Hello - I'm trying to match up a set of 8.25x20 tires for the rear of a 58 Chevy Spartan 80. I have 2 size wheels and diff. tire brands. I have 3 matching tires which are ready to bolt on - they are on 20x6.5 split rims. I have a nice tire of a diff. brand mounted on a 20x7.5 split rim. It is shorter in heighth (diam.) by about 3/4". Can I assume that's because it's on the wider rim? If, on the other hand, it is in part due to being a diff. brand tire, is there a way to measure it while off the rim to determine if it will air up to a matching heighth on a 20x6.5 rim? Thanks !!


1955 GMC 630, 1959 GMC W660, 1958 Chevy Spartan 80