s chassis air bag pressure

[Moxy]

as far as I can tell if your coach is riding to high the pressure in the bags is to hi as well, does it take more pressure to raise the coach, I have 01 Dynasty Chancellor with rear tag, manual says front at 11 and rear at 9, online sources seem to indicate that tag equiped should be 9 and 9, in which case my front is 2" to high which coincidentally is what it looks like so, question is will lowering the coach 2 inches change the firmness of the bags and soften the ride

Thanks

Moxy

[joeplazek]

Lowering the pressure in the front will definitely soften the ride. 2 inches is a lot of pressure. Not sure it will be noticeable but keep us posted.

[Barlow46]

Moxy,
Do a search on "ride height adjustment". You may need to call and see if Monaco still has the access to the specs for your particular coach. Have your VIN # ready when you call. The ride height is adjustable from under the coach but just lowering your pressure is not what controls the height. There is an adjustment that let's you change the ride height. The search can give you much more information.

Here is a link with some information. http://www.precisionframe.com/rvdeta...tProcedure.pdf

Here is an even better link from this forum with a chart showing ride heights. http://www.irv2.com/forums/f115/2001...ht-138127.html

If the chart is correct, you should be 9 1/2 front and 11 rear. Double check your manual and see if you posted the measurements in reverse. (11 front and 9 rear)

[Mr_D]

I always thought the pressure going in was pretty constant but the volume in the air suspension bags varied. The ride height valves just let air in or out, but the pressure was set by the compressor cut out.

[joeplazek]

Well,,,, lets put it this way,,, you visualize setting a weight on a ballon,,, to raise the weight you would need to put more air in the ballon and hence more pressure would be needed to lift the weight.

joe

[moisheh]

Somewher in the air circuit there must be a regulator between the air bags and the air tank. I doubt they use the compressor full pressure as there is a cut in and cut out pressure. The ride height valves control the AMOUNT of air that is in the bags. The tag axle usually has a regulator that is adjustable. But changing that setting can transfer ort ake weight off the front axle.

[Moxy]

Originally Posted by joeplazek

Well,,,, lets put it this way,,, you visualize setting a weight on a ballon,,, to raise the weight you would need to put more air in the ballon and hence more pressure would be needed to lift the weight.

joe

Thats kinda my question, I have concluded that you do infact have to increase the pressure to increase the volume so in doing so the bag becomes stiffer and less compliant so does this change change the ride? geometry aside i hope it does cause the front seams to bang hard and I cant go any less on the front tire pressure.

[Moxy]

Originally Posted by moisheh

Somewher in the air circuit there must be a regulator between the air bags and the air tank. I doubt they use the compressor full pressure as there is a cut in and cut out pressure. The ride height valves control the AMOUNT of air that is in the bags. The tag axle usually has a regulator that is adjustable. But changing that setting can transfer ort ake weight off the front axle.

As there is a valve controling tha amount of air it would not relate directly to the air pressure, the air goes in the bag until it reaches a certain height and the ride height valve closes, if it needs to increase the high the valve would again open and the line pressure would have to overcome the pressure in the bag to lift the coach any higher, hense the higher than needed pressure if the coach is too high, thats my take on it so far.

[Moxy]

Originally Posted by Mr_D

I always thought the pressure going in was pretty constant but the volume in the air suspension bags varied. The ride height valves just let air in or out, but the pressure was set by the compressor cut out.

The max presure is set by cut out but that pressure is not necessarily in the bags they only accept the volume needed to lift the coach to a certain level, if the pressure is high the coach lifts faster but when it reaxches its set high the valve closes.

[Moxy]

Originally Posted by Barlow46

Moxy,
Do a search on "ride height adjustment". You may need to call and see if Monaco still has the access to the specs for your particular coach. Have your VIN # ready when you call. The ride height is adjustable from under the coach but just lowering your pressure is not what controls the height. There is an adjustment that let's you change the ride height. The search can give you much more information.

Here is a link with some information. http://www.precisionframe.com/rvdeta...tProcedure.pdf

Here is an even better link from this forum with a chart showing ride heights. http://www.irv2.com/forums/f115/2001...ht-138127.html

If the chart is correct, you should be 9 1/2 front and 11 rear. Double check your manual and see if you posted the measurements in reverse. (11 front and 9 rear)

you are right i had them reversed

[Tony Lee]

If you have automatic ride height valves fitted as is the case with most large motorhomes, and if it is set to the original specifications and is working correctly, then trying to alter suspension characteristics by varying ride height is not going to be productive.
Whatever pressure is required to support the weight is what it has to be and altering the ride height by adjusting the valve control rod is just going to alter the height and the pressure inside the bag remains essentially the same.

What does happen if you change the ride height is you alter the possible travel of the suspension and that isn't very likely to improve anything unless it was wrong in the first place.

BTW A balloon analogy doesn't come close to describing a system with automatic ride height system, but does apply to some smaller coaches with manually controlled airbag pressures.

[moisheh]

You have a tag axle coach that should ride like a Limo ( well sort of). I would start with the basics: Are the shocks original? If they have been replaced what did you install? Have you weighed the entire coach : EACH wheel position if possible? Then you can adjust each axle to the proper tire pressure. What make and model of tires are on the coach? I hope they are not original. Those questions need to be addressed before playing with ride height.

[Moxy]

Originally Posted by Tony Lee

If you have automatic ride height valves fitted as is the case with most large motorhomes, and if it is set to the original specifications and is working correctly, then trying to alter suspension characteristics by varying ride height is not going to be productive.
Whatever pressure is required to support the weight is what it has to be and altering the ride height by adjusting the valve control rod is just going to alter the height and the pressure inside the bag remains essentially the same.

What does happen if you change the ride height is you alter the possible travel of the suspension and that isn't very likely to improve anything unless it was wrong in the first place.

BTW A balloon analogy doesn't come close to describing a system with automatic ride height system, but does apply to some smaller coaches with manually controlled airbag pressures.

I have valves that are mechnically controlled based on the position of the axle in relation to the valve arm there is no relation to the pressure in the bag, I am under the assumption that pressure dictates the height you can pump more air in unless you increase the pressure, maybe using a under inflated tire analogy is is closer than the balloon comparison, so more pressure, higher ride height higher psi in the bags means stiffer ride. I dont know of any automatic ride height systems, I have an automatic levelling system but the ride height is still controlled manually by the ride height valves and as far as I know i have the same as the signatures and exec's.

So if I were to inflate the bags to their max capacity they would have no flex or travel and the coach would ride like a buck board, conversly if i were to reduce the pressure to a minimum that would not allow the suspension to bottom out but as soft as possible, the ride would be smoother no?

[joeplazek]

Originally Posted by Moxy

I have valves that are mechnically controlled based on the position of the axle in relation to the valve arm there is no relation to the pressure in the bag, I am under the assumption that pressure dictates the height you can pump more air in unless you increase the pressure, maybe using a under inflated tire analogy is is closer than the balloon comparison, so more pressure, higher ride height higher psi in the bags means stiffer ride. I dont know of any automatic ride height systems, I have an automatic levelling system but the ride height is still controlled manually by the ride height valves and as far as I know i have the same as the signatures and exec's.

So if I were to inflate the bags to their max capacity they would have no flex or travel and the coach would ride like a buck board, conversly if i were to reduce the pressure to a minimum that would not allow the suspension to bottom out but as soft as possible, the ride would be smoother no?

Sorry guys but the ballon analogy was just a basic to describe how the air pressure/air volume worked since there seemed to be some confusion. You can use a tire, an air shock, an inflatable matress, a ballon, or anything you desire. The bottom line is the more air pressure you pump in the higher and stiffer the bag will become (before burst of course). The less air you put in the lower and softer the bag will become (just prior to bottoming of course). I am well aware that these systems are way more complicated than that as there are many valves and sensors in the system to accomplish overall height and ride.

Ride height should be set to the perimeters the engineers designed the suspension to work in. Don't ever think that it could not be wrong from the factory. It could be way off. Check with the chassis manufacturer and set the height to the recommended height. If it was off then you have found a problem that would effect ride and handling.

joe