Wheel question...

[VinnyV81]

Hello,

I have an 87 RX7 that I have been autoxing. Last year I ran the car with convertible BBS wheels. I am looking to go with a wider wheel this year to compliment a set of 225/45/15 Hankook R-S3's. I was thinking of going to an 8" wide wheel since the class I'm running in (SM2) has no limitations on wheel width.

I need to know what backspacing I need for the car. It has a full ISC racing suspension setup on it(including adjustable front bar) and the ride height is setup per ITS rules (5" from lowest point of rocker panel)

I was thinking 5" because I was told that would work on a 7" wide wheel. But I don't know if the extra inch of width will cause problems...especially in the front where I know it will be tight.

Here is the wheel I was considering going with:

http://www.southwestspeed.com/?sec=...sub=15x8, Silver, Lightweight&sssub=5 x 4 1/2

I also have 1/2 spacers and long studs, and I'd like to still be able to use them for setup purposes too.

Thanks for the advice in advance.

-Vincent

 

[xr4racer]

Take your BBS convertible wheel you have already and see what the offset or backspacing is. Measure how much clearance you have to the strut and then take it off and space it out with your spacers or washers to simulate the extra width. From these measurements you can determine what you need. A 24mm offset 7" wheel with a 225/45/15 Hoosier works just about perfect. If your springs are beside the tire and not above it 5" backspacing is about all you will get without getting into the spring or perch. By my figuring you will need a 24mm offset wheel to use your 1/2" spacer or a 12mm offset without a spacer.

matt

 

[VinnyV81]

So I can run the 5" backspacing wheel in a 7" width from that website that I have listed with no problems?

 

[xr4racer]

I run 94-98 Mustang V6 aluminum wheels, they have almost exactly a 5" backspace. 15x7, very cheap (craigslist, junkyards, ebay etc) and weigh around 13 lbs. You do not use a spacer at all.

matt

 

[mbuskuhl]

A 24mm offset 7" wheel with a 225/45/15 Hoosier works just about perfect.

x 2 (for stock fenders)

And if you get there with a +35mm wheel and 1/2" spacer which nets 22-23mm all the same thing.

So I can run the 5" backspacing wheel in a 7" width from that website that I have listed with no problems?

Probably not. A 7" wide 5" BS wheel is +25mm, in theory it should fit BUT many of those circle track wheels require a 1/2" spacer in the front to clear the caliper. In fact, everyone I looked into while wheel shopping required a spacer. Add a .5" spacer to the 5" BS wheel and you are at +12mm, which will now probably cause the tire to rub on the fender and definitely would not be IT legal for fender covering. What you would need is a 5.5" BS 7" wide and use a .5" spacer to get to your +25mm. Good luck finding a circle track wheel in 5.5" BS though. You'll find circle track wheels more on the EP cars since they can have a wider track width with wider fenders, not so much on the ITS cars as it's going to be difficult to find something that fits under stock fenders and clears suspension/brakes.

 

[VinnyV81]

I run 94-98 Mustang V6 aluminum wheels, they have almost exactly a 5" backspace. 15x7, very cheap (craigslist, junkyards, ebay etc) and weigh around 13 lbs. You do not use a spacer at all.

matt

does it matter what style wheel it is?

And your sure this will work on a second gen? I HAD to run 1/2 inch spacers with the vert wheels because they would not clear the sleeves on my coilovers.

Thanks for everyone's help.

 

[xr4racer]

Just get stock Mustang V6 wheels, they are all 3 spoke, they made a few different designs between 94-98 or so. They fit perfect with the 24mm offset, no spacer is needed, no longer studs etc. I have used them for 10 years with 225/45/15 Hoosiers.

matt

 

[VinnyV81]

Only problem with that is that those wheels are so UGLY!!! LOL

I will definitely look into to picking up a set of those if nothing else.