Front tyre pressure dropping

I try to keep my tyres at the pressures in the manual (33/36), checking them every two weeks or so. Almost without fail my front tyre pressure has dropped to 30 over that period of time, and I'm just wondering why this is.

I see these as the options, but feel free to add a fourth!

1. This is normal, they always drop slightly.
2. Not normal - I have some sort of slow puncture
3. It's the pump

To expand on 3: I go to the pump at the forecourt of tesco/sainsbury's - I use this as the gauge and the pump, but have heard this is not the most accurate way of doing it. If this is the case do you have any recommendations on either pump/gauge or ideally pump+gauge (all in one).

Thanks!!

~redders.

[yorkie_chris]

Not normal.

Forecourt gauges are not good though, any footpump will do, verify it against someone else's gauge and if it's near enough then be right. Whatever, it will probably be consistent for you, which is all you need, not absolute accuracy.

I am losing pressure slowly atm. I think its the valve seal on the rim. Best thing is to take it to a tyre shop and ask for reseat and new valve, then go from there. Shouldnt be too expensive, £10-£15...

Cheers - I'll get a footpump then and keep an eye.

Is the valve stem leaking? Put your thumb over it and feel for any build in air pressure. Schrader valves can be tightened if leaking.

[dyzio]

Spray some soapy water/screenwash over the valve and where it joins the rim to see it it leaks, and get a foot pump.

[timwilky]

On the brothers Mille, he lost pressure whenever he rode it, never when stored. In the end he took out the valve stem, pityfull spring on it, looked like it belonged on a push bike. scrounged a new stem from the local tyre fitter the spring was twice the size. Pressure loss problem cured.

Thanks for the help guys, will let you know when this is resolved + how

[Spanner Man]

Good morning all.


A loss of 1.5 psi per week is pretty normal. Often it's due to the tyre fitter not cleaning the rim of the wheel when fitting a new tyre. As said, check your valve.

As tyres & wheels are made to tolerances. Sometimes a particular tyre/wheel combination will lose a little air from the bead of the tyre. Whereas the next tyre of the same make & model on the same rim wont.

As I frequently have to remind my customers, check your tyre pressures weekly, or every 200 miles or so.


Cheers.

Instead of buying a foot pump, why not just get a small digital (but accurate) pressure gauge and keep it under your seat. You can then use the forecourt pumps but check it with your own indicator to make sure its the right pressure. I do this with my low quality halfords inflator, it says 40ish on the needle but is only really about 36psi!