SBDinATL

I am looking to upgrade my Pilot Sport Ribs on my 02 996 cab.

My car is not a daily driver, but it is my only car. I drive about 7000 miles a year. I am looking for improved AutoX performance. Comfort is not a concern as I have the X74 Suspension. Wet traction is a small concern because I might have to drive in the rain.

Factory tire sizes are 225/40/R18 front and 285/30/18 rear.

I can find the 225/40/18 for the fronts, but for the rear I can only find 265/35/18. 265/35/18 was the rear tire size on the 99-01 996.

How would going from 285/30 to 265/35 affect handling?

Joe Weinstein

Yes. For autocross you would lose some rear stick. What are your wheel
widths? I'd recommend the Yokohama Advan Neova AD08. In the rear I'd
suggest their 295/30/18, and in front a 245/40/18. You'll have wider and
much better performing tires. If you want maximum autocross performance
get them from TireRack, and ask them to shave them to 4/32nds. They'll
still have enough tread for pedestrian driving in the wet, but will stick the
best in the dry.

SBDinATL

Sorry my wheel sizes are

8x18 and 10x18

Joe Weinstein

yep. Those Neova tires in those sizes would be excellent. Big improvement.

sjfehr

Probably not a big issue in Atlanta, but Neovas can't be driven in the cold. The disclaimers seemed to imply they'd crack if you tried- it's in the description on Tirerack. There are a couple other good threads in this forum and the wheel & tire on tire selection for autocross, and several other good tires you might want to check out.

Jim Michaels

SBD: Joe's recommendation sounds good, except that the front tire size is about .7" larger in diameter than both your OEM front size (25.7" rather than 25.0"), and the rear size he recommended. It might still work okay, but it might look a little funny with a taller front tire (the front would sit about .35" higher). A 245/35/18 size would be about 24.8" in diameter (very close to your OEM diameter), but Yoko AD08s don't come in that size. Michelin PS2s do come in both 245/35/18 and 295/30/18, and they are lighter than AD08s by several pounds each. There are probably better tires for autocross than PS2s in those sizes, however.

Joe Weinstein

If you want autocross performance, tread-width rules. You could consider the AD08 in
235/40/18 for the front if you wanted a shorter front tire instead of maximum stick.
You could also consider the Bridgestone Potenza RE-11, Dunlop Direzza Sport Z1 Star
Spec, Kumho Ecsta XS, or Nitto NT05. Some of those may be cheaper than the Yoko
Advans, though it may be hard to find suitably wide sizes for your wheels. Recent tests
in GrassRootsMotorsports favored the Kumho XS. They didn't test the AD08 till later
(it'll be in the next issue) but I hear good things from the testers, and one should expect
Yokohama to have improved their AD08 over last year's tested best, the AD07. Any of
these will be better than the PS2 or any of the more pedestrian 'sporty' tires. Given your
description, you want true sports-oriented tires.
One step up from these are the DOT competition tires (barely street legal), some of
which have enough tread to make them tolerable in the wet if you're careful. These
would be the Yokohama ADVAN A048 or the Kumho 700.
Joe

http://www.sfrscca.org/solo2/Results...onship/t2.html
http://www.sfrscca.org/solo2/Results...nship/asp.html
http://video.yahoo.com/video/play?vid=112495

SBDinATL

I was looking at the Dunlops and the Kuhmos and maybe the Falken Azenis, which means I would have to go smaller in the rear.

Will 295/30/18's fit properly on a 10" wide wheel?

Thanks for all of your help and input!

Joe Weinstein

Yes. It's spec range is 10" to 11"

Wilder

The Dunlops will be the better choice of these. Kuhmos XS don't perform well in the wet and Falken 615s are good but the Dunlops have better grip, slip more gradually and provide better turn-in.

sjfehr

When faced with your exact same choice two months ago, I went with the Star Specs. I had to switch sizes to get them for my car, too- went 20mm wider in the front, which really helped dial out the chronic understeer that'd been plaguing me all last year.

The Star Specs been awesome on my Boxster S for autocross, and they kicked some major *** in our last wet event. (I'm almost hoping it rains tomorrow! Equalizes out those r-comp guys ) I did find they're sensitive to pressure, and the performance drops off notably if you let the pressure creep up, so you'll have to be more mindful of heat expansion and bleeding off tire pressure when the tires are warm, but that's going to be true of any tire this sticky.

TAI2

Why not just go to Toyo R888's? Since your car is not a DD and you are looking for traction, go for the Toyo's. You can drive to and from the AX event with them and they are better than any of the above listed tires.

Joe Weinstein

Yep. the toyo is like the ADVAN A048 or the Kumho 700 I mentioned. It does
have enough siping to handle some water, and does have a 295/35/18.

sjfehr

Will he have problems with heat cycling or rapid tire wear with R888s and the others, driving 7000 miles a year? It may not be a commuter car, but sounds like it's still a DD.

Jim Michaels

I'm road driving on R888s now; trying to get them scrubbed in for an AX. They sing to you on the road and their stiffer sidewalls probably provide a less compliant ride than the extreme performance tires previously mentioned. I don't think I'd like them on my only car, even for only 7k miles per year. I also wouldn't try to drive on them through the winter. We're coming close to recommending a separate set of rims/tires for AX. I have 3 sets of rims/tires (one each for street, AX, and track), but, with only one set, I think I'd stick with one of the extreme performance tires already mentioned.