Dave Solberg is a leading expert in the RV industry and author of the “RV Handbook” as well as the Managing Editor of the RV Repair Club. Today he discusses an RV’s suspension system.
What would be the first step in suspension improvement for a 2016 Thor A.C.E. F-53 Ford chassis? —Bernie
The first thing I would start with is getting the rig weighed by individual wheel position, if possible. The RV Safety & Education Foundation has weighing teams that attend rallies and have weighing opportunities. You can find their schedule here.
Individual wheel position is best as it will tell you if there is more weight on one side or wheel position than the others, which is not uncommon on bigger rigs. If you cannot find an RVSEF location near you, then the next best thing to do is weigh it at a CAT Scale, which you can find here.
Put the front wheels on the first pad and the back wheels on the second and you will at least get individual axle weights.
Look for Gross Vehicle Weight Rating
The first weight you are looking for is Gross Vehicle Weight Rating (GVWR). That is the maximum weight your rig can weigh with all fluids, accessories, and people in the rig. If you are over GVWR, then you run the risk of tire failure, brake and axle issues, as well as stopping issues. Just because you have huge storage compartments all along the basement of your rig doesn’t mean you can fill them up.
After you get the individual axle weights, divide it by two, or four in the back, and get the weight that is on each tire. Then go to rvsafety.com, and then go to the tire manufacturer’s recommended tire pressure chart. Recommended pressure can only be obtained by getting the weight and verifying by the chart. The psi on the side of the tire is MAXIMUM psi at MAXIMUM GVWR.
Next, get an alignment, as the alignment that may have been done at the RV manufacturer was on an empty rig, plus it could get extremely out of alignment during delivery.
First-hand suspension issue
Our resident Pet Vet writer Karel Carnohan, DVM, purchased a used Newmar and had a horrible driving experience recently. She found that she had tire pressure issues and a bent suspension component. Getting an alignment would identify this situation. Also, during the alignment and inspection, the technician needs to check the shocks as they can be bent, weak, or even need to be upgraded.
Once all these components are verified, you can look at additional suspension enhancements such as SumoSprings or Roadmaster Reflex Stabilizer.
There are several other products available. However, Roadmaster is one that most of the RV dealers and manufacturers recommend. On the high end of the price spectrum is LiquidSpring®, which is the Tesla of suspension systems. (I remember when we used to say Cadillac, but that doesn’t seem high-end enough these days.) They have a suspension system specifically designed for the Ford F-53 chassis. I had the opportunity to test drive one at the 2021 Hershey, PA, show and it was amazing.
Check out the product here.
Read more from Dave here.
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Take a road trip. Drive south down the Oregon coast. Then go east on Hiway 199 to Grant’s Pass and see the suspension specialists at Henderson’s Line-up. (make an appt first, they are popular and very effective…..search the internet). Oh, if you like Pizza, Abby’s Legendary Pizza, well it’s legendary!!!!! and it’s across the street from HL.
My F53 chassis rode AWFUL as well. Several things helped. First was to replace the 16 ply tires that were on the front. Way overkill. Replaced them with Bridgestone 12 ply tires, which carry the 6000# the front of my M.H. weighs with ease. Totally different ride. Next was a new pair of shocks. Recommend Bilstein or Monroe RV shocks. Lastly, and this will sound crazy, I removed the sway bar. It was WAY oversize, and the rig did not need it with the leaf springs. Did not make a bit of difference in the sway, but the ride? . . . . Wow! So much better. Hope this helps. Ford will learn to build chassis someday.
I believe you are living dangerously without a sway bar. The sway bar has no effect on smooth ride, it only prevents the body from swaying side to side. I had the right side sway bar bracket fall apart on my F53 chassis and couldn’t drive faster than 52 mph on FL I 75 due to the side wind. Going to a lesser ply rated tire may ride softer but you’ve seriously compromised your safety. Simply lowering the pressure from max to a pressure needed to carry the load would be safer.
I had a Ford F-53 chassis motorhome and the ride was less than desirable. Over the years I added a road master steering stabilizer and larger Road Master torsion bar in the rear. This really helped the handling of the unit but the ride was still harsh. I then removed the over travel bumpers and installed air bags, compressor and upgraded shocks. What a difference that made, the ride was much smoother and the MH was not pushed to the side when a tractor trailer passed me. It was not as good as the diesel pusher I now own but not far off! I was able to do all of this work myself with the help of a friend that is a truck mechanic, so the cost was only the parts.
My rig drove as rough brand new as it does fully loaded today. Admittedly it’s for safety reasons but in my case it made no difference. I hold out hope that someday Ford will include some meaningful upgrades to their F 53’s.
Ford will only do that when RV manufacturers are willing to pay for it, and as long as people keep buying motorhomes with the chassis that’s under them RV manufacturers are not going to make Ford improve them. The problem is people keep buying their motorhomes on glitz instead of content. I’d bet most RV executives don’t even know the problems with the Ford chassis.
Maybe Roger can provide some insight on this as I have worked with The RV Safety and Education Foundation for over 25 years researching and educating on tire safety including proper inflation. Here is what the Michelin Inflation Chart States:
MICHELIN INFLATION CHARTS FOR RV USAGE
For RV use only, Michelin displays the loads per axle end in the load and inflation tables, as we recommend weighing each axle end separately and using the heaviest end weight to determine the axle’s cold inflation tire pressure. For control of your RV, it is critical the tire pressures be the same across an axle, while NEVER exceeding the maximum pressure limit stamped on the wheels. To select the proper load and inflation table, locate your tire size in the following pages, then match your tire’s sidewall markings to the table with the same sidewall markings. If your tire’s sidewall markings do not match any table listed, please contact your Michelin dealer for the applicable load and inflation table.
If you mismatch the pressures on steer axle you’ll definitely have handling problems. The tire that’s lower pressure will cause that tire to pull the steering wheel in that direction. Have you ever driven with a low tire, you can feel it even with power steering.
Nice write-up Dave. Only issue is the suggestion to “go to the tire manufacturer’s recommended tire pressure chart.” Those charts are not recommended pressures. If you read them closely you will see that they give you the maximum load at each pressure level. You will not find the word “recommended” on the chart, just “maximum.” Usually there is a statement in there that says that tires should be inflated to the RV manufacturer’s recommended pressure, which is almost always the maximum load pressure on the sidewall. For example, My Goodyear Endurance tires only need to be inflated to 25 psi to carry the actual load of my trailer but 80 psi to carry the maximum load the tires were manufactured to carry. You’d have to be a fool to only inflate to 25 psi. My guess is that low of inflation would flex the sidewalls, heating up the tire, and leading to premature failure, though that’s reall a question for Roger Marble.
My TT specifies 65 PSI and that’s the max pressure on the sidewall, I don’t think manufacturers put much larger capacity tires than they have to to give that much leeway.
Ford should upgrade their suspension to handle the difference between a cargo truck and RV. Manufacturers of RVs should demand this of Ford but since manufacturers don’t use their own products they never understand that the F-53 chassis is for hauling heavy freight and not a motorhome.