Bob M

Sorry if this horse has already been beaten senseless. I searched the forums though and couldn't find any current info posted. Given that tire technology changes so often, I wanted to tap into any new info the autocross experts might be willing to share. I have done quite a few DE events but never autocrossed my TT. Knowing that the tire needs are quite different between the two kinds of events, can anyone set me on a good path? I would like to get a set on my spare rims before next weekend. Thanks in advance -- appreciate any advice/help that is offered.

Bob

MechanicalEng

Hoosier A6

Joe Weinstein

Yep. Only two in possible contention, the Hoosier or the Kumho 710. If your alignment is
good and aggressive, the Hoosier will be the best when it's on, and while it lasts. The
Kumho will last a lot longer and can even be driven to/from events (in the dry). Neither
will last long when driven in conditions that don't match the camber (doing any hard
cornering without sufficient camber, or doing any commuting with a lot of camber).
Some regions have street-tire classes (wear rating 140 and up), which makes it easier
to arrive and drive. Then there are a different range of tires, and not so far down from
Hoosiers and you'd think nowadays.

Bob M

Thanks for the feedback, ME and Joe. I appreciate it!
Based on your advice and my situation, I am thinking to go with the Kumho V710's. In looking at the Tirerack site for sizes, I see there are some options that might work. Given the AWD with our cars, it seems like the best combo would be to use 245/35R18 (88W SL Squared Shoulder) on the front and the 305/30R18 (97W SL Squared Shoulder) on the rear though. Am I right on this? Wonder if the 245's will rub on my inner fender liners? Thanks again for the help!

Joe Weinstein

245/35R18
285/30R18

I wouldn't run the 305... too much diameter difference.

Bob M

Should have asked about brake pads and fluid. I have been using Performance Friction Carbon Carbon pads but they really need some heat in them to work their best. Given Autocross is one lap, I don;t think they would be the best choice for this application. Any suggestions here? I'd take a suggestion about what brake fluid you guys recommend too, if you don't mind. Thanks again for the help!

Bob M

Thanks, for the tire recommendations, Joe. Any thoughts on pads and fluids?

Joe Weinstein

You shouldn't be putting your brakes through much work in autocross. If your brakes
work well enough to trust in the street first thing in the morning, you'll be fine. Some
gonzo autocrossers even put on smaller brakes for the weight savings.

Bob M

Makes sense. Thanks.

MechanicalEng

I always use the stock pads for AX an they work fine, if you dont trailer your car to the events you could also try the Nitto NT-01s I have used them and they are very good, 245/40 and 305/30 will fit if your car and they wont melt your center diff. , as far as alignment I run Max camber up front (-0.6) and close to 0 toe up front, I leave the back at stock settings.

Bob M

Thanks for the additional info ME. I went ahead and ordered the Kumho's (heat cycled) from Tirerack, as from what you said they wouldn't need a bunch of negative camber to work well. For now, I want to keep my alignment settings as is. I also bought some Textar pads from Kevin, so pretty much a stock pad.
Re tire pressures, any numbers I you guys recommend I should start off or go with?

Thanks again for guiding me along here. I feel confident with my choices so far because of it.

Joe Weinstein

start with 36 front, 44 rear, then chalk your sidewall, and adjust so there's no scrub more than about an 1/8th inch or so onto the sidewall.

doubleurx

What about the Kumho Ecsta XS. 180 Tread wear rating. They should be great for AX in 235f, 315 r.

Joe Weinstein

the XS and Yokohama AD08 are among the best street tires, but not
able to compete with Hoosiers and Kumho 710s which are essentially
slicks, with softer rubber.

doubleurx

Won't the Hoosiers and 710's affect your run class though?