Originally Posted by Gdads51
JB - Welcome back sir! According to the GM Heritage Center 1961 Chevrolet Truck Data PDF the screenshot below shows the different specifications for the C/K/P10 trucks depending on the Base or designated RPO for the truck.

Their where 3 different size options, 15", 16" and 17.5" depending on the Base or RPO option selected.

Note: All the 15" and 16" wheels were listed as 5" (5K) wide for the rim size. The 17.5" wheels where 5.25" wide.
Wow. Ask and ye shall receive. Shortest thread ever.

Old enough to know better, too young to resist.