I think this one ton was born with 7.50x17 singles. I have a 1950 GMC 1 ton that was born with 18" dual wheels. Someone mounted a 17.5 tubeless on the front of the 48. I will replace it with a 17" tube required. Back in the 50's and 60's we used to put 17" wheels on the back of 3/4 tons for weight carrying capacity and more speed. I was lucky enough to find 6 18" tires on Craigslist in Springfield, MO. A friend of mine picked them up, banded them to a pallet and dropped them off at a LTL carrier. The original 17" tires on my 2500HD are about ready to replace. My plans is to put 16" tubes in them to keep the tubes from folding and mount them on the OEM 17" wheels. I think all 15", 16", 17", and 18" tires used on 3/4 and 1 tons of the 50's and 60"s were lock ring type. I think it was only the 20" that was offered in the RH-5° design and they were used extensively by both Ford and GM. The 50's and 60"s GM 3/4 and 1 ton are all 8 hole, but the 18" dual application requires an adapter to get less backset on the wheels.
