mar 2009 Location: North East Posts: 6,203 Drives: 09 370Z Sport M6 Rep Power: 655	Not at all. I currently run 275/35 front and 305/30 rear on the stock wheels. There is an unbelievable amount of room remaining around the wheel. The tightest point is the inside of the front wheel against the vertical control arm piece when you push a lot of negative camber. This can be corrected by running a different offset wheel or by using a small spacer. I run -2.5 front camber using the SPC upper control arms and there is a monster gap between the outside edge of the front wheel and the fender.

11-03-2009, 09:07 PM	#3 (permalink)
ChrisSlicks A True Z Fanatic Join Date: Mar 2009 Location: North East Posts: 6,203 Drives: 09 370Z Sport M6 Rep Power: 655	No problem, good luck at the track!

11-04-2009, 08:39 PM	#7 (permalink)
ChrisSlicks A True Z Fanatic Join Date: Mar 2009 Location: North East Posts: 6,203 Drives: 09 370Z Sport M6 Rep Power: 655	Because you are using these as track tires with the VDC turned off I wouldn't worry about it too much. The size differential is really only a problem for the traction control, with it disabled it doesn't intervene until the speed difference between front and rear is huge. For daily driver tires you want the size differential as close as possible, within 2% front to rear. With the R888 sizes listed your differential front to rear will be 2.3%.