I was also thinking of going tubeless with my Demo 8 for next year, but most of my riding will be here on the rocky East Coast. How well do these rims (the 05's) hold up to hits from the trail? I was thinking that one or two nice shots to the rim lip, and the air seal will be lost, rendering the concept of running UST pointless. How much damage can these rims take before the air seal around the tire bead is lost? I'm an Am-Class rider, second year racing. I'm not too smooth, but I've only had one really bad flatspot incident at the U.S. Open...I usually run fairly high PSI in my tires, and my old rims were Sun Single Tracks... so what do you guys think? Who has direct experience with the 823 / UST set-up?