Contour Enthusiasts Group Archives Forums Modifications Wheels & Tires Wheel questions... offsets and tire sizes and suspension changes

Hey folks,
I've got some questions for the experts reguarding wheels. I'm setting up my SVT for tracking, so I'm doing a fair number of changes, I'd like to know what affects which things, and how critical certain measurements are.

I've already replaced my suspension with koni's and ground control coil-overs. The car was lowered about 1/2" from that- no more as my driveway is pretty harsh.

I am planning on 1) replacing my front brakes, and 2) purchasing track wheels/tires which will only be put on the car when I go to track events.

So.... I've got a few things I want to clarify before moving on this.

First, the brakes I'm looking at purchasing would involve a 12.2" rotor and wilwood NDL calipers. This apparently requires a .27" spacer to fit the stock wheels on the car. I'm assuming this changes the centerline aspect of things- is this going to be ugly from a suspension point of view?

Second, some folks implied in some of the posts I turned up from searches that lowering a car might change the "proper" offset for suspension loading. Is there a way to calculate this change? How significant is lowering the car 1/2", and should this affect what I choose as the offset for the track wheels?

Lastly, the factory wheels are 16x6", and the car comes stock with 215/50R16 tires. When I go to tire rack and look up wheels for my car, the "recommended" tire size for all wheels, whether they're 17x7 or 17x7.5 is 215/45R17. When I go to the hoosier web site, they recommend an 8-9" width wheel for 225/45R17 tires... do the stock SVT's run extra wide tires on 6" rims, or what's the deal here? I would think that by adding an inch to my rim width I would be able to run a wider tire...

Anyhow, I'm just looking to do things "right".

Thanks
--Ross

the stock svt wheels are 16x6.5, i believe. i think u will run into trouble running a 9 inch wide wheel/tire. 8" might give u trouble. basically a 7inch wide wheel should have a minimum of 40 offset and 7.5 should have a min of 42. 8" would generally need a higher offset for no rubbing but if u get it in 42 offset, u can try rolling the fenders to minimize the rubbing.