Need rim backspacing and offset help

[dave73chally]

Upgrading to 15", looking at 15x7, 4" backspacing, 0 offset. 15x8, 4" backspacing, -12.00mm offset. Planning to run 235/60 front and 275/60 back. I know ideal backspace is 4.5" but having trouble finding cragars in that spacing. Will this fit without any issues? I have a stock 73 challenger with 15" rallyes at the moment.

[Strawdawg]

on a 7" wheel, 4.0" back spacing shouild position it the same as 4.5" on an 8" wheel.  7" on a 275/60 is a bit narrow for the tire

[dave73chally]

Thanks for the reply. What if I went 4.25"bs on 7" front and 4.75"bs on 8" rear. Want cragar soft 8's and they don't have a 4.5"bs available.

[nqkjw]

4.75BS on 8"rim should be perfect.
I've got 4.5BS on 8"rim and had to centre the diff,trim the guard lip a little and machined 2mm off the axle face of the rim to get them to fit nice.
I'm using a 275/60/15 tyre.

[Cuda54]

I am running 275/60/15 on a 8" wide Cragar SS 15" with a 5" back space on the back end of my 72 Cuda. I have smaller tires on the same rims up front.

[dave73chally]

Changed my take on this. Going with  15" cop wheels from Wheel Vintiques. Fronts are 15x7 with 4" backspacing, rears are 15x7 with 4.5" backspacing. Planning to run 235/60 up front and 275/60 out back. This seems like a very common combo but I've read mixed reviews about issues, some have none while others need to trim? Read through the 45+ page tire combo thread but just want to be certain.

Any feedback would be great, planning to place my order today.

[dodj]

Should be good other than the 7" wide rim is kinda small for a 275 tire.  IMO, you should go with an 8" rear wheel.

[dave73chally]

Should be good other than the 7" wide rim is kinda small for a 275 tire.  IMO, you should go with an 8" rear wheel.

My mistake, the rear is a 15x8 with 4.5" backspacing. nqkjw (above) is running the same on the back of his and had fitment issues, is this common? I've seen a ton of posts with this setup on stock suspensions, but have also seen posters with issues?

[Chlngrcrzy]

 

[Aracer]

I run 275/60-15" on 10" wide Billit Sp. 8 hole (5.5"Bs.) Mags,       I have the 1968 housing with DrDiff 1" offset hangars.     Car is a 1974 cuda.        It has +2" rear leafs and .90 stock HD bars.            I just ordered 235/70-15" on the 8" Billits / 4.5 Bs. for the front.        At 27.9" tall in front and 28.3" on the rear.        I hated the way the car handled with 26" tires on the front, it was too much difference and wiggled when pushed in tight turns.        So, in addition I will get more roll out at the starting line, and will get some room to bump the light for some overhang. It adds up at the finish line, to a foot.

[nqkjw]

My mistake, the rear is a 15x8 with 4.5" backspacing. nqkjw (above) is running the same on the back of his and had fitment issues, is this common? I've seen a ton of posts with this setup on stock suspensions, but have also seen posters with issues?

I think it's to do with how square the car was originally assembled.
Some have no dramas.
I know with mine nothing is square even though I know it's never had a repair and was in original paint when I got it.
Just manufacturing tolerances I believe.
mine must have been a Friday car

[dave73chally]

Mounting my 15x8-4.5" rear and 15x7-4" wheel vintiques front this weekend. I'll let you guys know how it turns out and post some pics 

[ToxicWolf]

I just put on the same size wheels and tires except I put 255s on the rear instead of 275s on my 70 Challenger. Will be watching to see how it works out.   

[crash520]

Has,
anyone been able to fit 295's on a 10" rim under a 73 Cuda with not moving the springs inboard or trimming the fender lip???

[Dusty1]

295/50/15 on 8.5 wheels---- no modification.