silly question im sure, but is it normal to lose say 1psi ‘ish for a ride?

i normally never bother with pressures too much, i set my tubeless up about 30 psi rear/ 28 front or similar then tend to leave them until they seem pretty low or soft to touch..

today i set my advantage ust to 29 psi bang on, then checked again after the ride and it was reading 27.9 psi, so lost 1psi…

is this pretty normal?

i didnt puncture, plenty of sealant in (just today infact) so no obvious signs of leaking..

not really that concerned i know they go down over time, but didnt really think just one ride would cause a drop of 1psi

and also is it then pretty normal they drop pressure over time? ive always had this on 2 sets of wheels, but not sure if this is normal or not!

Hard to say but sounds about right – you’re talking about 3-ish percent loss per ride. They go down when sat in the garage but slowly, over weeks, but then it’s hard to compare air loss when stationary to that of riding.

With all track pumps I’ve seen there’s no way you could quantify this air loss with respect to measurement error. Are you using some sort of compressor that can measure to 0.1 of a psi?

hi garry – ahh cool, sounds pretty normal then from what you say…

i use a digital gauge, and to be honest when i put the gauge onto the presta valve it does hiss out some air, so probably lost some when doing that TBH too, so probably was actually less than 1psi….

any more thoughts on this, how regularly do you folks realise your tubeless tyres have lost alot of pressure?

When they start to feel soft

+1

I just apply the “squidge” test.

My motorcycle tubeless tyres lose pressure in a week – small, but still a loss. I check them weekly, probably pump them up once a fortnight. 2-5psi loss.

My tubed tyres (mountain bike / motorbike) all lose pressures.

Air molecules are small and basically slip through rubber.

(Incidentally Helium molecules are even smaller and slip through steel)

only some air molecules are small enough to slip through the rubber.

if you continue to top them up, eventually you will have only the large air molecules trapped in the tyre, then they will stay up for ever.

If you’re that worried about losing a few psi over a week, fill them with Nitrogen like F1 teams do. Less sensitive to temperature and leaks less.

[img]http://www.mlehworld.com/mleh3/images/smilies/smiley-laughing.gif[/img]

Testing the pressure releases air from the tyre. That could well account for most of your 1psi loss.

seems like its pretty normal to lose some pressure quite quickly then! i thought it was really, but since ive gone to flow rims from proper ust rims, i think they tend to go down a bit quicker than full on ust rims

its pretty clear i shouldnt just leave them for months then as i have been doing (plus all my sealant was gone too) as they clearly will lose a fair amount over that time!

packer – Member

Testing the pressure releases air from the tyre. That could well account for most of your 1psi loss.

this is also a possibility i must say, as careful as i tried to be when attaching the gauge…

I run about 30psi in both my tyres (UST rubber queens on stans flows with yellow strip) I always check the pressure before a ride and it’s always dropped to about 20psi.

I usually check mine most weeks, they lose about 5psi in that time.

wow steve so you really lose 10psi per ride? or is that every couple of days without riding when you go back to check?