Sheldon Brown on the types of Wood valves and their differences:
https://www.sheldonbrown.com/inner-tubes.html
Jonathan
Sheldon Brown on the types of Wood valves and their differences:
What plunger? The air valve on a woods valve is at the base of it, and if it's rubber tubing it won't be opened by pressing a plunger. I've not checked if the valve on the more modern ones can be reached from the top.
I think there is some misunderstanding. When you use a track pump (& most, if not all, hand pumps) with presta (& woods) valves nothing physically presses the valve open (unlike shraeder valves). Operating the pump until some air goes into the tube will equalise* the pressure in the tube & pump & the pressure gauge on the pump will indicate the same pressure as is inside the tube.MikeF wrote: ↑28 Oct 2021, 9:40am OK. I agree that works with Presta and Schrader because the "plunger" can press on the the valve, but in the case of Wood's valves there may not be a mechanical valve, eg rubber tubing or on the ones I've seen the valve is near the bottom and the "plunger" wouldn't reach it.
Maybe with some new ones the valve extends to near the top - I don't know.
Except the pumps I have, have a "plunger" that will press on both Schrader and Presta valves. It's operated by a lever.RickH wrote: ↑28 Oct 2021, 10:22pmI think there is some misunderstanding. When you use a track pump (& most, if not all, hand pumps) with presta (& woods) valves nothing physically presses the valve open (unlike shraeder valves). Operating the pump until some air goes into the tube will equalise* the pressure in the tube & pump & the pressure gauge on the pump will indicate the same pressure as is inside the tube.MikeF wrote: ↑28 Oct 2021, 9:40am OK. I agree that works with Presta and Schrader because the "plunger" can press on the the valve, but in the case of Wood's valves there may not be a mechanical valve, eg rubber tubing or on the ones I've seen the valve is near the bottom and the "plunger" wouldn't reach it.
Maybe with some new ones the valve extends to near the top - I don't know.
(* OK the pressure in the tube will have increased very slightly as you pump but the pressure will still be equal on both sides of the valve, unless you have a leaky pump.)
I would call that a pin. We have previously discovered during discussions that some pump heads have it but not all do.
You would need to operate the pump to obtain a reading for a Woods-valved tube, as there is nothing for the pin to depress. This small drawback is worth it for the great benefit of never having a failed valve core deflate your tube IMO... and I find that Woods-valved tubes hold pressure longer, but I think people suggested that may be because the remaining manufacturers are higher-end than the widespread cheap Schrader junk tubes, although I generally buy branded tubes of all valve types.I have a gauge on the track pump and when connected, the gauge will give a reading because air has been allowed to be realeased from the tube and reach it. If the valve hadn't been pressed the gauge would not give a reading. There isn't a need to operate the pump to obtain a reading.
I rarely use my pressure gauge - I just use my thumb as you describe - maybe a bit softer if its wet - bit harder dry.Wilhelmus wrote: ↑26 Oct 2021, 9:47am The old rule of thumb, when pumping up a bike tyre, was to stop two strokes of the pump before it bursts. Seriously, though, the great advantage of the old-fashioned cylindrical hand pump, for which mounting points were usually provided on the frame, is that it gives the user feedback, in the sense that it becomes harder and harder to get any more air in. This, combined with the finger and thumb test, usually proved adequate, even if you were Fausto Coppi or Tullio Campagnolo. With such a pump, it was virtually impossible to over-inflate a tyre.
What plunger? The air valve on a woods valve is at the base of it, and if it's rubber tubing it won't be opened by pressing a plunger. I've not checked if the valve on the more modern ones can be reached from the top.