I've just pinch-flatted for the third time in two weeks. It never happens near home and I don't like riding with tools. Are there any innertubes that are better than others? I run 40 psi, by the way, and it still happens. It's those darn sharp concrete ledges! Well OK, maybe my lack of smoothness plays in too, but how else am I going to learn to pedal up over 18"? It never happens when I bunnyhop it... just pedal-ups. I'm riding a £4 cheap-o innertube that i got from my local crappy bike shop. can you please tell me were to get good innertubes from and what are good ones? (a "pinch-flat" is a different name for a flat tyre) thanks scott