I'm looking at moving up from my stock 17" wheels and was wondering if anyone had thoughts on the best size(s) for performance. I have a casual interest in autocross & may eventually want to do some track day stuff, but nothing incredibly serious right now. Currently my '06 GT is stock ride hight, though I might do a 1" drop in the not too distant future. Other suspension is stock, though I plan on adding adjustable front & rear sway bars in the very near future.

I'm looking at either the GT500 or AMR wheels at American Muscle - though if I decide to splurge I could save some wt. by going w/the TSW Nuremburg ones. Was wondering if I should go w/18" vs. 19" and how much the wheel width would be a factor. Would staggered be a good thing or not? I know each option has it's pros, cons & trade-offs, I'm just not sure exactly what they are & how much they matter.

Any thoughts, assistance is appreciated. Thanks.

- Neal

 

Both are good. There's more selection of performance tires in 18" right now, but the manufacturers are starting to produce some good 19" sizes. Also, 18" tires are generally cheaper than 19" for the same tire.

Ride comfort will probably be better in 18". The larger sidewall helps cushion the bumps better.

However, I have 19"'s on mine, and they work well.

 

For autocross your wheel choice could be determined by which class you wish to legally run in, which may already be defined by any other mods that you might have done (such as a tune).

You don't want to run a staggered setup - the front end is the heavy end so it has to do relatively more of the job of getting you turning, so you want as much tire there as you have out back (until you're running forced induction, anyway).

Wheel width is more important than wheel diameter - it's where stability and support for the tire treads ultimately comes from. Assuming that class restrictions are not an issue (or that you're running mainly for fun and don't care where they class your car), I wouldn't run anything narrower than 9", preferably 9.5" minimum. Nor would I stagger the wheel widths, at least not unless crowding as much wheel as possible under both ends of the car was seen as necessary.

But don't forget to consider offset. The wider you go, the tighter the range of offsets that will work without rubbing either inside or outside gets, and beyond some width (maybe 18x10?) you may having to run greater negative camber, or thin spacers, or live with other compromises.

If it helps any, I'm looking at an 18x10.5, +38 (Enkei) with probably 285/35-18's for track days, and for any autocrossing I might do just run in whatever the car fits, which isn't F-Stock or F-Street as it sits anyway (might be all the way to CP). Anyway, that combination should be about even with the 1LE Camaro's wheel/tire package, all things considered. Maybe a little better with the right brand and model tires.


Norm

 

Listen to Norm. He's "da man".

 

Thanks. Due to the functional CDC Shaker she came with I'm in ESP anyways (I've been told if one really wanted to be **** they could call it a vented hood & put me in CP, but this is just local stuff), so that does free me up a bit. I was figuring I'd want the widest tire possible. Prob. would lean 18" just due to the other aforementioned offsets (esp. if/when lowered). Also, how big of a factor do you think wheel weight would be in performance?

 

Some years ago the effect of wheel weight on autocross run times was investigated - tested, actually - and the results noted in the SCCA member magazine. Going off memory here, the effect of a 5 lb difference per wheel on a Miata over a ~45 second course was estimated to be somewhere between 0.100 and 0.200 seconds.


Norm

 

Rotating mass does have a larger impact on the overall performance of a vehicle than non-rotating mass. Unsprung mass also has a more significant impact on the performance of a vechile than sprung mass. And wheels/tires are both rotating and unsprung.

If you're ever thinking of spending money to reduce the weight of your vehicles, wheels should be your first target, then other suspension components, then other drivetrain components, then the rest of the car.

 

Norm knows, he's been around the track a few times.

 

Cool. Thanks.