15×8 wheel backspace ?

86 GN DDR

Member
Joined
Apr 2, 2014
I'm looking to run a 15×8 rear wheel with 255/60/15 MT. What is the best backspace to get without rub?
Thanks

Sent from my SCH-I545 using Tapatalk
 
I can't speak for what it SHOULD be, but I have unrolled fenders, no frame notch, and airbags in the back. With my 15x8 Weld RTS and 4.5 BS, a 255/60/16 MT Street R will clear (on my car at least). The 4.5 BS is pushing it, though. a 275 tire on those would probably rub.
 
If you're going to push it, there's a 100% chance it's up to your exact car. There's many factors.

First you have to look at how well the axle is centered on the frame (on my car I swapped the upper control arms and lucked out). Then you have to look at how well the body is centered on the frame. I made mine 'perfect' when I did my body bushings. You can look at the fenderwell directly above the axle and notice how flush it is, or isn't with the frame.

Next is what brake drums you have. Aluminiums have a thicker flange and space the tire out another 1/8".


On my car everything is centered. When I widened my stock wheels I added 1/4" of backspace over stock. At the time I had 275/50 BFG Radial T/As, widening the wheels moved the tire centerline out 3/8". With unrolled fender lips and no wheel trim it would shave some rubber off the outside tread, and be VERY close to the frame but still clear.

Now I have 295/50 Cooper Cobras and they are the same actual width as the BFGs with a wider tread block. Same thing with the fender lip kissing the tirej.

I guess I need to find a ball bat and some beers on of these days.
Now I have 295/50 Cooper Cobras that are the same width as the old BFGs.
 
I fully expected my tires to rub but think I got lucky. Like Earl's setup, mine are very close to the frame.
 
Thanks everyone for their input..I might play it safe and just order some 15×7 with 3.8 backspace to elimate any surprises.

Sent from my SCH-I545 using Tapatalk
 
Hey guys after a lot of sole searching and research and feedback with everyone here I've decided to go with 4- GTA 16x8 inch rims and will mount BFG's all round 245/50/16 up front and 255/50/16 out back . My 87 GN is totally stock with stock suspension as well.
I really like the full figured look rather than skinnier up front and beefier out back . Really don't want any fitting surprises. My quick question is this doable without spacers or rubbing ???? Promise not to be a pest anymore :) Thanks in advance for your response(s)
 
you need 4 front factory GTA wheels to fit front and rear without spacers. If you run the factory rear GTA wheels then you will need spacers in the back
 
Also front gta rims have a deeper dish then the rears do which looks better all the way around on the regal.
 
Top