Foretravel Owners' Forum

Foretravel Motorhome Forums => Foretravel Tech Talk => Topic started by: U295 Owner on April 03, 2019, 08:20:39 pm

Title: Air Bag Pressure
Post by: U295 Owner on April 03, 2019, 08:20:39 pm
I was having some work done on my coach when I overheard the service manager tell another customer that he had lowered the airbag pressure on his coach to give him a softer, less jarring ride.  Have any of you heard of this?  Or had it done to your coach?


Larry
Title: Re: Air Bag Pressure
Post by: John44 on April 03, 2019, 08:24:28 pm
Not sure about the coach he was talking about but if you lower the pressure the coach will sit lower.
Title: Re: Air Bag Pressure
Post by: red tractor on April 03, 2019, 08:29:34 pm
What year coach do you e?
Title: Re: Air Bag Pressure
Post by: wolfe10 on April 03, 2019, 10:58:32 pm
Not possible to lower air bag pressure on any air suspension coach I know of without lowering RIDE HEIGHT.  A dangerous solution-- hard on suspension and drive line!

Would love to know what coach and who in the world recommended this!
Title: Re: Air Bag Pressure
Post by: jcus on April 04, 2019, 03:51:58 pm
Maybe he was talking about tag axle air bag pressure, some coaches have an adjustable regulator, so you can load or unload the weight the tag bears.
Title: Re: Air Bag Pressure
Post by: U295 Owner on April 04, 2019, 04:01:09 pm
Didn't ask the service manager because it would be somewhat embarrassing to admit I was eavesdropping on his phone conversation.
Title: Re: Air Bag Pressure
Post by: wolfe10 on April 04, 2019, 04:25:09 pm
Maybe he was talking about tag axle air bag pressure, some coaches have an adjustable regulator, so you can load or unload the weight the tag bears.

Could be, but changing tag axle pressure would have very little effect on ride quality and if lowered, would materially overload the drive axle and under-load the steer axle.
Title: Re: Air Bag Pressure
Post by: John44 on April 04, 2019, 04:35:48 pm
We have Firestone air bags on my Excursion front leaf springs,lowering pressure does lower the truck,could be what he heard.
Title: Re: Air Bag Pressure
Post by: wolfe10 on April 04, 2019, 04:37:56 pm
We have Firestone air bags on my Excursion front leaf springs,lowering pressure does lower the truck,could be what he heard.

Ya, AIR-OVER ________ is very different than air suspension!
Title: Re: Air Bag Pressure
Post by: jcus on April 04, 2019, 04:39:12 pm
Could be, but changing tag axle pressure would have very little effect on ride quality and if lowered, would materially overload the drive axle and under-load the steer axle.
But isn't it possible that if tag pressure was too high, weight would be transferred to the front axle, perhaps overloading it, and front bag pressures would increase causing a rough ride, and if too high, would also unload drive axle and perhaps overload tag axle causing a problem there too?
Title: Re: Air Bag Pressure
Post by: wolfe10 on April 04, 2019, 04:45:00 pm
But isn't it possible that if tag pressure was too high, weight would be transferred to the front axle, perhaps overloading it, and front bag pressures would increase causing a rough ride, and if too high, would also unload drive axle and perhaps overload tag axle causing a problem there too?
Absolutely.

Incorrect tag PSI/load can either under or over load the other axles.

Ideal is to have the same percent of GAWR on each axle.

It really takes scales to properly set this-- been there, done that!
Title: Re: Air Bag Pressure
Post by: Shady Lady on April 04, 2019, 04:47:34 pm
Surely the air pressure in the air bags is directly related to the weight supported by the air bags and the only way to adjust the ride height is by adjusting the ride height valves.
                                                                                                Cheers, Mike.