Airing up a road bike tire?

R

RACHEL

New member
I have a road bike with a presta valve and am apparently doing something wrong when airing it up. I remove the cap, unscrew the valve as far as it goes, put it in my air pump with a presta valve adapter, and lock on the pump. When I pump the air though, it blows right back out of the tire and won't fill. Any ideas what I might be doing wrong? Thanks!
 
The most likely cause is that the pump head isn't installed far enough nto the valve stem. You may also need to give the open p/v a tap before you install the pump as it may be sticking. If neither of these are the case, then the grommet inside the pump head may not be sealing properly. The possible causes could be: a. worn grommet
b. it's a reversible grommet and is installed
with the schraeder side out and needs to
be reversed.
c. The retaining nut on the end of the pump
head(if there is one) needs to be tightened
a little so that the grommet is being com-
pressed enough to seal. It can be done by
hand.
 
Do not drill out your rim to use a shrader valve it will weaken the rim. When you unlock the presta valve push down in the stem to let a little air out and unseat the seal. Screw on the valve adapter and then attach the pump. There shouldn't be any air leakage from the valve, adapter, or the pump.

http://bicycletutor.com/presta-valve/
 
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