I am buying some wheels from a buddy cheap and want to put them on my 74 Valiant. The wheels are from a 2001 Jeep Cherokee sport and are 15x7 with 5.25" backspacing. How wide of a tire can I fit under my car with out rubbing. I wouldn't be opposed to running a small spacer if necessary to bring the backspacing down.

Man...that's a lot of BS. Regardless if you have to use a spacer or not, I wouldn't go any bigger than 255/60 on a 7" rim, period. Anything larger than that and you will have very bowed sidewalls.

Thanks,
I am hoping I can fit 235/60 all around without rubbing at full lock. But from what I read you cant fit a big tire in the front of an A-body.

Uhhhh..... Those wheels may not fit. If they are the aluminum wheels, the centering hub is too small to clear both the front disc hub AND the axle centering hub. You cant even reliably hog out the inside to fit without weakening the rim to a dangerous condition. I tried these wheels on a Dart project. They would fit the rear with spacers, but then you have lost the very important feature of hub centering.
The steel wheels might fit. I cant remember if they also used the same hub centering design. The backspacing is very deep and really isnt worth the effort. 15x7 steel wheels are easily found on all the Diplomat/Gran Fury/5th Ave cars in wrecking yards all over the country. They have 3 3/4 backspacing, and they fit Dart/Valiant cars with room to spare.

I ran 205/75/15 on a 7" with 4.25 bs stock cop rim on the front/back of my 68dart

in the rear a 7" rim 4.5 bs with a 245/60/15 was just right on the fender lip and at the tire bulge and spring when I went A-body 8 3/4 with large brakes..perfect fit in the center of the wheel tub and about max on tire

they A-body 8 3/4 in my 85 truck,now has 12" rims with the same 4.5 bs and is just right on the tire bulge and spring for A-body axle

i looked at the jeep rims also,didnt think it was worth the effort IMHO

they would deff be on the leaf spring



good luck

Rims will probably interfere with the outer end of the upper control arm. On a 15x7, 4.5" BS is about the limit there with a stock style rim shape. Might get a little more or less with a different rim cross section, but not alot.

As far as tire width, it depends a bit on construction. Some 235s will be OK on a 7" rim, but its not ideal. Check with the tire manufacture's recommended specs.

Edit: agree that the aspect ratio will make a difference. a taller aspect ratio will allow wider tire to fit as others have stated. Whether it puts more effective tread on the ground can be very tire specific.

255x60 is the largest size recommended by tire mfgs for a 7" rim.
I know people run 275x60 but do they know more than the mfgs? I doubt it.

You'll have to run a minimum 1" spacer, 1.25" is better, on the rear for the tires inside sidewall to clear the leaf spring. A 1" spacer will mean you will have to install 1" longer wheel studs. That much spacer is a Mickey Mouse way to make a wheel fit.

Pass on the wheels, they aren't worth the hassle to make them fit. I wouldn't do it even if they were free.