I was wondering if air shocks perform differently in the Alps compared to the UK..due to the pressure in the shock and the relative atmospheric pressure, at altitude.

Will it?

slightly. What pressure do you run it at ? Going from sea level to the top of Everest will give about a 3% change at 150psi…

150psi in the piggy back bit of a coil shock.

Guess the relative increase of pressure in the chamber when it goes to the Alps won't amount to much then.

No it won't. Your shock is a rigid container so the pressure, and by implication the performance, is not affected by the drop in external air pressure. The only effect that it could possibly have would be on it's ability to contain the pressure but this won't be an issue as you will be nowhere near the pressure limit of the cylinder.

Nitrogen in shocks is another story mind.

Nitrogen in shocks is another story mind.

I'm lucky then since 79% of the air in my shock is nitrogen. 😀

Nitrogen in shocks is another story mind.

No it's not.

"Your shock is a rigid container so the pressure, and by implication the performance, is not affected by the drop in external air pressure."

Yes it is.

The answer is yes, but but you will not notice any difference.

Container is "rigid" but it will have a slightly changing volume in relation to the relative pressure difference between the two walls – in and outside the sealed unit. But it is designed to run at such high volumes that the increase in size of the chamber is completely minimal. Otherwise the chamber would flex bigger as your pumping it up and this would lower pressure causing you to pump more and more and then bang.
It is a bit like you holding your breath and going underwater – you are a sealed unit – but not rigid, you will decrease in volume – air in lungs under higher pressure. Chamber just designed to minimise this "desire" to change volumes to equalise pressure.

I would lump it in with.
a) Will a hot day make my tyres feel different?
b) Will Helium in my tyres make my wheels have less mass?
c) Will Helium stay in my tyres?
d) Will I ride more grrrr with facial hair on my rigid SS.

I'd be more concerned about the effect of the decrease in gravitational force at altitude due to spherical divergence, but then of course this could be counteracted by localised gravitational increases due to the density of the underlying strata…………

Yes, but not enough to make a difference. Your more likely to notice you cant breathe well before your shock runs into problems.

LOL at bigdonx. 😆