I've gone to the Michelin 245/70/17. They are 10 ply and will change your speed and odometer approxmately -.04%, about 2 1/2 mph at 70. Changes your gear ratio from a 3.73 to about 3.90. Works for me because I have a trailer behind me about 95% of the time. I got good wear out of the Goodyears, but they kept cracking around the rim. A blowout under load at speed can get real exciting real fast.