Glad this got bumped. So far this year I have 8 flats on the Challenge tires, a couple were my fault for not getting the glass out of the tread. Anyway, I've learned that they really are more flat prone than some other tires. I'm not 100% sure I would say they are worth the extra cost and hassle, but they are pretty nice. Changing a flat is a snap now, I can do it in 10 minutes or less with no problems.