Duster tire size

Jacko,
I was speaking to the section width of the 275R/60/15s I bought. With a 4.25in Back Space tire didn't clear spring at 11.2 section width.
I won't run 'universal spacers'. Can't find drilled 5 on 4 solid spacers.
It's all about back spacing.
Easy to measure drum face to spring and use simple math from there for clearance based on tire OD/Tread width/actual (not advertised) back space.
Section widths vary a little by manufacturer.

I get what your saying. My current tires have a section width of 10.3, while the tires I am considering are 10.7. Seems like they will barely clear with current wheels.
I have BBP wheels, so I might be able to find a 1/4 spacer just to give me some extra clearance if I need it.