|   Does Altitude effect RockShox SID XC? | EugeneinNYC
Aug 3, 2003 3:50 PM | | I am taking my sealevel NRS to the Canadian rockies. Do I need to be concerned about the change in altitude affecting my RockShox SID XC? |
| altitude changes will affect almost any fork, especially air... | zedro
Aug 3, 2003 6:08 PM | | sprung forks. Not to worry though, its just a matter of recalibrating your air pressure to what you normally ride (ie. higher altitudes will raise your air pressure). |
| altitude changes will affect almost any fork, especially air... | EugeneinNYC
Aug 3, 2003 7:20 PM | | Should I depressurize the shocks before flying to Alberta? |
| not necessary.... | zedro
Aug 3, 2003 7:53 PM | | the overall affect will not be huge, its more of a fine tuning issue. People dont explode as they get off the plane in Alberta, so neither will your fork :). |
| not necessary.... | EugeneinNYC
Aug 4, 2003 3:44 AM | | that certianly puts it in perspective! :~> thx |
| Correct... | Lucky
Aug 4, 2003 5:41 AM | | And I love the analogy!
The difference between sea level atmosphere and absolute vacuum is only 14.7 psi. The difference between sea level and 10,000 ft is far less than that, and is probably less than the accuracy of most shock pumps, or at least within the user's ability to put in the same pressure each time with said pump.
I've never had trouble with my air shocks going from sea level to mountain passes. The motor, on the other hand, suffers mightily.
Kathy ;^) |
| Not sure. | Axe
Aug 4, 2003 6:20 AM | | External pressure will affect it only if it is the external pressure that acts as negative spring, that determines the equilibrium position of the piston (unloaded position). If it is a coil (making the external air pressure less important), or an air negative spring - then there should be no effect, right?
Temperature, I would imaging, will have a much bigger effect in such a case. |
| Guage pressure | Dougal
Aug 4, 2003 3:08 PM | | All pressure guages read pressure relative to atmospheric. If the atmospheric pressure drops by 2psi then you have 2psi more guage pressure in your shock (or fork) and it'll behave that way.
Dougal.co.nz |
| Guage pressure | Axe
Aug 4, 2003 10:56 PM | | Not at all. Many gauges measure against sealed volume. Imaging - thin membrane (or moving piston), measured pressure on one side, sealed volume of gas on the other side. Piston will move until pressure is equal on both sides - assuming that the measured volume is much larger then the sealed its position will be proportional to the pressure. If it is vacuum outside - it has NO EFFECT.
No, lets say left side of the chamber, separated by a moving piston is you positive chamber. Right hand side - negative. Total volume is sealed. If you drop outside pressure to vacuum - it has no effect.
If you move the piston - pressure changes on both sides of the piston and the resulting force will return it to neutral position. You can easily integrate this equation to get the response curve - good freshmen year homework for non-engineering majors. :)
If one side is open to the outside pressure, movement changes pressure only on one side. Equilibrium position and resulting response curve will be affected of course by this outside pressure.
Dougal, Dougal...you need to brush up your physics. ;-)
|
| Nope. | Dougal
Aug 5, 2003 1:07 AM | | Do you really have a PhD in physics? You're coming out with some extremely dumb comments. Try pulling apart a pressure guage sometime and it's perfectly clear. They all read relative to the atmospheric pressure.
A sealed volume doesn't work, for the simple reason that it'll give non zero reading when the outlet is open to atmosphere. Useful as a barometer or altimeter but useless as a pressure guage. Especially useless as a safety device or shock guage as the readings then aren't the true pressure differential.
You're currently offering an interesting mix of stupidity, snobbery and inexperience to these forums. I don't know what your PhD thesis was but it can't have been anything remotely practical or mechanical.
Dougal.co.nz |
| Bullshit. | Axe
Aug 5, 2003 2:30 AM | | >Do you really have a PhD in physics?
Yes I do. From Stanford Univ., CA. Obviously - you do not.. ;-)
>You're coming out with some extremely dumb comments. Try pulling apart a pressure guage sometime and it's perfectly clear. They all read relative to the atmospheric pressure.
No, they all do not. Some do. Many simple ones do indeed. The point of my example was to illustrate the physical system with am overall sealed volume for the simplified dual chamber fork example- but we know you have comprehension problems. You did not get the point.
>A sealed volume doesn't work, for the simple reason that it'll give non zero reading when the outlet is open to atmosphere
What an arrogant idiot you are. If the sealed volume has certain amount of gas, when the other end is open it will settle in a position where the sealed gas has the same pressure as the atmosphere. That would be your reading, dummy, of the external pressure. Non zero, obviously. It works just fine.
>Useful as a barometer or altimeter but useless as a pressure guage.
ROFL. What do you think altimeter is? It measures PRESSURE.
Did you actually understand my example with the fork? Nope you did not.
>You're currently offering an interesting mix of stupidity, snobbery and inexperience to these forums
I though you are just a bit rusty on technical terms and ignorant. But you are also an asshole. Sorry I misjudged you.
|
| And my penis is bigger. | Axe
Aug 5, 2003 4:58 AM | | It is humongous. You should be jealous and follow up each of my post with explanations of correct measurement procedures. |
| |
