Well the PREFERRED size is of course the one only Michelin makes (Not sure which) But the other size should work well. To be honest I don't know what size my tires are. Ok The Originals were 235/80 R 225
My New Toyos are 245/75 R 225
The difference is less than 1/2 of one percent in terms of overall circumference per the salesman and he showed me the figures (I do not have them) work well.
I am very happy with them. In terms of size I would be hard pressed to recommend one over the other.. Only recommendation is stick as close to the same total circumference (outside circumference) as possible.
Sir Cumfrance... Biggest knight at the round table.
Note on brands: Mitchlin is better for long haul truckers cause the treat lasts a long long time
Why I switched to Toyos which do not last as many miles? Well they will age out before they wear out and both age out at the same rate.