Well, agressive tires like the MT/R do take a bit off the mpg...and, MTR's are really rock tires that are better in the mud than the AT's, but not as good in the mud as MT's.



The difference between 31's and 32's is not that big a deal as to gearing, except for the extra trimming, its easy enough.

The AT ko's last a long time, and the larger, the longer they last, as they make fewer rpm/mile, etc.

The MT\R's are a bit softer, and wear a bit faster, but most people seem to get about 40-50 K out of them...but I have 75 K on my AT ko's right now.



They are a bit noisier than AT's, but not noisy for an aggressive tire.

If you are mostly doing mud, the Cooper STT's are sweet, and wear well too, for example. The BFG MT's also hold up pretty well, in the 50k range...and both are better in mud, but worse on rocks, than the MT/R.

Food for thought.