Regarding the tires your truck was originally fitted with, I am pretty certain that they were not 7 inches wide. The '48-'52 shop manual shows 6x16 tires as standard for a 3100 pickup. Those tires would have been closer to 30" or 31" in diameter, not 28".
Short, fat tires on 80 year old trucks without power steering make driving a miserable chore. The taller and skinnier the tire, the easier and more pleasant the truck will be to drive. Larger diameter tires also make it possible to drive at highway speeds at lower engine rpm.
Ol' Roy came to me with 15"x8" rims. It was IMPOSSIBLE to steer at low speeds and very hard to steer at higher speeds.
I replaced the horrible 15" rims with 16x6 wheels from Wheelsmith. Those wheels and tires coupled with new shock absorbers made the truck as easy to drive as any other vehicle I own.
These rims allow the installation of 225/85R16 tires which are closest to the outside diameter of the original tires.
1950 Chevrolet 3100 (Ol' Roy)
1939 Packard Standard Eight Coupe (The Phantom) | 1956 Cadillac Coupe de Ville (The Bismarck) | 1964 Ford Galaxie 500 coupe |1966 Ford Mustang (Little Red) | 1969 Pontiac GTO (The Dishpit) I 1979 Ford F-100 | 1976 Ford F-150 (Big Red) | 1995 Ford F-150 (Newt)
