how much clearance from the frame should there be?

[slone56]

I am about to get a larger tire for the rear. As a general rule what clearance should I maintain from the frame? Thanks

 

[SafariWagon]

I read somewhere 3/8 of an inch for 17 P275/40 tires is what somebody was running. I think it would depend on the size of wheel. A 15 inch wheel has a taller tire, so the tire would tend to "roll" over more, hence needing more clearance than a 17 inch tire would. Less side wall = less tire "roll".

 

[85 Cutlass Brougham]

It will also depend on your rear suspension. If you have 25 year old rubber bushings that are cracked and dry rotted, expect some flex to allow the wheels to touch the frame under hard cornering. If, however, you have upgraded to a more solid rear suspension like spherical bearing LCA's you could probably get away with more.