245/60/15's on 15X8 rims

dogbreath said
how about the summit wheel vintiques ralley wheels in 15 x 8 with the 4.625 backspacing.

toolmanmike said
:rofl::rofl::rofl: 15x7's just barely fit.

15x8's will fit, but probably not with 255's. At least not if you're counting on that little bit of sidewall squeeze you'd get by putting them on 15x7's. You could probably run them with 245/60/15's, but, those fit just fine on 15x7's. A 7" rim is actually the "measuring rim" for the factory specs listed for a 245/60/15. So there isn't much of a point.

Also, you have to pay attention to what you're doing with the backspace. A 15x7" with 4.625" of backspace has an offset of +16. A 15x8 with a 4.625" backspace has an offset of +3. What that means is that you moved the centerline of the rim a full 1/2" outboard with the 15x8 compared to the 15x7. If you want the centerline of the wheel to end up in the same place, the 15x8 would need a 5.125" backspace. Of course it gets more complicated if you start considering whether or not the section width is getting squeezed down or stretched out.

68 Coronet RT said
All ready purchased the Wheel Vintiques mag 500's 15X7 4.25 backspace not here yet, installing the Mopar Performance Super Stock springs and looks like I'm going to buy 245/60/15's for the rear. I would like the 255's but just not worth the hassle of buying the offset shackle kit for less than a half inch tread.

It's still going to be very tight to the quarters with the measurements you have.

According to the math, even with 245's on 15x7's and 4.25" of backspace you're only going to have like .35" to the quarter lip if you've got 5" from quarter lip to wheel mount. That's not much, even with super stock springs. But with stiff springs and the raised rear end height it might work. The math is all 2D, I'm assuming that the widest part of the tire's section width is at the spot where you measured- the worst case scenario. If you raise the quarter lip above the widest part of the section width, how much clearance you actually have depends on how much spring travel you get running around on the road.