56 sounds right to me for 6 lug stud centered Budd wheels on Chevy, 2 ton then. Guessing that after 59 the same 6 lug pattern was then also used on 1.5 tons?

I think that 56 is also the first year for the optional tubeless tire.

Would be great to have an answer form someone who knows these details exactly, I am no expert on these "new" trucks.

Grigg

•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
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"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-