Its not incommon to be able to get 2 different tyres, even in the same size and they will handle very differently. I found this changine from the Cooper ST to the STT, both in 255/85-16. I also found this when I put a set of Firestones onto a road car - wont use them again either, they were really bad. I tend to think that in all of these cases that it was mainly to do with the carcass construction.

