Crager wheel back spacing question
 

Hey guys and lady's , probably been asked a hundred times but I have a 67 gto , looking to find out correct backspacing for crager ss rims15 x 7 front and 15x8 in back with cooper cobra 235/60-15 front and 245/60-15 on back , summit says 4 inch backspacing on all 4 ? Car is all original with drum brakes all 4 , Thanks

4.5” on the front and 4.75-5” on the rear should do it fine. Good luck, and post some pix!

Thanks , just don't wanna order the wrong ones , thanks for the help

At a bare minimum I would remove the current rear wheels and measure the rear axle width. Unless you are 100% confident that after nearly 60 years the rear end is original to the car and the axles original to the rear end.

Verifying the BS of the current wheels would be easier and then verify the clearance both inside and outside for clearance between the tire and any obstructions.

If the existing wheels are 7" and have 4.25" BS, and 8" wheel would need 4.75" BS to put the tire in the same spot.

I have the wider rear end in my '64, but have been able to mount 255/60'15's on the rear of my GTO with 15x7's with 4.25" BS with no rubbing (5" BS would have been better). On the front, 15x7's with the same BS with 235/60/15's with no rubbing with drum brakes, but very light rubbing after switching to front discs (4.5" would have been better).

I now run 17'x7's and ordered my stock appearing rims with 4.625" BS and am pleased with the fitment with my 17" tires

Stay away from the unilugs

More than likely Cragar SS wheels don’t come with enough backspace.

So you end up with a car that looks cool parked but rubs the tires while driving it.

Big problem with a lot of 15” aftermarket wheels for muscle cars. Shallow backspacing like 3-3/4” or 4” and the only way to make them work somewhat is to use undersized tires, which sucks.

Maybe go for some Weld Draglite wheels. Lots of backspace options in different width ranges. Bonus, they’re a bunch lighter than a Cragar SS.

15x5” with 3-1/2” backspace (11 pounds) and 15x8” with 5-1/2” backspace (13 pounds) pictured below.

You can get Cragar SS in any backspace you want, they just take longer to get because they have to come from the factory.

Just looked at Summit for 'stock' sizes:

CRR-61715 is a 15x7" rim with 4.125 BS - this might work with drum brakes or one size smaller tire.

CRR-61C583447 is a 15x8" rim with 4.75" BS which should work fine with a 245/60/15.

This is based on my personal experience with a '64 GTO with the wider (1968) rear end (both a 10 bolt and now a 12 bolt).