07 E450 Class C rear air bags better handling while towing

What is the "loaded for travel" weight of your unit? I see it has a GVWR of 14050 lbs. How close to that number are you when you travel? If you're within a hundred pounds of that max, or possiby over it, your problem is the chassis is overloaded and there's not much you can do about it. It's subject to the laws of physics. You can make the suspension more firm or robust, but that just moves the stress of the weight to the tires and frame. Find a way to lighten it up, and see if that helps. Otherwise, get used to it.

Although, for some reason it seems like cutaway chassis seem to have finicky front ends and steering.
See alot of cutaways with bad tire wear. Including a relatively new E350 box van my buddy has. Front wheels are massively positive cambered. Like the front end is going to lift off.
Rear springs look like a frown. And he don't have all that much weight in it. Maybe 4000lbs (unless he loads up on parts for a job) and the heavy stuff is in front of the rear axle.

yukon01 wrote:
We just took a 2000 mile trip and I have uneven tire wear on the passenger side front on the inner tread, cupping. I have been in the automotive business for 45 years. So I asked two of my technicians and of course they disagreed on what the issue is. One believes it is an alignment issue and the other feels it is front end float and air bags on the rear would help the situation prior to new tires and a alignment.

It's alignment, camber specifically, and neg camber, or a combo of camber and toe.
If you were heavy in back, the front tires would possibly get a little positive camber from the front suspension being stretched a bit (not likely, but not neg camber).

We don't know how heavy the back of your RV is. If it's truly at max, and taking enough weight off the front to affect the steering, then, again, bags aren't really going to solve that. They'll help, but only a little, as raising the back of the rig a couple inches at most isn't going to change the geometry enough to put alot of the lost weight back up front.

It helps, especially those who are not very familiar with auto mechanics, to separate the issues. And in your case, you have 3 things:
1. Flat towing (adds no significant weight to the back of the rv) shouldn't affect how the rv steers appreciably, so leave that one alone.
2. Rear axle weight. Figure out your weights and if it is actually maxxed out and/or taking significant weight off the front.
3. Alignment, pretty much mutually exclusive of the other 2 things, and your front end isn't aligned properly. Sounds like it could be out on caster camber and toe.

I read through the initial post and see the OP inspected his stabilizer bar bushings.

There are many products available that address handling. I lean most toward replacing the under-rated stock stabilizer bars versus adding rear air bags. But that is surely a personal decision.

Our old 1983/84 Toyota chassis motorhome HERE that we had for many years, had very serious handling problems. Heavy duty stabilizer bars were not available so the other practical option was to add rear air bags. They did the job well for vehicle control, but in order to be effective, they required a good amount of air which increased the harshness of the ride. I feel heavy duty stabilizer bars achieve the same without making for a more rough ride.

Tire wear is the clue here IMO. Class Cs tend to be light on their front feet for steering, but should not have un-even tire wear in front if aligned. Perhaps something wrong with the "front end" ?

Ford E-Series chassis always require a LOT MORE caster angle than the factory specs.

Regardless of what your inspection showed, I would replace all 4 ball joints. Put the cupped tires on the rear.

You will need to play with pressure settings in both tires and airbags when you get them. We bought 1 year old winnebago aspect (class B+/C) and when we left to come home it had terrible handling (about 400+ miles worth). Tire shop would not put air in rear airbags and could not check inflate rear inners! Yes this was a major tire store! Anyhow got home and check and rear airbags were basically empty, tires were set to high psi reading except for inners. I have had airbags on several vehicles and have had to play with them all. Found that the front on rv need to run 55-60 and rears 65-75, airbags 55-60. Running OEM shocks (have new monroes but havent been able to install to high heat temps over summer). Anyhow as noted above the 80psi max is way too high for most for a good ride/handling. There was a magazine road test on the winnebago some years back and they were harsh on the handling but I cannot locate a copy of it anywhere.

we run a light load with max weight around 14K, do not run full water tank (about 1/3d) and keep black/grey drained. So it will be up to you to experiment and Yes I do recommend airbags if none installed.

posted another item but it has not been posted to the board. Happens often it seems. Anyhow if you do install airbags go for adding a built in compressor so you dont have to crawl around to add air and can also do on the fly to further help with your efforts. Stabilizer bars may help but really are not the cure all IMO.

First question, what is the tire pressure on the front tires? If it is 80psi, the max on the tire sidewall for the maximum load capacity, it is way to much. Look at the Ford sticker on the inside of the drivers door jamb and it will say the pressure for the front will be 65psi, the amount needed for the maximum load if the axle is loaded to the maximum gross axle rating. When my front pressure was set to 80, the vehicle was almost impossible to handle, when I dropped it down to 65, it became a pleasure to drive.
Note all tire pressures are cold ambient pressure, whether it be 65 in 0F or 65 in 90F ,

Second, sway when flat towing. I had a similar problem when I started flat towing the CRV. The problem was a sloppy hitch receiver on the MH. It allowed a side to side movement in the tow bar. An 1/8” at the MH would almost be 2” at the front wheels of the toad. I use a hitch quiet?sp , to make the connection solid. In my case, that reduced/eliminated the sway.

Ken

I have 2012 E-350 24 Nexus C. When I started towing my 6 X 10' {8' tall} cargo trailer I added Air Lift5,000# air bags. Without them the rear end would sag 1.5" with a the trailer loaded to 2,600#. With the air bags inflated to just 50# the sag vanished and the top of the ball is exactly 16" high per the trailer manufacturers instructions. When not towing I keep 25# in them and this too improves the ride and handling.

I did replace the original shocks at 33K miles with heavy duty Bilsteins and could not be more pleased with the results. Get your coach weighed as you normally travel and take those weights to your tire manufacturers load inflation tables and air your tires to those numbers.

Works for me.

:C

Get an aligment and use correct tire pressure before throwing any more parts at it.