Pumping up air shocks. Not working, help :-) !!

[seadragon]

Is there some trick to pumping up shocks on a bike? I have borrowed a suspension pump from a guy at work. I screwed on the fitting, pumped up to 14 psi and when I unscrew the pump you hear a whooshing noise as expected I am told, but ALL the air seems to be running out, so no difference in all in pressure, ie, it is still flat as a pancake

Am I doing something stupidly wrong, surely it cant be that hard? I have tried the same thing with both front and rear shocks on my new bike, with no difference.

Many thanks

[jfdi]

The air cylinder in the shocks is quite small hence very easy to let it all out whilst removing the pump. The pump i have has the ability to screw out the centre first thus releasing the centre of the valve so when you unscrew the outside part no air escapes.

[barker22]

14 psi, is that right? The rockshox on my bike need around 60psi and I am only around 10stone.

Does the suspension actually work?
Is there resistance there already and you just want to fine tune it? Or does the suspension feel like there is no air in there at all?

[seadragon]

My bike is a folding one with front and rear susp (Dahon Jetstream EX). The directions say it needs to be no less than 4 and no more than 20 but I cant seem to hold any pressure :-)

When I sit on the bike it sags ride to the ground, like a car thats been slammed. It does rise again but cant put any weight on the bike at all. Wish now it had come with spring suspension or elastometer

Edited by seadragon on Friday 5th July 16:26

[seadragon]

jfdi said:

The air cylinder in the shocks is quite small hence very easy to let it all out whilst removing the pump. The pump i have has the ability to screw out the centre first thus releasing the centre of the valve so when you unscrew the outside part no air escapes.

Thanks for that so maybe I need a different pump or one of those air loss preventing adapters I have seen on Wiggle.

[Fluffsri]

Is the valve a shraeder valve, like a car valve. If so is the core still in the middle of the valve, seems strange all the air rushes out straight away.

[rhinochopig]

You do get a hsssshhh sound when you remove the pump; it's the noise of the air within the pump - not the shock - escaping. However, if the shock is not pressurising at all it sounds like either the valve or an internal seal is shot and it's service time.

[seadragon]

rhinochopig said:

You do get a hsssshhh sound when you remove the pump; it's the noise of the air within the pump - not the shock - escaping. However, if the shock is not pressurising at all it sounds like either the valve or an internal seal is shot and it's service time.

Thanks I thought it might be something to do with the shock, not the pump. well the bike is brand new, albeit an old model, so maybe no use has rendered inoperable.

off to the bike shop i think, thanks for the help.

[M400 NBL]

No less than 4 and no more than 20? Isn't that bar? ie x 14.5 to convert to psi!

20 psi wouldn't hold up a small child. I doubt your cylinder is the problem. Pump it up to at least 150 psi and it may be fine.

[seadragon]

ok thanks, will give it a try

The range is 4 - 20 bar, my mind went blank when I was writing the original post.