backspace for 18x10 fr on 79 trans am

[Alponcho]

What backspace do folks run on 2nd gen fronts with Ridetech full coil over (earlier tall pin spindle)/truturn? Also running AERO6s. My measurements are all over the place.

[Alponcho]

I tried the 18 x 10 (275 35) fronts I run on my 70 Formula, which have 6.25" backspace. With no steering stops, the back of the tires just kiss the subframe at full turn. So it would seem that 6" backspace would be about right. At the same time, the wheels extend outward almost to the edge of the fender lip, which to me doesn't quite look right, so a little bit more backspace, maybe 6.5", might look better. I'm leaning toward the second option, knowing that I'll have to extend the steering stops a bit. Just don't know how limiting that's going to be wrt turning radius. Thoughts?

[68Formula]

Sounds like you just need a 255/40 on the front. That's the minimum recommended tire width for a 18x10. On that size rim the section width would be 10.6" compared to a 275/35 which is 11.1 on the same rim. Gets you a 1/4" more room in both directions.

[Alponcho]

Thanks for the suggestion 68. After spending some time aligning the fenders, it looks like the 275s might tuck in just enough with 6.25" backspace. I guess we can always switch to a narrower tire if there are any issues.

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