One word review: "velcro" I put a Dunlop 803 on the rear of my '04 WR450 last week. 8 lb of pressure, two rim-locks, stock rim, and a heavy duty tube. Mounting wasn't any harder than a normal knobby. Tried it out on some tight rocky/sandy single-track in AZ (Rattlesnake Ridge, Indiana, Otero, Dagger, and Pickaxe for the Phoenix guys). When I came to the first series of uphill rock ledges, I gave it plenty of throttle (as it usually involves plenty of spinning and floundering on the way up). But the 803 stuck like glue and launched myself and the bike over the entire series of ledges. And no, I didn't stick the landing. Impressive traction. The tire was also great on hills that have decomposing rock (kind of like sand and marbles mixed together). Normally I have to hit the approach at speed or have no chance of making it. With the 803 I could tractor on up, or even stop midway and restart, making it up the hill without any tire spin. Pretty sweet. Rode down a creek that was full of big wet rocks. Tire stuck without much sliding. Feet didn't touch the water once. Dry boots are good. I was really surprised by how well it performed in deep powdery sand. The tire doesn't dig a hole like a knobby, but seems to just float on top of the surface. Couldn't roost around the corners, but had a very controlled, stable feeling in the sand. Smacked the 803 into lots of rocks and ledges going fast, but no problems with pinch flats. I was really leery of running such a low pressure (especially on a heavy WR), but it doesn't seem to be a problem. The best thing was that I rode nonstop for 3 hours and wasn't exhausted afterwards. After doing the same loop with a knobby I'm usually ready for the morgue. I spent much more time just riding and less time getting unstuck or fighting over obstacles. Overall its a great tire for technical riding. I think I'll still use a knobby when racing in non-technical conditions, where getting traction isn't an issue. Two great big thumbs up.