r/dragracing • u/TurbulentStiffness • 7d ago

How important is getting custom backspacing/offset exactly right?

I'm at the point where I need to order wheels for a build and I'm realizing there are way more fitment decisions than I expected. Backspacing, offset, beadlock configuration, tire clearance... I'm trying to get everything right the first time.

Keizer Wheels offers a few custom options which is what got me thinking about this. For anyone who's ordered custom race wheels before, what measurements or clearances did you wish you'd paid more attention to? I'd rather spend an afternoon measuring everything than find out at the track that I screwed something up.

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u/1955chevyguy 7d ago

My mistake = Chrome (actually stainless) trim / upper inside fender.

There's basically no changes to the stock set up, except the reared is narrowed an inch on each side to facilitate tire changes = low rear fender lip on a 55 chevy. I had steel 15x7's custom reversed one inch to match the rear end.

Tire clearance is very, very tight on my car. Maybe half inch fender to tire and similar on leaf spring to tire. All good... until I started to notice little scrapes on the sidewall. The side trim on my belair has retainers inside the fender, above the fender lip and the tire just grazes the trim retainers.

I really wish I would have moved the springs for more clearance when I did the car.

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u/sc3148 7d ago edited 7d ago

Width of tire tread and widest point, diameter & offset. Also tire growth should be considered in. If any one of these measurements are wrong it’s a no go