Hi Bob,

Sorry, I didn't notice your post... I see Private Messages, but wasn't watching for profile comments.

If the air suspension system changes height while moving, that would change the amount of load transfer by the WD system: lowering the tow vehicle will increase load transfer, and vice versa. A large amount of ride height change would be undesirable, but with any luck this can be turned off... and this is a feature available only with four-wheel air suspension, not with rear-only systems. A system with only auxiliary air springs, in addition to steel springs (coil or leaf) is unlikely to have automatic height changes, only maintenance of a constant ride height.

With one of these height-changing systems, it would be reasonable to set the WD for moderate load transfer at normal ride height, knowing that it will increase in the lowered state, but that won't fix a more fundamental problem: changing the tow vehicle height will change the tongue height of the trailer. Lowering the tongue by a couple of inches with a single axle trailer is okay, but with a tandem-axle trailer it is a problem - with Torflex axles it will certainly decrease stability. I think it would be advisable to turn off any ride height changes, with or without WD.

Most people seem to depend on raising the trailer's tongue with the tongue jack to make it easier to put the WD bars in place (with chains or with the fixed brackets)... but most systems are designed with a lever to engage the bars so this shouldn't be necessary. Even with air suspension the tongue jack trick will still work anyway, although if the air suspension system reduces air pressure enough, the hitch would be pulling down on the trailer with a lot of force. The obvious fix is to shut off the tow vehicle's engine while hooking up the WD - the air suspension control will not be active when the vehicle is off.

Brian, I am no expert on trailer hitches or towing and I know I don't know the answers to many questions. Your comment that air suspension systems work fine with WDH has be going in circles. The air suspension system on some cars adjusts to keep the car level and the height of the vehicle from the road automatically changes with speed. The air system can also change depending on driving mode selected.


I can understand how the bars might be able to be installed if they use chain to make-up the bar to the trailer but the bars that ride on a preset ledge on the trailer tongue might be too difficult to bend to get onto the ledge. The car will stay level while trying to bend the bar. I don't think that the air suspension can be turned off on these cars. Maybe by pulling a fuse or something but I'm not sure about that.


Also, the car can change height for different road conditions and speed. I think this change is less than a couple inches but it could change the driving dynamics while driving. In reality maybe this change in driving dynamics is nothing more than is encountered when going over bumps or dips in the road with regular suspension.


The dynamics would be different on air assist systems that augment spring suspension. I don't go in circles when thinking about using WDH with these types of systems.