Tyre Pressure Gauge Guts

ianyonok · Apr 3, 2020

Ever wondered what was inside a tyre gauge? No, me neither.
But mine stopped working, so thought I'd have a look inside.
I bought this gauge at Halfords when I was a kid, for bicycles.

Ah, rather clever. The top of the brass piston has a screw holding a leather sealing washer which had worn out.
I cut a small piece of leather off the missus' handbag.... an old one... Then punched out a washer with i.d. tight on the piston stem and o.d. slightly larger than the tube bore.
After fitting the washer, it needed squashing with oil a bit and poking into the tube. But after some working in and out, it loosened up and after re-assembly, the gauge looks like it will last another 50 years...

canthai · Apr 3, 2020

I have one in all my vehicles. Most the type you show, but also a couple of dial types.
All read different - some close, but different.
Surprisingly - the dial type always reads higher than the piston type - only a couple of lbs, but noticable.
My HD does not seem to mind the difference, or the CB650 or the CRF. So I go with whatever gauge is on the bike.
Thanks for the pic - never had one apart.

DavidFL · Apr 4, 2020

What is the age of that gauge then?
It has a long life.

ianyonok · Apr 5, 2020

I have had this gauge about 50 years. It worked fine, for the first 49 of them.

scotty007 · Apr 11, 2020

Remember using pumps like this as a kid! Taking them apart to see if they could be made to pump the bicycle tyres up quicker! Sure is a testament to the manufacturing of the day there is no way a modern pump would last even 10 years now.

ianyonok · Apr 11, 2020

Hi Scotty,
Well, maybe it depends what modern pump you buy.
I just bought a pump for a 1940 BSA M20 (fits on lugs on the underside of the petrol tank) and it is surprisingly well made. All steel body and tube with aluminium end piece.

It weighs about half a kg and has strong pressure. 56 pounds from Draganfly Motorcycles in UK.

Oddvar · Apr 12, 2020

This is a 1200 bath bicycle pump capable of 90 pounds. Been glued several times and is about 3 years old. Comes with me on dirt bikes. The only nice thing about it is weight and size.

ianyonok · Apr 12, 2020

That looks great, easy tuck in a bag.