Happy Valley
Active Member
Someone asked about this on a mountain bike mechanic's forum I'm a member of. Here was one mechanic's reply:
hth
This can happen if the tube is too large for the tire, if the tire is under inflated or if it is a real cheap tube. Make sure that the hole in the rim is the proper size if it's a presta valve, and not too large. If the hole in the rim is too big, it might be designed for the schrader type valve. Also, tighten the valve securely, as you are probably doing... Please make sure the tube size and tire size are compatible & that you have a high quality tube.
hth