Bicycle pumps

[Harry Bloomfield]

I picked up a little bike pump, to keep on the mobility scooter, in case of emergencies. It's quite a short, hand pump, with a built-in pressure gauge, the business end, uses a small lever, to clamp onto the valve.

Thumb over the overlet and extend the pump, it springs straight back, due to suction - there is no obvious way for air to enter the barrel, which I don't understand. I've not tried blowing tyres up, but how can it blow tyres up, if the cylinder, in front of the piston, cannot refill with air?

The bike pumps I've seen before, alway had a greased leather cup for a piston - on the return stroke, air would pass into the cylinder, around the cup. This one just has a couple of O rings around the piston. No obvious way for air to bypass the O rings, on the return stroke.

 

[Wayners]

Hand pump I guess you have. Like the old fashioned type although it has more modern features.

The end is reversible. Check it's correct as the inside bits swap about so it fits both Presta and Schrader valves.
If assembled wrong it won't work. Could be that?

 

[accelerator]

Try pumping a tyre up with it to see if it works. If it doesn't, post back here.

 

[motorbiking]

you haven't bought a shock pump by mistake?

 

[Harry Bloomfield]

The end is reversible. Check it's correct as the inside bits swap about so it fits both Presta and Schrader valves.
If assembled wrong it won't work. Could be that?

Nope, the end connection is part of the pump casting/moulding. It only fits Schrader valves.

 

[Deleted member 317777]

Buy one of those little usb pumps from eBay etc. I used it use one for expansion vessels. It was decent for the size.

I’ve moved to a Milwaukee 12v one now. That’s a proper bit of kit

 

[Wayners]

You sure?
Many pumps including car pumps and bike pumps have reversible ends.

You unscrew the bit that fits over valve.

I didn't know myself until recently.

 

[motorbiking]

does it look like this:

 

[Harry Bloomfield]

does it look like th, is:

No just like a short pump, with the valve end, built into the pump, and the gauge likewise a part of the pump.

Block the valve outlet with a thumb, and it creates a vacuum, if you try to expand it - and it springs back to the closed position.

 

[Stivino]

Like this?

 

[Mottie]

I have some very short pumps that I carry in the pouches of my bikes - no more than about 6” in length. To use them, you withdraw the pump handle then unscrew the handle to make it work.

 

[Deleted member 317777]

I have some very short pumps that I carry in the pouches of my bikes - no more than about 6” in length. To use them, you withdraw the pump handle then unscrew the handle to make it work.

I also have one of those I’ve used at work. Tbf, it’s not bad.

 

[Harry Bloomfield]

Like this?

Not like it - that very same one.

 

[Wayners]

@Harry Bloomfield

Check the valves are correctly assembled.

 

[Scally-Ho]

When I bought my Cat 3 mobility scooter I also bought (on-line) a rechargeable pistol-grip tyre pump. Its easy to use and I select 26PSI before attaching and then away she goes until the set pressure has been reached .