Originally Posted by retiredChemist
With a computer, they're a progressive rate not linear rate spring. The equations to do it are in most adaptive suspension research papers. The maths gets a bit complex without a computer.
The kneeling valve just takes some pipework and a valve and a brake switch and a lock it out unless stopped mechanism.
For going up instead of down, the leveling valve needs to be fooled. Most air bag systems sit at about 2/3travel, all you're doing is moving that up to 3/3 travel. Using stock bits nothing should get damaged as it's within a designed failure parameter, broken leveling valve.
Most skoolie rear air bag systems are about as simple as it gets as far as maintaining a level.. they are a purelyt mechanical valve and lever arm so its real easy to make it electronic and / or fool it..
im not sure what kind of transit busses you are looking at but the gilligs they run in my city are fully bagged but have an absolutely terrible ride quality qith it seems like a lot of flex.. I feel like my 25 year old short school bus with only rear air bags has a better ride quality..
plus the floor lines in some of them are wierd with the rear portion of the floor raised compared to the rest of the bus.. ..
there was one parked early this AM and I looked under and around it.. I dont see how you get much ground clearance on it even if the kneeling valve were pumped to the max.. these busses are made to be lower for ADA access... the rear appears to have a bit more clearance but theres a lot of equipment stuffed back there..
if you go the route of a travel trailer and a pickup.. I seriously would budget for a 1 ton rather than 3/4 ton... I know people will tell you all day long their 3/4 ton will pull their 5th wheel but reality is its not as nearly nice of ride.. of course if ground cleaerance is an issue you arent going to get much of it with the 5th wheels ive seen..
for ground clearance a school bus is going to bne the way to go I believe..
I still think a coach builder can put a shell together... 4 leg seat frames are quite heavy and easily modified and bolted through the floor into the body ribs for anything you need to secure... I love them...