I had been running the M-12 front and rear and happy with the tires. Once it was time for a new rear I swithced to the Maxis IT because of the good reports here on TT. The tire hooked up well and wore like iron but it felt tall and heavy. The new S-12's showed up yesterday, and I did some comparisons. On the rim with air the S-12 is allmost an inch shorter. This was a bonus, my WR being a tall bike, this will lower the rear 1/2 inch. I weighed both tires on a cheap bathroom scale (not very accurate at lower weights) and S-12 was 10 lbs., Maxis was 16 lbs. These #'s are probably not very accurate but on the scale and by feel the Maxis is much heavier. With the switch of a tire I get a lower rear end, save several lbs. and should also get a much quicker reacting rear suspension. I am happy.