I bought a new, unused mini-pump from Ebay, here:
From the enlarged views, you can see that the pump works with both Presta and Schrader valves.
For two kid's bikes, I can only get the pump to fit one valve out of four. For the other three, I seem to be screwing forever, with no mating.
Here's some info.
- I use the Schrader setting. So the valve end of the flexible extension is screwed fully in.
- The pump fits my car (UK)
- All caps fit easily on all bikes.
- A cap from my car fits all valves on both bikes.
- All the caps from the bikes fit my car.
- All caps, including the car are countersunk. So roughly 4 pitches of thread are missing. This makes the cap self-centering, so it's easier to start the thread, even if the attitude is slightly incorrect. I think If the threads on the flexible extension had been countersunk, I might have succeeded.
- The flexible extension is not as flexible as they were 50 years ago. Those extensions could easily form an "S" shape. There's not much space for my fingers (but more space than with a chuck). The reduced flexibility of the current extension means that it's difficult to angle the knurled end such that the axis of the knurling is inline with the axis of the valve. So the angle is offset by about 2 or 3 degrees, which is enough to prevent the threads from mating. I suppose a stronger guy with leather-tipped fingers might be able to do it.
I would be grateful for any advice on how to fit the pump to the valve.
Edit: All the above info about car caps and bike caps was to prove that I have a schrader valve rather than a presta valve.
But I've just seen photos of these two valves here, and there's absolutely no resemblance (as many people probably know):
So, based on these photos, my valves are definitely schrader.