rwerk91

Alright, quick rundown of setup. Front 235/45/17 rear 315/35/17. Front and rear QA1 coilover conversion. Wanting to eventually get wider front wheels and tires for better turning grip at least 265 preferably 285+. My question is if in the mean time I use a 1" bolt on adapter up front will this improve or simulate a little by widening the front stance? Essentially running flush with the fender. Is this logic/thinking all off or will this work for the time being. Thanks

Tibo

iTrader: (15)

My knowledge is not all inclusive, but from what I have felt and understood is that if you are want the best performance out of your wheels/tires for autocross then you should stick with the same size wheels/tires in front and back. Skip the staggered sets. Your car will handle more neutral and be slightly more predictable in turns. 275s will fit up front and out back without issue, 285s can work on an 18" rim and perfect backspacing. 295s on an 18"rim can work but it is even more precise of an exercise. There are a few threads on the wheels and tire board about 285 and 295s up front on 18"rims. 275/40 is as big as you can get on a 17" before bumping the tie rod or fender. Over the years I have run 3 different sets of staggered rims on the Camaro before finally switching to a non-staggered set. From a handling perspective I should have done this years ago. The wider tires up front will help with braking also as we do not posses ABS.

You could run a wheel adapter but I think 1.25" is the thinnest you can go to clear the stock length wheel studs. Some cars have the wheel studs where the threads don't start until after the first 1/8" if yours don't you may be able to use 1" adapters. You may need to roll the fender lip a little bit to ensure on hard turns you don't rub a sharp edge on the tire though (if they stick out that far and the car is that low).

GCrites80s

Cars that come with staggered tires such as Corvettes have had the chassis tuning engineered for them. Ones that don't have not. If you want to run staggered tires you can tune your car for them with sway bar rate, springs, corner weighting, brake bias etc. Otherwise run your tires square all around.

plum92_camaro

I agree with tibo. you want a balanced set up of at least 275's all the way around. The new 1LE's come with 275's all around but wider wheels in the back. Makes the back tires sidewall look funny up close.

I did run across a thread once where a guy was at a track day and wore out some of his tires and ran some narrower tires on the rear to finish the day. He said the car handled better than before with matched tires. I'm not recommending to try that cause every car is a little different but i wanted to share the story as I thought it was interesting.

Here is a link to that thread i mentioned. http://www.frrax.com/rrforum/index.php?showtopic=16553

Tibo

iTrader: (15)

And those same cars can get away with a 8-8.5 front rim because they have less weight on the front combined with ABS. We have more front end weight and no ABS so we need as much front tire as we can get.

InfernalVortex

iTrader: (4)

Im going to be running a C4 ZR1 setup the rest of this season. Im thinking since I have 275's up front it wont be too big of a deal to have the 315's in the rear. The car already seems pretty tail happy (a very controllable tail happy) which I think is due to the 24mm rear bar (34 up front) being a little too big. But Im wondering if the 315's back there will offset that a little bit.

Im hoping to get them on the car before the next autocross, but it may have to wait until April.

I would rather have had 4 17x9.5's, but this is the set that I found. I can always get another pair of 17x9.5's later, but I havent noticed any for sale in a while... Im hoping to get a set of four 17x9.5's to run used takeoff slicks, since you can find them in 275/40/17 pretty often in decent shape.

Tibo

iTrader: (15)

I purchased mine from OE Wheels, if you just want a 17/18 x 9.5 and a particular look isn't an issue they have some great deals often under $400 for a set.
http://www.oewheelsllc.com/Wheels_3/...4#.Uw7DAvldVDg

InfernalVortex

iTrader: (4)

Yeah I'd prefer 17's, specificalyl ZR1s just because I like them a lot.

Will an 18x10.5 (C5 Z06 rear) fit in the front with a 2.25 inch spacer? Does it clear the tie rod and the strut without having to be pushed out farther?

Edit: I did a search and found this thread.... Wow... this is an amazing car:

https://www.thirdgen.org/forums/whee...s-all-4-a.html

Another example of a fast car with a squared tire setup.

Tibo

iTrader: (15)

I almost went that route but in a different rim. In the end I did not want to do all of the mock up and measuring and then pay return shipping if they did not fit. The rims he went with are pricey.

Eagle223usa

When I went to Strano parts to upgrade my suspension, Sam told me not to buy anything until my tires were at least 10 inches wide. I bought the CTW's and 275/40/17 BFG Sport Comp-2's and they really helped my handling and times. On the rim they are like 10.4 inches wide (IIRC). My next trick may be lowering springs...

paul_huryk

Absolutely correct.

Although don't give regular ABS too much credit - it is only truly effective when tire to road grip is compromised - like wet or snowy conditions. It can't increase braking grip - only maximize what is available.

Being involved somewhat with BMWs, I can tell you that even they respond favorably to more front tire, even with 50:50 weight distribution - in both handling and braking. Square tire setups don't get the crdit they deserve - although on older musclecars with limited front tire clearance still do pretty well.