I was down in Tempe this weekend and I did a loop of the Ironman bike course the day before the race. I tried the Mr. Tuffy liners and I didn't get a single flat over 40 miles of rough pavement, pieces of CACTUS, glass, broken wood, and other junk. I'm sure it slows me down a bit, but not nearly as much as changing a tire would have. I may use them for LRRH in June because I really don't want to have to fix a flat.

DH did the Ironman this weekend and he used Slimeliners and he didn't flat over 112 miles.

Alex