I don't think I'd really bother. 245's are about 685revs/mi (30.5" height) the 285's about 639 revs/mi (32.8" height). This difference is a mere 8%, which is 8MPH @100, 4MPH @ 50, 2MPH @ 25. It's never going to amount to anything significant either way driveab... Login to read more.