LXI SUSPENSION ISSUE

[cmillsap]

(10-20-2014 21:02)davidbrady Wrote:  Thanks for the diagram Chuck. Funny thing though - I don't see a pressure regulator to set the tag axle pressure, do you? In fact, the whole system is different from my fixed tag. Notice how the left tag axle air springs are tied to the left drive air springs and likewise for the right. On my LXi the tag air bags are tied together like the steer axle. If I'm reading the diagram correctly, it looks like tag pressure isn't adjustable on this schematic and air delivery is regulated by the height control valves on each side. This is how SpongeBob is set up.

Regarding the extra weight calculations for when the bike is on board, I made a huge assumption, and that assumption is that the tag air is plumbed the same as my LXi; i.e., a pressure regulator sets the tag air spring pressure. If that's the case, then regardless of load applied, the spring pressure is determined by the regulator which means the tag load has to stay constant with or without the bike. But, all that goes out the window with this new air diagram.

In short, the 1500 lb bike shifts the CG from 15.33' to 16' behind the steer axle. If the tag load stays constant at 13K lb (but this is no longer true), then the remaining weight is divided by the drive and steer as shown: the drive gains 2800 lbs and the steer loses 1300 lb such that the net difference is the weight of the bike, or 1500 lb.

Do you see a pressure regulator for the tag air springs in your schematic?

BTW, my #1 calcs aren't Al's true weights. Those numbers are a guess at what a typical 43' slide equipped LXi would come in at per axle. (I had to start somewhere)!

David,

I believe all steerable tag equipped WLs had the tag pressure pre set at the factory and there was only a connector block located center of the tag axle and hidden under the foam insulation. When I increased the air pressure on my steerable tag, I had to replace that connector block with a regulator valve. I would make a guess that all steerable tag equipped buses were set at around 55 psi depending on what the weight distribution dictated. Although I doubt that BB weighed the individual axles on each new bus. They probably assumed that around 55 psi would distribute the weight load pretty close.

Sorry, I just assumed you had the actual weight of Al's bus. Al should weigh his bus so we can see how 100psi onthe tag affects his axle weights.