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**robnolimit** · 11-28-2010, 02:32 AM

Stich, you are correct. Mant have tried to make a perfect spring, which would have an increasing spring rate as it compresses. Variable rate springs have not been so successfull due to the pre-load at ride hieght. With air, as you compress it at ride hieght, the effective spring rate rises, and thats a good thing. As you unload it, it becomes softer. Years ago we tried to add small tanks plummed into the bags, to act as a resivour and add to the volume of air, and reduce the change in pressure as it is compressed. It works great on a spring rate gauge, until you bring "time" into the equation. Real time testing showed that even with 1" line, by the time the pressure equalized, the bump or turn was over. Start tuning by choosing the correct bag, one that will be at 80 - 100 lbs at RH, with the bag in it's posted sweet spot. Minor corrections can be made with shim spacers, usually 1/4" alumn. and air pressure.

11-28-2010, 02:32 AM	#16
robnolimit Senior Member Join Date: Jul 2010 Location: Dandridge, Tn. USA Posts: 2,226	Re: how well do bags handle? Stich, you are correct. Mant have tried to make a perfect spring, which would have an increasing spring rate as it compresses. Variable rate springs have not been so successfull due to the pre-load at ride hieght. With air, as you compress it at ride hieght, the effective spring rate rises, and thats a good thing. As you unload it, it becomes softer. Years ago we tried to add small tanks plummed into the bags, to act as a resivour and add to the volume of air, and reduce the change in pressure as it is compressed. It works great on a spring rate gauge, until you bring "time" into the equation. Real time testing showed that even with 1" line, by the time the pressure equalized, the bump or turn was over. Start tuning by choosing the correct bag, one that will be at 80 - 100 lbs at RH, with the bag in it's posted sweet spot. Minor corrections can be made with shim spacers, usually 1/4" alumn. and air pressure.