A quick question have a set of 8" x 16" alloys to swop with the 7" X 16" ones on my P38. The problem is my tyres are new 235x70x16, and the knackered ones on the 8" rims are 255x65x16.
Maths gentlemen Maths 8" = 25.4x8 = 203.2mm or 20.32cm which gives you rim width.
285/75 = 285/4 x3 to give you tyre width so 285/4= 71.25x 3 = 213.75 or 21.375cm tyre width. They'll fit but I think I'd fit wider tyres as they'll look a bit weird having the rim almost as fat as the tyre..