The pump is working fine on the presta valve on my back tire, but it is not working on the other presta valve. It seems like the the presta valve isn't sticking out far enough out of the tube for the pump to be able to lock in on it. What could be causing this?
The valve stem is too short. Tubes that have presta valve stems also come in different valve lengths. You need a 40 or 60 mm valve stem or a valve stem extender.
If is it a deep V wheel you need a tube with the proper extension for the value, or a presta valve extender. Next time you replace the tube measure how long the value is in mm and get a tube with a longer valve stem.
to apply the adapter, you need to first unscrew the presta valve, then placed the adapter on and pump up the tire, then take the adapter off and tighten the presta valve to close it. I consider the different answer that that's recommended to replace the tubes so as that the presta valve does not come aside. New tubes are inexpensive - approximately $6 or so. you need to purchase a spare, too, merely in case you flat. in case you do no longer understand the thank you to alter the tubes, your community motorbike save can do this for you and clarify the technique so as which you're able to do it your self interior the destiny and sell you the tire levers (and patch kit in case you want) you will ought to do it. reliable success!
