How much pressure in rear shock?

[blsnelling]

I just acquired a 250R ATC rear shock. It seems to function correctly. However, I checked the gas pressure and it's only about 40-45 lbs. Is there any reason I can't go down to Tire Discounters and fill it up? They use Nitrogen. If so, how much pressure should be in it?

[Colby@C&DRacing]

You lost most of the nitrogen charge just trying to test it. Never try to test the nitrogen pressure in a shock.

[blsnelling]

It's true that when you check the pressure on a small volume system, that you loose a lot of pressure with a small loss. However, when you check it and it only has 45 psi, you know it's low. I just purchased this 20 year old shock and wanted to see if it had any pressure at all. I took it to Tire Discounters today and shot it with 140-150 psi of Nitrogen. Custom Axis says 175-200 psi in their rebuild manual. 140 is a lot better than 45. I'm sure I'll be getting it rebuilt soon but need it to ride this weekend.