michaelkrelina

I would appreciate a feedback on these two setups for autocross. In both cases I would use stock rear Speedline 18x10.5 in all 4 corners.
Any alternate suggestions for the same wheels and for max performance?
Mike

froggy47

Just the a6 is stickier & will not last as long. Is cost a factor for you?

Davinss

If you really care about max performance why not go with a staggered setup?

michaelkrelina

How to stagger & maximize performance without tubbing or otherwise irreversibly altering the body of the car? The only way I know how to is to decrease the amount of rubber in the front, eg 295-35/17, 295-30/18 etc.

I believe that I can use adjustable sway bars and alignment adjustments to maintain balanced handling with square wheel size at the lower speeds of autocross. (I do not believe that I can do that at higher speeds at the track! My track setup is staggered!)

Mike

michaelkrelina

To keep the wear of Hoosiers down I thought I would use my track R888 part of the time and use Hoosiers when it really matters, in order to have them last longer. I want to experience the high performance, at least part of the time. Having access to this experience is more important than winning the season.
Mike

TedDBere

Using the 18's upfront will bump you out of stock class and into ASP and you won't be competitive with those cars. Many of them run 17's in the rear with 335s to get better gearing.

I'd stick with the 17s in the front and run either the 275 Kumho or the 295 Hoosier.

What else have you done with your car?

Good luck.

Wah

I used to run 315/30/18 Pirelli PZero Corsa on all 4 on my '03 Z06.

froggy47

I have my first set of a6's now & I will be lucky to get 40 runs on the fronts. And I flip & reverse direction & I am not hard on tires. Prolly get 60 runs on rears.

YMMV

mountainbiker2

If your going to run Kumho's, I would use 315/35/18 rear. 305/30/18 front. Hoosiers 315/30/18 on all 4 corners. You could rotate the Hoosiers real easy too.

Steve

Davinss

A larger tire up front won't necessarily give you better performance. In a 30 second autocross run the larger front tire you go with the harder it's going to be to get it warmed up.

A warm 275 will have tons more grip than a cold 315.

TedDBere

You should do a lot better than that. My last two sets of A6s went over 120 runs and I tossed them with life left in them for new A6s. The old Hoosiers would cord around 60 runs.

Z06Fix

Wow.... thats crazy! I have 60 runs on a set from last year and they still have probly 40% left on them. What pressures are you running? Also what type of pavement? I know if you run on concrete all the time it will really wear them out quick.

Z06Fix

ASP was won last year on V710's. I think it really comes down to what the driver feels more comfortable on.

froggy47

True for the 1st run, but thereafter, I like BIG fronts.

froggy47

Ted & Z06fix,

I only wish they were lasting better. I've been running then about 32/29 (based on info from a Nat Champ who runs them on her c5z)

West lot SD 40 year old asphalt, tour coming soon. I JUST flipped them after about 22 runs to put a good edge outside.

The middle (between the grooves) is wearing the worst. I don't slide around very much, try to be smooth with early & lesser inputs.

These are 2008 build date - very fresh when I started using them around 7/08.

I drive rt 50 miles to event with 40 psi.

The wear pattern show a "feathering" if you know what I mean, at the grooves.

Maybe I can post a pic, but not tonight.

Thanks.

michaelkrelina

I've lowered the suspension, use 18x10.5 wheels x4, have a racing seat and harness, plan to use better brake pads and I'am deliberating over a swaybar upgrade (Pfadt Competition?) I only participate in local events in Ottawa, Canada and locally will be in the top class, no matter what I do or not do with my car. I don't want to spend a lot of money or alter the car in a way that is difficult to reverse before the eventual sale.

michaelkrelina

Do you think Kumhos have greater longevity? How much do you sacrifice in performance with Kumhos on a 60 second course? .05 seconds ?? ... more ... ???

eschantra

I run V710s and was about 1.5 seconds slower on a national course than a similarly set up car with A6s. Part of it was me (read, it was my first national event) but part of it was the fact I was getting understeer with a 275/315 combo, to the point that I was catching a little sidewall on both fronts at 38psi with -2 degress camber. It didn't help that the course had two long decreasing radius turns. I'm going to try the 295/40-17 V710 on the front and hope it doesn't rub.

michaelkrelina

Have you checked the diameter of 295/40-17 vs 305/30-18. The 305 has a smaller diameter and probably does not represent a larger risk of rubbing, however, it is a square rather than rounded profile and probably will need a large negative camber if used in the front. By the way your 315 in the back, is that 315/35-18? Does that fit well and rub in any circumstances? How much is your car lowered?

froggy47

Yes

I also find a6 faster by about 1.5 sec.