I posted this on MTBR too.. sort of a 'don't be stupid like me' public service announcement:
I'm not sure if others use this weight saving 'trick', but i sometimes would run small (ie. 26x1.5) tubes, overinflated in my tires (1.95"), thinking it would save a bit of rotational weight, and that the tubes would probably be fine getting a little overinflated.
I guess not. I had some mysterious punctures on my front wheel, one of which almost caused a crash on a rocky descent, but i thought they were freak punctures, and just patched them and kept riding. This morning, i discovered that my front wheel had gone flat overnight. I took out the tube, and saw that one of the glueless patches had leaked, so i re-patched it, reinstalled it, and began pumping it up. When i got to about 40psi, there was a deafening bang (my left ear is still buzzing, 20 minutes later), a cloud of talc, and my tube had literally exploded, taking with it some of the kevlar tire bead. My precious vintage Specialized Ground Control tire is ruined.
In retrospect, the previous mysterious flats should have been a warning sign, but i had been using this 'trick' for so long that i never thought it was the culprit. Also, the glueless patch probably leaked because it the butyl tube was probably stretching out too much under it. I should note that this blowout did not occur where there was a patch, but in another place on the tube.
Anyway, just thought i'd pass on the warning. Use the proper sized inner tubes!!
I was just lucky this happened while the bike was on the work-stand, not while riding! (i wouldn't be deaf, but i might have gotten a broken neck and tacoed front wheel)