Attn you M.E.'s

What is the ambient pressure in absolute at 5k feet? Consult your Molier diagram, your steam table, your Carnot Engine or your Magic 8 Ball. I was curious since I did not vent off my fork legs in Moab (that had been vented off at sea level). I want a good reason why my hands were getting beat to death in Moab.

For some reason I noticed the fork thing more when we got back down to sea level,you mean your supposed to bleed your forks?

I think the 4000ft at Moab is irrelevant unless the cargo compartment of that plane your bike took a ride on was pressurized the pressure drop from sea level to 30,000 feet might be significant enough for u to notice.

Yes Howard, you are supposed to bleed 'em. It's the screw right beside the dampening screw on top of the fork. If you don't bleed them it makes the fork harsh.


According to the Pratt and Whitney Aeronautical Vestpocket Handbook: Sea Level absolute atmospheric pressure is 14.70 psia. At 4000 ft it is 12.69 psia.

In simple terms: forks sealed up at Sea Level and taken to 4000 ft would be like forks pressurized at about 2 psi gage at 4000 ft.

Eric in WA

Thanks Eric for the info.

I still need to drain my forks completely and put the min level oil in. Just putzing around my yard today, my forks feel too stiff off the top. It doesn't help that my right wrist is still trashed!

I'f bleed'in the forks will make me a faster rider I'll DO IT, thanks :)

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