well I put a few hours of ride time on the SI and I must say it held up well. I was riding at a local track ( in the woods that is) lots of rocks, ruts and roots. The 4 wheelers have really chewed it up. There are some straights where you can about click into fourth but there are also tight, twisty sections and lots of steep hill climbs with very little run at them. The friend I rode with is fast, he races a few AMA pro arenacrosses every year, I could barely keep him in sight but I rode well for being off the bike for so long. Anyways, to make a long story short, yes the edge of the tire wore a bit but it was alot less than any other tires I've used. I had great traction everywhere. Also, my friend (whose dad has an 87 KX 500) got me when we stopped and said that he forgot how much roost a 500 threw. I like this tire, a good choice for eastern woods type riding.