I've never had an issue with flatting on the Ultra Sports, save for one time I ran over a screw that went through the sidewall and tore the bead. They are not very lightweight, nor do they roll very fast. They don't seem to get cut up as easily as other tires I've tried (Kenda Koncept, Maxxis Detonator, Vittoria Diamante Pro, Schwalbe Blizzard Sport).