There were at least a couple of different wheels that could be correct for a 1936 1-1/2 ton Chevy. The wheels differed to match the tires that were on the truck. The standard wheel was suitable for a 6.00 or 6.50 X 20 tire. The '36 and earlier wheels are recognizable for their very triangular hand holes. According to my 1929-1949 Master Parts Catalog, these are "one year only" wheels.
The full floating rear axle appeared in 1936 for the first time on a Chevy truck. This required a larger pilot hole in the center. The '35 and earlier wheel had a 4-1/4" hole. This was enlarged to 4-3/4" in '36 and remained at this size for many years. Wheels from AD, and possibly later trucks will fit your friends '36 and it is not uncommon to find that this has been done. The additional width and dish can be an issue, mostly on the left front where the tire can rub the drag link when turning to the left.
My 1936 RD 1-1/2 ton Chevy had later wheels on the outboard duals, when I got it. They were the super heavy, 2 ton type which weigh 100 lbs. or more. The truck was wearing 7.00 X 20 tires and the wheels with more offset may have been required to prevent the tires from contacting one another at the bottom bulge when the truck was loaded. This is speculation on my part.
I was lucky to find a pair of NOS wheels which matched my four originals. After much searching for a 7th wheel, I finally took a '35 wheel to a machine shop and had the pilot bored out so I could have a spare. The '35 and '36 wheels were identical except for the pilot hole.
I put 6.50 X 20 tires on the truck because I already had a set of 6 and because Chevy info called for them. I am happy with the look. My speedometer reads about 5 mph slow so the 7.00 tires would have corrected some of this and a simple spacer would have solved the possible issue of tires coming in contact with each other at the bulge.
I am fortunate that my truck has the faster of the two gear sets that were available for 1936. I believe they are 5.43.
One more thing. These wheel use a continuous ring that requires much care and caution when mounting tires. I did this work myself. It is possible to distort the ring when removing it. This increases the danger factor. I am 75 years old and grew up on a farm where my Dad did most of his own tire work. I learned to respect/fear these wheels and always put chains around them in a couple of places when airing them up. I also put air in from the back side to the ring is facing away fro me. Start with a little air and check the ring for centering before adding more air. The wheels and rings should be thoroughly inspected before they are used.
I think you can see my truck by clicking the link at the bottom of this post. I hope all this rambling is helpful. Feel free to contact me if you think I can help with anything else.
Mike
