I measure mine inside the bead and they are 4". I have some which measure 4.5"
Tire size if you are going bias-ply which I have (happily) done are 600-16 or 650-16 and radials would be 215-85R16. However my tire dealer would not put radials on my 4" rims as the specs call for a minimum of 6" or 6.5". Having said that there are a lot of old trucks with narrow rims running radials.


1949 Chevy 1/2-Ton
"Sedgewick"
In the Gallery
1989 Caprice