WHEEL BACKSPACING
 

Hi,

Does anyone have the correct specifications for the "backspacing" on 14" and 15" wheels to fit a '66 GTO?

Is it a different specification on the front wheels, with disc brakes?

And I believe there should be more or less backspacing, depending on the width of the wheel, correct?

For reference, specifically, a 15"x7" wheel (which I have)

Secondary, would be a 14"x7" wheel

I am an 'ol guy trying to learn.

I currently have a set of American Torque Thrust wheels, which are 15"x7", but I am not sure of the back spacing. The issue is the 215/70r15 BFG Radial T/A's on the front are rubbing.

I may have to replace them,or at least probably get different front tires, which are practically new!

Your help, suggestions, and advice is appreciated!

Allan

I think 4.25" is the standard backspace. A lot of Torque Thrust wheels are only 3.75"

A 7" rim is measured inside bead to inside bead, and therefore is actually 8" wide to the outside of the wheel. Most wheels would have no offset and half of 8" is 4" for zero offset. I prefer just a little positive offset and I would be happy with a wheel with 4-1/4" backspacing on the front (the backspacing is measured with s straightedge across the back of the rim and a ruler dropped down to the mounting surface). Also if the wheel sticks farther out towards the outside this would be negative offset, and the wheel tucked further in would be positive offset. Your 215/70R15 tires shouldn't rub with either the 4" or the 4-1/4" backspacing so possibly your wheels do have some negative offset. I have run up to a 225/70R15 in front on my '67 so if you have the correct offset the 215's shouldn't be a problem. I prefer to stick with a 7" rim on the front.

The backs get harder to figure out but if your are sticking with 7" rims (again 8" total width) then the 4-1/4" backspacing would be a good fit.