Thread: Adding Airbags
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Old 12-03-2019, 09:54 PM   #28
Theunz
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Join Date: Mar 2016
Location: Catoosa
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M.O.C. #18384
Quote:
Originally Posted by Twopetes View Post
I will jump in and add some engineering on the air bag smoothing out the ride. Springs have constant support (unless you have variable travel springs - usually coil type springs) so the truck depresses the spring based on the weight, then the truck rebounds with the total strength of the spring until the spring is at the end of itís travel. The air bag increases the pressure inside the bag as the truck pushes down effectively increasing the support the bag is providing and decreases as the truck rebounds, meaning the lifting pressure / push from the air bag will decrease as the pressure decreases, which will give you a lessening upward push, making the rebounding motion easier or as most would say, smoother. And as you may have guessed, I have air bags which I air up to about 35-40 psi to level up the rig.
I am certainly no engineer or suspension expert, but your idea that the air bags will rebound slower just doesn't seem to register in my mind. Air bags, like leaf springs are not progressive but linear, in essence if it takes 100lbs to compress one inch then it takes 200lbs to compress two inches. The rebound is therefore linear as well. The air bag will rebound just as fast as the steel spring, even faster if you have enough air in it to lift the truck higher then it was before you added air. So if you have a (the following numbers are arbitrary and I am using just for simplicity) 100 lb per inch leaf spring and add air to your bags the spring rate of the air bag is now in excess of 100 lbs, say 125lbs. Now while it will take an extra 25 lbs of force to compress your suspension one inch it will also have 25 more lbs of inertia to unload it. This is why we have shocks, and why quality shocks make a difference. Shocks have separate valves for rebound and compression which can slow down either the compression or rebound dictated by the manufactors design parimiters. Shocks on off road and racing vechicles usually have external adjustments so as to tailor the suspension for the desired effect. Now air ride suspension, bags without steel springs is a whole different conversation.
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