Airbags on 37' Workhorse Chassis?

[BlauMax]

I have a 37' HR Admiral on a Workhorse Chassis.

As a note, DRIVER.. you made a comment that the Vin# could help you know what workhorse chassis you have.. Mine starts with 5B4MP67.. Does that help know what chassis I have?

Now the real question.. I saw someone else ask a similar question for a different chassis. I have an issue trying to back all of my RV's up my driveway. It's steep and the transition between the street (and the drop to the gutter) and the slope of my driveway have caused my 33' Hitchhiker to scrape (badly) unless I transitioned with some big planks. Didn't happen with my 29' Alpenlite because I "flipped" the axles.

Now, I have this new Admiral and I'm in the process of building some very heavy 2'x3' bridges that are about 5' high.. lots of weight and I'm hoping they will stand the weight of the RV.

As a thought, I was wondering if anyone has tried to use airbags between the rear axle and the frame to lift the back end... possibly enough to avoid using this excessive "bridge". There is a very tiny space.. maybe 4" filled with some sort of bellows looking device.. rubber or plastic.. about 3" in diameter.. doesn't seem like they could do anything.

If anyone has tried it:

What kind of airbags? How much can they lift the rig? The springs in the rear of this baby are two very heavy leaves on each side.

Thanks for any help.

["007"]

Bill you may not get the lift that you want with the overhang you have with your coach box from rear tires to back of coach bumper, to clear your driveway.
The AIR-LIFT bags are what I have used but for a different purpose on a Ford chassis.
You may only gain 3 to 4" but overhang is what may defeat that.
Have you thought of putting rollers mounted off chassis frame?

[BlauMax]

007.. sorry I don't know your name.

Thanks for the reply. If I could get 4".. that might be enough. I agree.. it's always the overhang.. Possibly, if I had purchased a diesel, the wheels would be much closer to the rear wheels.. (support the heavy engine).. but, alas.. I have what I have.


I bought a set of heavy duty rollers a few years ago for my Hitchhiker.. but I was afraid to use it because the chassis would flex too much. The fiver chassis' are much lighter duty, IMO, than a Workhorse chassis. I may be wrong. It might be worth a try to try the roller on the rear hitch. The only thing I'd be concerned about would be the extreme pressure on the concrete in my driveway. I don't know how many thousand pounds would be exerted down from the rear of the chassis.. all that weight would be concentrated on less than 1" square (I'd guess) of surface area of the rollers.

What do you think? Concrete is only about 3.5" thick.

["007"]

You will have to consider the pressure on chassis frame and if its a extended frame with welds not sure it would handle it.
I use rollers on a Ford frame but the clearance was not that great to clear.
A diesel might scrap the oil pan, not good.
Names Roger Moore- 007

[DriVer]

Originally Posted by GreatWhite

I have a 37' HR Admiral on a Workhorse Chassis.

As a note, DRIVER.. you made a comment that the Vin# could help you know what workhorse chassis you have.. Mine starts with 5B4MP67.. Does that help know what chassis I have?

GW, You have a W22 chassis.

Now the real question.. Now, I have this new Admiral and I'm in the process of building some very heavy 2'x3' bridges that are about 5' high.. lots of weight and I'm hoping they will stand the weight of the RV.

As a thought, I was wondering if anyone has tried to use airbags between the rear axle and the frame to lift the back end... possibly enough to avoid using this excessive "bridge". There is a very tiny space.. maybe 4" filled with some sort of bellows looking device.. rubber or plastic.. about 3" in diameter.. doesn't seem like they could do anything..

One of our newest sponsors is Air Lift. I would call them and find out if using their product will help you achieve your goals of raising the rear of the rig just enough to improve your departure angle. It might work!

About the air bags, they actually won't increase the GAWRR (weight rating rear) - I would not install them for that purpose. If they raise and lower the rear according to plan "that" would be a good thing.



Once you are on a level roadway, you want to make sure that you remove a little air from the bags to level front to back to reduce parasitic drag on the coach body

[BlauMax]

Thanks.. I guess a good recommendation would be to contact Workhorse and Air Lift. I can't see anything wrong with adding the bags to hyper extend the springs. But, I can see "007"s point about possible issues with the frame behind the springs. The WH chassis seems real strong.. so, might not be a problem.

Re GAWRR.. have no intention of trying to do that. Just the opposite.. I travel with empty grey/black tanks and only about 10gal of water. Fuel "economy" is an oxymoron..

Driver.. or any WH people. What is the purpose of the "plastic"?? bellows between the rear springs and the frame? They don't seem to be substantial enough to have any dampening or ?? value.

[JohnRR]

Originally Posted by GreatWhite

Driver.. or any WH people. What is the purpose of the "plastic"?? bellows between the rear springs and the frame? They don't seem to be substantial enough to have any dampening or ?? value.

Link to a recent thread.

[BlauMax]

Thanks John...

[pkmesser]

I put air bags on a P30 that had a lot of overhang. They made enough difference that I didn't drag bottom going in and out of stations, etc
.
The amount of lift that you get at the far back is greater than the actual lift at the axle. (visualize the rear axle as a pivot point.) If you want to estimate the possable lift, ratio the distance from the front axle to the low point at the backend, to the wheelbase. Multiply that number times the amount of anticipated lift the air bags will give you. (this ratio will be something like 1.6 on my 37 ft W22, so if the bags lift 2 inches, the lift at the hitch would be 3.2 inches)

Now, one caution, you will have to watch how much you extend the rear jacks for leveling, as you could overstretch the airbags. But, a side benefit would be a smoother ride.

[BlauMax]

Back again after a bit of research...

I checked with Air-Lift folks. Sounds like it may not provide enough lift. Also checked with Sumo.. definitely not enough change.

Finally checked with Firestone. Their P/N 2347 sounds like it will work. It will require drilling four holes per side. I'm not sure I'm up to it.. so will probably have it done... If I can get some agreement and help here.

I believe the Firestone guy said the bags would be at 10" normal position and they could go up to 15" height IF the shocks would allow that much travel. Does anyone know how much travel the stock shocks might go on that chassis? This would be a great help in making my decision. I don't have a beefy enough jack to find out.

Second... I have forgotten more math than I learned.. Geometry.. I would assume that the FRONT wheels would be a pivot point for this equation. What numbers would I have to provide my math helper to see how much the coach would rise at the rear "BUMPER"? Let's say it "will" go up 5" at the rear axle.. how do I find how much that will work out at the far rear of the coach? I know it will be more that 5".. but how much?

I'm not sure how to interpret the answer that PKM gave me in the above post. My brain is probably more dead than alive

Thanks for any help here......

[DriVer]

Originally Posted by GreatWhite

I believe the Firestone guy said the bags would be at 10" normal position and they could go up to 15" height IF the shocks would allow that much travel. Does anyone know how much travel the stock shocks might go on that chassis? This would be a great help in making my decision. I don't have a beefy enough jack to find out. Thanks for any help here......

G-Dubya! You can figure this out all by yourself.

Place a set of pads under your jacks and measure from your the lower part of the body panel to the driveway. (A) Next have someone push the up arrow and watch your rig go up. Immediately stop when the wheel just comes off the ground. (B) Measure the distance from the body panel to the ground. Subtract B from A = Suspension travel.

I'm not so sure if that will be 10 inches and definitely not 15"

[BlauMax]

Thanks DriVer.. Duh... I can do that.. I think..

Either I didn't make myself clear or (heaven forbid) you misunderstood.

Firestone said when the bags are installed in lowest position, they will be 10" tall.. when inflated to highest pressure.. they should be about 15".. which equates to a 5" lift at the rear axle.

I've drawn up a picture.. not sure if I need it.. but the measurements are

Front axle (A) to rear axle (B).... 242"
Front axle to lowest point at rear of coach (C) (bottom or hitch).... 392"
Height from driveway to bottom of hitch (D).... 23"
Height from driveway to bottom of hitch when extended???? "Assume" added height of 5" at frame above rear axle.

Do I need to provide height from driveway to bottom of frame at "B" before it's raised 5" ???

Thanks for input. I know we have math wizards here..

[pkmesser]

GreatWhite.
Your measurements are going to be almost identical to mine, a W22 chassis, and an overall MH length of 37'. So, the factor I showed in the example applies very closely to your situation, ie, 1.6 X actual lift at rear axle, is what you will have at the rear of the MH, probably the hitch is your drag point. If you get an actual lift of 5" at the axle, you would have 8" at the hitch. Now, I really question 5" of lift. That may be the uninflated height of the bag, but is it in contact at top and bottom in those circumstances. Also, with 5" of actual lift, you would be taking all the weight off the tires. I believe your rear axle weight is much greater than what the weight rating of those airbags is. So, do some further digging on this. In any case, they will probably help your situation.
Now, what I mentioned still applies, you need to either verify with the Firestones that it is not a concern, or, be careful when you lift with the rear stabilizing jacks, that you do not overstretch the airbags and damage them. (if you find it is not a concern with the Firestones, I am going to be interested in putting them on my unit for the ride improvement. Some other brands, it is a big issue.)

What Driver has given you to measure suspension travel will work, now, the numbers given to you by Firestone, if accurate, would allow for up to 5" of suspension travel, before stretching the bags. Now, I could do the measurement on mine, but because they are not exactly the same units, have different weights, etc, the numbers on that suspension travel will be close, but not the same.

BTW, the next time we go up 101, I will probably want to get a heads up on current road conditions on the 580 from the I-5 over to 101, and then on up to your area. (Probably next year now.)

[BlauMax]

Well, Driver.. looks like I can go up 8" before the wheels are close to lifting.. This, I think, is more than enough to "fix" my problem.

Now, I need to contact Firestone and start asking a few questions.