To tangent this thread a bit- tube/tire size matching- The old BMX trick was to run a small a "size" (and remember that "size" in tire/tube labeling is not the same as a measurement) tube that wouldn't go flat during the race. This got the lightest rubber for the quickest acceleration. I totally agree that narrower tubes are easier to mount. But since I do this stuff daily I don't have anywhere the same problems mounting tires that some seem to have. What I have found though is that the narrower the tube (WRT the tire/rim) the greater the chance for a non penetrating flat cause. The valve has a base of "rubber" molded to it. When this is then bonded to the tube there's a double thick section (shaped like a doughnut) surrounding the valve stem. This thicker portion of the tube doesn't stretch the same (with air pressure ballooning out the tube to fit the tire/rim) as the rest of the tube so some stress is at this spot. For riders who get a lot of flats I try to fit the widest tube that won't flap over on it's self when installed. This gets the least tube stretch and the least stress on the tube. Sometimes I will deflate the old tube completely and fold it flat, like a ribbon, and then compare to the new tube's "ribbon" width. This gives me a data point as to how wide a tube was previously in use and by how things felt during the old tube's removal I now have some judgement about how a new tube of a different width might mount up. Andy.