| air bag spring rate? [message #153484] |
Sun, 18 December 2011 19:57  |
jayrabe
Messages: 509
Registered: June 2009
Location: Portland, OR
Karma: 0
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Have noticed a strange thing. I have a slow leak somewhere in my air bag plumbing, so when I park, I close the Schrader valves so that the rear end doesn't end up squatting in a couple of days. But sometimes when I take off driving the next time, I forget to open them. When that happens, the ride is noticably harsher, hitting harder on bumps than if the Schraders are open. The only thing I can figure is that, with the Schrader's open, the effective air reservoir includes the bags plus the plumbing up to the electric control valves. It doesn't seem likely that a few feet of 1/4" tubing would make that much difference, but it sure seems to. Any comments? And, if that is really what's going on, could we get an even softer ride by using even larger tubing?
Thanks,
Jay Rabe
76 PB
Portland, OR
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| Re: air bag spring rate? [message #153488 is a reply to message #153484] |
Sun, 18 December 2011 20:18  |
Bob de Kruyff
Messages: 4260
Registered: January 2004
Location: Chandler, AZ
Karma: 1
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Senior Member |
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| jayrabe wrote on Sun, 18 December 2011 18:57 |
Have noticed a strange thing. I have a slow leak somewhere in my air bag plumbing, so when I park, I close the Schrader valves so that the rear end doesn't end up squatting in a couple of days. But sometimes when I take off driving the next time, I forget to open them. When that happens, the ride is noticably harsher, hitting harder on bumps than if the Schraders are open. The only thing I can figure is that, with the Schrader's open, the effective air reservoir includes the bags plus the plumbing up to the electric control valves. It doesn't seem likely that a few feet of 1/4" tubing would make that much difference, but it sure seems to. Any comments? And, if that is really what's going on, could we get an even softer ride by using even larger tubing?
Thanks,
Jay Rabe
76 PB
Portland, OR
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That is very unlikely. The rear impact harshness in a GMC is determined by the geometry not the spring rate. If you tend to shut it off when the rear is a bit high, the leading bogie will dramatically increase the harshness.
Bob de Kruyff
78 Eleganza
Chandler, AZ
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