Bicycle Mechanics - Tire pump slips off needle

Never had this problem before on the same type of tires tubes. But everytime I attach my pump to the needle of the tire and lock it, after one or two pumps the pump head pops out. I try to get a 100 - 110 psi on my road tire and can't get past 85 or 90 Needle on the tire is smooth. Am I just having a bad day? I want to go riding :confused:

There is a rubber cylinder inside the head of the pump. If the pump has a
double sided head, one for Presta (narrow) and one for Schrader (like auto
tires) you can try either pushing the head of the pump very firmly onto the
valve before flipping the lever or if not successful, take the rubber cylinder out and reverse it. Repeated use converts the inside of the cylinder from a round
to a conical hole which doesn't grip as well. In theory these are replaceable but in practice repair parts are hard to find. Also on Presta valves, as you
know you have to unscrew the end screw on the valve, sometimes the valve
sticks and will blow off the pump head from high pressures. Always pop the
end of the valve after you unscrew it which your finger and let some air out to
make sure the stem is not sticking. This is the most likely reason for popoff.
Steve

....this is what I have to do from time to time.....

Is there a lever lock on that pump head? Can't tell for sure but it looks like the
friction fit Silca head I used to use in the '70s. If so I suggest a new lever lock head. Steve

Originally posted by sch
[B...... it looks like the
friction fit Silca head I used to use in the '70's......[/B]

it sure is.....

If your runnig presta valves make sure the little round threaded nut on the stem. This prevents the valve stem from being pushed into the rim when you push the pump head on and allows you to push the pump head on farther.

There are lots of after-market pump heads out there. The Topeak Smarthead is pretty slick. If you only use the pump on presta tubes, you can just get one of the little brass jobbies.