VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1937-1945 1938 Chevy Rims

Any one have any idea what an average out of round and out of flat measurement might be on a 38 Chevy rim? I selected 5 rims I plan on using for my Coupe but wanted to check roundness and flatness first before I blasted and painted them. I put the rims on the rear axle and used a dial indicator. On average I saw about .040 in. total out of round (+ .020 to -.020) and about .035 in. out of flat. My setup was a little "shaky" so it may have been a little less. All were close so I assume it's typical? Anyone ever try this and have numbers. Dosn't have to be a 38. They're KH original wheels. Billu38

My experience with old steel rims in general is that runout up to 0.10 in both the x-y and z directions is tolerable at the speeds our '30s Chevys run. What is more critical in my view would be tire design-manufacture-type. Take a close look at the balance weights used on reproduction tires at the next big meet. I've seen 5 ounces of weight on 10 degrees of wheel radius on bias plys but usually less than half that on radials. Big unbalances built into the tire trump a little wheel runout. Now modern cast wheels with ultra low profile tires you might feel that 0.10". Dan

I would think a tolerance of .10" would be pretty rare with the old rims and that shouldn't make a difference.

I would say 90% have at least .030" runout. The antique car tires them selves have a lot of run-out.
The 1957 shop manual states that a wheel should not have more than 1/16" runout.

Thanks Gents...sounds like I'm OK....Billu38