68 cuda tire size

[redfastback]

i have looked and can't find what the widest rear tire on a 15x8 rim was. i thought i remembered a thread that mentioned it but i can only find dart, duster ones. what backspacing? this is bbp.

 

[AdamR]

a 255-60 will fit with 4.5" back spacing. a 275-60-15 should fit with a 4 or 4.25" back spacing or if you use the offset shackle kit they will work with a 4.5 or 4-7/8" back spacing I wouldnt go bigger then that on a 8" rim.

 

[AdamR]

Those are M/T drag radials, 275-60-15s on a 15X8.5" rim with 4-7/8" back spacing. My springs were moved in to the frame but the offset hangers would have been enough. Stock wheel wells.

 

[redfastback]

thanks adam. i am planning on 15x8 or 8.5 cop rims for the rear. i have stock 15x7 cop rims now but want more rubber. i am not tubbing or moving the springs or even the offset shackles. so it looks like 255/50 or 255/60 is the biggest. so...4.5 " backspacing?

 

[AdamR]

15X8 with 4.5" backspacing and a 255-60 will fit nice. I ran 255-60s before I mov1ed my springs. My rims were 4-7/8" backspacing and they were close to the springs so 4.5" should be perfect.

If you want a stickey drag radial M/T sells them in 255-60-15

 

[GT340]

Here's what I did when I had my rims made:

Take off the wheel. Set the axle on a stand that has the axle at ride height. Run a plumb from the spring, a plumb from the rear drum face, and, a plumb from the inside lip of the fender. Take your measurements and you'll know how wide a space you're dealing with, and the correct offset. I recommend doing both sides to ensure that one side isn't a little different.