QUOTE (Chase266 @ Jul 16 2012, 10:27 AM)
I always use 1.5 tubes for 1.75 and up tire widths since they are lighter and air up to size well. The lighter tubes are of course more prone to flats because the rubber is thinner but as long as you keep them full of air they hold up well. I check my tires everytime I go to the track. You can also put a little baby powder on the inside of your tire to keep things smooth and no chafing issues causing flats. If you want to go crazy with the weight like the one guy said you can make an 18" tube work in a 20" but it is stretching it thin. I personally wouldn't trust it on todays tracks where we are all running really high air pressure and paved turns allow you to hold a tight line at high speed. For example I would never try that at Lousville haha.
Specialized makes a 20 x 1.0 - 1.5 tube that is pretty light, and durable from my experience. Ive seen em in presta and schraeder valves also, although their webpage doesnt show the prestas anymore. 0.8 mm thick so they are kind of in between lightweight and regular thickness tubes. I have good luck with these on the race bikes.