I would guess MPG's would be the same. More tread contacting the ground would make the ATZ last longer. That's only my guess, I've never ran MTZ's.
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-2006 QC Laramie 4x4 Auto w/ billet flexplate, Goerend Triple TC and Transgo, Smarty Revo, S&B, A3k, ATS manifold, Aero 4040XL, KORE springs and Thuren stuff, 35x12.5 Toyo M/T.
-95' Ford F250 4x4 w/ 2001 P-pumped Cummins, 5speed ZF, 100hp jammers, helix2 cam, sportsman springs, S300, front coil/4 link conversion, 35" Mickey Baja ATZ.