presta valves

Julia, I've seen this happen before with some pumps. Hand pumps are notorious as sometimes they are hard to release from the valve, and wiggling them tends to bend and flex the presta valve and then it breaks. A better method is just to give the pump handle a sharp "WHACK" with your fist, doing it in a straight direction, so you knock the pump off in one swift blow. Often you don't have the issue with some floor pumps, since many of them have levers that uncompress the rubber seal. But try the fist method...usually I just have the valve at the top of the wheel (12 o'clock) and give my pump a sharp downward rap, and it pops right off (old bike racer's trick...from an old bike racer! ). The air you hear releasing is simply the excess that is pressurized in the pump valving, none is coming out of the tube itself.

Unfortunately, the bottom line is yes, you probably have to replace the tubes.

Max

Edited by max 2004-05-08 7:07 PM

The little bits you are referring to are the heads that screw into the stem. There is not much you can do about that...it happens. The only way to avoid ripping these out is to slowly work the head of the pump off the stem rather than to yank it off. I have one tube on my bike presently that is sans stem and it is fine; I can pump air in but I cannot take air out though.

Same thing happened to me about 2 weeks ago at a group ride. I was running late and had about 5 minutes so I decided to check the pressure. As I took the pump off the valve broke. Basically there are different qualities of tubes and quality of presta valve. Over time the valve becomes weakened and can break. So, I just invested in a better tube and with a sturdier valve and the problem was solved.

Some other advice would be that when you fill you tires make sure the valve is at the 6 o'clock position and not 3 or 9. The head of the pump can put unneccessary pressure on the valve in those positions.

Good luck!

Crash