presta valves - how do the little 'valve closer' thingies get broken?
a. it takes zero force to open or close them
b. when they are on the wheel, nothing touches them
c. when in a pump nozzle, nothing NEEDS to touch them - air pressure makes them open
it isn;t like schrader that needs to be pressed to open
d. even when in a pump nozzle, if something WERE touching them, they wouldn;t close, and the air would come right back and push the pump handle out.. so you would think nothing ever touches the things..
e. yet - about half of mine are cocked over to one side, and 2-3 times a year, one of them will fall out after pumping and the tube is toast
so what makes them bend, and then what makes them break?
i do tend to never throw them out til the valve breaks or there is a hole at the valve stem base
so maybe mine are old but still..
i don;t use caps usually
and i don;t close them very hard