screw type lift like on a handicapped van?

[blazer2007]

I was wondering if this type of setup would work or if anyone has tried them,just thinking.

[andrewmp6]

You mean a linear actuator?And what would you use this for ?

[Overdriven]

I don't know what all handicap vans use but a quick google of "kneeling systems" points to something other than a screw type mechanism. Most seem to use an actuator with an arm an chain or just a small winch to pull the rear suspension up, compressing it and lowering the vehicle.

Anyway, I assume you mean using a screw type mechanism to adjust the upper spring mounting point on the chassis though. NASCAR vehicles have this but it's manual and yes others have built motorized versions. Screw type mechanisms like this that are motorized are called linear actuators which are notoriously unreliable. Burnt out motors, stripped gears in the gearbox, etc and that's before you factor in them being exposed to the elements under a vehicle. Then there's packaging and I doubt there's an off the shelf solution for this kind of application.

If you want to be low but able to raise up for obstacles air bags are the way to go. Off the shelf air bag kits handle way better than they used to. If you're looking for a setup tuned for handling just talk to the manufacturer to spec out bags for your ride height, some nice adjustable shocks and sway bar options. Compared to air bags, you might be able to get slightly better handling with a linear actuator adjusting the upper mount of the spring but you'd need to be hardcore to go through the effort required for minimal gains.

Btw there are some systems used by vehicle manufacturers for raising vehicles to clear obstacles. Lamborghini has one and it uses a hydraulic pump to increase the pressure in the coilover shocks (temporarily) which makes the coilover extend, raising the vehicle. Easier packaging, less complexity/cost in the chassis, less worries and maintenance due to exposure to the elements and maintenance are some of the reasons to use this kind of system instead of linear actuators.

[blazer2007]

I just thought it might work on a static lowered truck for a little lowering or raising.It was just a thought after I was looking at one of these vans.

[andrewmp6]

Air ride works easier.