If you’ve been around RV’s for awhile you have probably heard of the term “sway,” even if you don’t pull a trailer. It’s a common term in the RV industry and it means a side-to-side movement. Sway is normally associated with a travel trailer being pulled by a tow vehicle, but it can take on a whole new meaning for motorhome owners too.
We currently own a 35’ Class A motorhome on a Ford chassis. The first time I drove this motorhome on the Interstate I experienced sway in a motorhome, when a semi-truck passed us. Rather than calling it sway, when a truck passes you from the rear, I refer to it as the “push-pull effect.” As the truck is passing the first thing you feel is the air pressure from the truck pushing against the side of the motorhome. Then as the truck starts to go past the motorhome it pulls you back in. This sensation makes the motorhome feel top heavy.
Other terms used for sway, as it pertains to motorhomes, are “body roll” and “pitch.” You will experience these different types of sway whenever pressure is exerted against one side of the motorhome. It can be caused by a gust of wind, or a shift in weight while cornering. The effects of sway on a motorhome are increased because of the height and mass of the motorhome. Regardless of what term you use for it, over time it takes its toll on the driver.
The solution to sway is in the suspension. Chassis manufacturers are aware of this problem, and in an effort to reduce sway they use what is referred to as a sway bar. The sway bar is the link between the suspension system and the vehicles frame. The sway bar uses the weight of the rear axle as a brace against the chassis, so any pressure exerted against either side of the motorhome is countered by the sway bar. The problem with this, in many cases, is the stock sway bar installed by the manufacturer is not strong enough to absorb or counter the effects of sway or pressure exerted against the sides of the motorhome.
Now that we know what the problem is, what can we do to fix it? Once again I will mention that I am no way affiliated with this product, but the solution I found was called the RSS sway bar by Roadmaster Inc. RSS sway bars have thicker diameters than stock manufacturer sway bars. They’re made of 4140 “chromoly” steel which is stronger and more durable than the spring steel used in most stock sway bar applications. The RSS sway bar works by reducing the body roll and balancing the weight transfer during cornering.
Another problem related to stock sway bars are the bushings they use. Sway bars pivot as pressure is constantly being countered by the bar. Most stock sway bars use rubber bushings at these pivot points. Rubber bushings harden and wear over time, causing the motorhome to roll or lean even more, from the same amount of pressure exerted against the side of the motorhome. RSS sway bars use polyurethane bushings. Polyurethane won’t wear like rubber, and it holds up much better at these pivot points.
After installing the RSS the real test was to see how the motorhome handles on the road. I drove the motorhome slightly over 7,000 miles without the RSS sway bar, and after driving it 750 miles with the RSS sway bar all I can say is the difference is like night and day. I wish I had it on the motorhome the first 7,000 miles. The motorhome is more stable on the road, it handles and corners better and the body roll or sway was drastically reduced. If you experience sway when driving your motorhome, and are tired of white knuckle driving experiences the RSS sway bar could be the solution to your problems too.
Happy Camping,
Mark J. Polk
Marcel
I have a 40ft Holiday ramble it is really bar driving in the wind would road master sway bar help
Gary Mots
I agree with Ron and Bob, My motor home a 34′ Pace Arrow was leaning a little to the right side, probably not noticeable to anyone except me, I took it in to a spring shop, thats all they do is springs for motor homes and trucks, the guy told me before he would replace the rear springs, the big problem was the front springs and air bags. I had him manufacturer new springs specially for my motor home all the way around, plus install new air bags.
What a difference there was in the ride. It wasn’t cheap, but it was will worth the money spent.
Like said before, I was thinking about installing the bell crank and steering damper, etc. he told me to save my money and try this first, glad I listened to him.
Gary Mots
I agree with Ron and Bob, My motor home a 34′ Pace Arrow was leaning a little to the right side, probably not noticeable to anyone except me, I took it in to a spring shop, thats all they do is springs for motor homes and trucks, the guy told me before he would replace the rear springs, the big problem was the front springs and air bags. I had him manufacturer new springs especially for my motor home all the way around, plus install new air bags.
What a difference there was in the ride. It wasn’t cheap, but it was will worth the money spent.
Like said before, I was thinking about installing the bell crank and steering damper, etc. he told me to save my money and try this forst, glad I lestened to him.
bob
I agree with the last post, I do have air bags on my coach, and an alignment and the best of all the Koni fsr shocks. made a world of difference to the ride. holds the road and no sway. It is a workHorse but my last MH was a p32 and did the same thing. Shocks/alingment and good tires make a big difference bob
Ron Curry
Frankly, it doesn’t have to be a big expense to get a good riding coach.
I own a Fleetwood Flair (for sale) with a P-32 chassis that once handled terrible and now handles like a nice SUV. I’ll share what I did to it.
First, I did NOT go out and buy every gadget on the market that various companies sell to supposedly help this. I called upon my experience with 4 wheel and 2 wheel vehicle suspension (both on and off-road) and went back to basics and the basics are front-end alignment, tires, shocks, and springs. All have to be in good condition and up to the task. Unfortunately, front-ends or these coaches (I’ve owned 4) are often misaligned from the factory on coaches which are built on mass produced chassis’ because the only front-end alignment done was when the chassis was built and before the coach was mounted on it and therefore caster and toe-in are changed once the heavy coach is mounted on the chassis. Also, the shocks and springs were never up to the task even when new on many coaches, and old tires do not handle as well as new tires. So here’s what I did:
1. I got a front-end alignment from a shop with the right equipment and expertise. That would be a major truck tire shop – not your local passenger car tire shop. If the shop even sells passenger car tires it’s probably not the best place to get an alignment (or even buy motorhome tires for that matter). Just as important, I instructed them to ensure it had plenty of caster and toe-in dialed in – to the limits but within spec.
2. I got Koni FSD shocks. This made a HUGE difference in the handling of the coach in the wind, when passing semi’s, cornering, and when driving over bumps of any type. Made this coach handle more like a passenger SUV rather than a motorhome. I’ve tried Bilsteins, Monroe, and others. They didn’t make nearly the difference the Koni FSDs do.
3. I got new tires. The tires made only a minor difference but they made a difference. I got Goodyear G670s and I’m sold on them for this application. My new coach came with brand new Michelins and they seem ok but I’d rather have the Goodyears if I had my druthers. Also, VERY important to know the weight on each axle on your coach and make sure you buy tires with at least a 20% wieght carrying margin. Soft tires with marginal weight handling (for your RV’s weight) will ride nice but the handling is compromised and you increase your risk substantially of blow-outs.
4. I made sure the airbags and all the tires have the proper pressure. Airing the front airbags to 100PSI makes a HUGE difference on most of these P chassis coaches. The front springs are just not stiff enough. The other alternative is to replace the coil springs with the proper size (something the coach manufacturer should have done when the sold it) from someone like SuperSteer but I’m convinced that it’s not necessary if you inflate the air bags properly. Tires run at too low of pressure will handle very squirrelly and are DANGEROUS. Get some air in them. Start with the coach manufacturers dataplate (not what the tires say – that’s max pressure at max weight) until you find the proper inflation pressure from the tire manufacturers weight/inflation tables available from their websites.
5. I had my airbags re-plumbed so that each airbag has a separate filler valve. Actually I did this years ago when I got my first coach with airbags. If yours are plumbed together, separating them will make a big difference. It’s the equivalent of adding a big swaybar and the same concept as the SuperSteer Motion Control Units for air suspension diesel pushers (except a lot cheaper).
These things made my P32 based coach handle great to the point that I found no reason to invest in all kinds of wild (and expensive) braces, humongous sway bars, etc. You’ve got to get the basics right before you can decide if you need any expensive add-ons. If I was dealing with a really long coach with a lot of overhang I MIGHT consider a rear axle brace but only AFTER I did all the above inexpensive stuff first.
Lastly, if you ask for advice on the forums you are going to get a lot of it. Some of it is excellent. Some of it is not good. It’s hard to sort out. Best advice I can offer is to consider the source. It’s easy to throw money at problems and if you ask commercial vendors like SuperSteer they will want to sell you one of their products. I must say I know the SuperSteer people to be mostly knowledgable (I did have one guy there tell me that “stiff shocks “push” the tires harder on to the ground” though!) and have some good advice but you are going to spend a bunch of bucks which may not be necessary. On the other hand some advice from users may cost your or be wrong also because most people have a tendency to believe what they have (or did) was good and to want to defend it.
My advice is start with the basics first, get the above items right first then spend big bucks on sway bars and the like later and then only if basics don’t solve the problems.
BTW, I have no connection to any vendors. I’m just a guy who has owned 4 motorhomes over the last 20 years and has built race cars, motorcycles, and aircraft as a hobby.
Good luck!
Mac McClellan
Good article.
We have an older RV, a ’95 Southwind on a Chevy P-32 chassis. We’ve added several suspension and steering improvements. They all seem to help some. Ours used to drive like a boat in ocean swells. It still drives like a boat — but now it’s like a better boat on a smooth lake.
We’ve added:
* HD Front Sway Bar
* Poly bushings on rear Sway Bar
* Henderson’s Super Coils up front
* Henderson’s bell cranks
* Koni and Bilstine shocks.
* Billstine stearing damper
Mac
jack francis
The pic seems to show a factory installed “sway bar” and and after-market “trac bar”. Thanks for your help with this. A lot of us need more information on this subject!
jack francis
What is the difference between a “sway bar” and a “trac bar”?
John Ratliff
Who sells the sway bars? Does it matter if the motor home is a pusher.?
bob
Add on to my last post, My 35 foot A also has air bags in all 4 corners and Koni Shocks, I just love them and they were worth the 700 dollars invested. the air bags are also nice for Loading help but not for overloading. bob
bob
what cost? and is it easy to do yourself? I guess Roadmaster in Oregon can send one ifyou want to buy it. They are great people. I drive a 35 foot Workhorse class A and it doesnt sway much on the road, would it help me for the cost? bob
Dalton Tamney
This is exactly the kind of information I am interested in. I have spent 20+ years pulling various sizes of travel trailers and suffered the effects of sway, especially from heavy crosswinds. It wasn’t unitl I finally gave in and bought a Hensley hitch that the problem was finally solved. I plan on moving up to a Class A in the next few years and I don’t want to have to learn by bitter experience again how to solve a sway problem. Are there any other things I can do, in addition to a better sway bar, to solve the sway problem I am anticipating, eg air suspension, etc.?
Fredori
Where can I purchase one and have it installed? Just got back from the first trip in our 99 Ford chassis Itasca 36 ft motorhome, and the winds and trucks were horrible.