Tire Pressure (again}

[buswarrior]

Ride height control valves

Get rid of the word "level" and a bunch of this goes away.

Happy coaching!
Buswarrior

[TomC]

Spring suspension, two valve air ride, torsilastic can be different weight on the front. But a single leveling valve operating both sides of the front axle will net exactly the same weight on both sides, no matter what the rear axle is doing since they are equalizing side to side constantly. Good Luck, TomC

[richard5933]

Spring suspension, two valve air ride, torsilastic can be different weight on the front. But a single leveling valve operating both sides of the front axle will net exactly the same weight on both sides, no matter what the rear axle is doing since they are equalizing side to side constantly. Good Luck, TomC

But don't the rear height valves control both the front and rear for each side? So if I put a 1000 generator on the right side, the rear height valves are going to put more air pressure in both right corners, front and rear. The suspension keeps the body parallel to the axles, but there is still more weight on the right side of the bus.

It was explained to me that the front valve only controls the nose up/nose down, and that the rear valves only control side-to-side.

Or am I missing something here?

[chessie4905]

Someone need to go to the scales that has manual air suspension control and settle this once and for all.

[luvrbus]

All I know for sure is my DL3 is 217# heavier on the drivers side aired up to the ride height I never checked when not aired up,could be thicker brake shoes on that side what do you think

[dtcerrato]

"But a single leveling valve operating both sides of the front axle will net exactly the same weight on both sides, no matter what the rear axle is doing since they are equalizing side to side constantly. Good Luck, TomC

What Tom said is the way it is. The tripod leveling system on the Monocoupe GMs prevented the "box" from being tweaked. There's no one that I have more respect for than the civilian engineers of post WW era because previously they or someone close to them were probably military hardware engineers. While our bus height is maintained by the original height control valves the box is in static mode - no creeks or noise of any kind. The second the tripod leveling is defeated by manual means and the tripod becomes a quad, the "box" starts talking. The mechanical pivoting axle is exactly what the front one height control valve is doing for the tripod air height control on air spring suspension.

[dtcerrato]

If a scale is showing 217# difference side by side on a front axle with one height control valve - that weight difference is happening below the bottom mounts of all the air springs...

[richard5933]

If a scale is showing 217# difference side by side on a front axle with one height control valve - that weight difference is happening below the bottom mounts of all the air springs...

Are you talking about unsprung weight?

I still don't understand why there wouldn't be a different amount of weight pushing down on each side. The air bags on the heavier side will have more air pressure in them, resulting in the body of the bus staying parallel to the axles, but those air bags are still carrying more weight. Therefore the tire is carrying more weight.

If only the rear axle adjusted side-to-side to accommodate a weight imbalance, it would seem that the body of the bus would have to be torqued to keep both ends parallel to their axles on flat ground.

[luvrbus]

My DL3 has the tripod system like as on any bus,the only thing different in both sides is the steering sector on the drivers side 

[dtcerrato]

The fact that there are two height control valves on the rear axle means that each side (2 bags + 2 bags) has independent psi to each pair of bags. The fact that the one height control valve on the front axle means that the front whole air suspension system (all four front air bags) have exactly the same psi in each & every bag so the downward pressure on both sides of the axle are exactly the same - ie: from the bottom support of all four air bags upward. If there is a difference of side by side front axle weight it has to be occuring below the bottom air bag supports...

"The air bags on the heavier side will have more air pressure in them, resulting in the body of the bus staying parallel to the axles, but those air bags are still carrying more weight. Therefore the tire is carrying more weight."

Richard what you stated above in quotes is EXACTLY what is happening on the REAR axle ONLY.

[luvrbus]

If you put a 2x6 across 2 blocks and stand in the middle the weight would be the same on both blocks right,so what would happen if you moved 2 ft in either direction would it change or not  ?

[Dave5Cs]

Yes because the longer cantilever would add more weight,

[Dave5Cs]

You guys keep saying this statement,

"the body of the bus staying parallel to the axles"

Think about that, that does not always happen. You can call it Leveling or ride height but in reality the bus adjusts to ride height or level while moving and unless the road is perfectly level this can not happen....

Unless the body reaches down and pick up the axles, which it does not do so many times there is more measured distance between the body and the axle or less but not also and very rarely parallel.

[richard5933]

You guys keep saying this statement,

"the body of the bus staying parallel to the axles"

Think about that, that does not always happen. You can call it Leveling or ride height but in reality the bus adjusts to ride height or level while moving and unless the road is perfectly level this can not happen....

Unless the body reaches down and pick up the axles, which it does not do so many times there is more measured distance between the body and the axle or less but not also and very rarely parallel.

The way you set the ride height valves is by measuring the gap between the bumper on the body and the axle. The goal is to get it to maintain the same gap on both side. Accomplish that and the body of the bus is parallel to the axle.

Bring the bus to a bus stop and load up with passengers. They all decide to site on one side. The bus wants to go down on that side, causing the ride height valve to put more air in that side to bring it back to the present point. Result is that the body is again level to the axles.

...Richard what you stated above in quotes is EXACTLY what is happening on the REAR axle ONLY.

But it's impossible to disconnect the rear of the bus body from the front. If what you're saying is accurate, then if you add 1,000 pounds to the right front right corner of the bus, the right rear tire will be carrying a bigger load and then left rear, and both of the front will equally share their portion of the new load?

It would seem that this would put a twisting force on the body which would do eventual damage if it was always in such a state.

[luvrbus]

Air bags replaced leaf springs years ago for cost and comfort that why they are called air springs it is still the same principal when it comes to weight distribution that did not change