23 replies to this topic

[Croft]

We are bordering on running overweight with our 2005, 31' Tioga Class C on a Ford E-450 chassis, towing a Honda Accord. It sways quite a bit on corners and speed bumps and when being passed by semi's. Loosing weight is not an option because "you never know when we are going to need all the stuff we have to take with us"!

I am thinking of either beefing up the springs or adding air bags. My local suspension shop says $500 to add a leaf to the springs and $600 for air bags. While searching the Internet for advice I came upon Supersprings, a supposedly DIY solution but costing about $750 here in Canada after shipping.

Any advice would be appreciated.

[Mike57]

We are bordering on running overweight with our 2005, 31' Tioga Class C on a Ford E-450 chassis, towing a Honda Accord. It sways quite a bit on corners and speed bumps and when being passed by semi's. Loosing weight is not an option because "you never know when we are going to need all the stuff we have to take with us"!

I am thinking of either beefing up the springs or adding air bags. My local suspension shop says $500 to add a leaf to the springs and $600 for air bags. While searching the Internet for advice I came upon Supersprings, a supposedly DIY solution but costing about $750 here in Canada after shipping.

Any advice would be appreciated.

The manufacturer weight rating for a rig is based on the ENTIRE suspension. Tires, rims, axles, springs, springs supports, frame support at the suspension etc. Beefing any one of those will make some of the symptoms appear to be reduced but the rest of the suspension will still take the hit.

Swaying can be improved with anti-sway bars (duuuuh!). I believe at least one manufacturer makes a support for the rear axle that prevents side to side motion but the above problem will still exist.

Time to lose the bowling ball collection or the collection of rocks from all the "special" places you have visited. Sorry!

[Stanley P. Miller]

Springs or airbags will get you a bit higher but likely won't do anything for the sway. If you go with a single-fill airbag system it will likely make the sway worse as air moves from side to side just opposite of what would be needed to stay level, individual bag fillers are highly recommended. I've used Ride-Rite bags on several Fords with good ride-height results and install is fairly easy.

http://www.firestone...l.com/riderite/


The first place I'd put money is on the heaviest shocks that will fit your rig, they won't stop long term leaning from going around a corner but they should help with short term stuff like speed bumps and passing trucks.

Adding heavier sway bars is an option but you tend to run into other issues if you just put on heavier bars, beefing up the mounts is probably a good idea if you go that route. Finding heavier bars can be hard and expensive too.

[Croft]

I should have spent more of my youth messing around with the mechanics of cars instead of just driving them! I really do not know where to start but I do know several people who have replaced their shocks so that sounds like good advice, thanks Stan. I probably should have added that our MH has only 40,000 miles on it.

The Bilstein site has a method for finding the right shock and I used it to find the heavy duty front and rear ones for my year and model. I will call them to make sure they are the right ones as well as being the heaviest available. They are $105 each with a deal on shipping right now at $5 each. This is probably a good place to start.

Link to Bilstein Canada

Edited by Croft, 03 May 2012 - 06:15 AM.

[geysergazers]

Ya, the heaviest shocks you can get. Preferably Bilsteins. Back-in-the-day they were the best for the Motocross boys and I’ll bet likewise today for your MH. Your chassis has big old sway bars, front and rear. Have someone take a close look at their bushings.

The E450 with that much house on it is testing the limit for sure but look at George running all these years at 3000# overweight. He has pounded the Kingpin Bushings our repeatedly and cracked the rear spring shackle mounts but so what. The real safety hazard running chronic overweight is Tires, though. I’d be real sure not to run tires over their capacity and I’d be using TPMS to make sure I’m never running a tire low&hot.


Lew

[Greg R]

How much would weak tire side walls contribute to this problem??

[Stanley P. Miller]

Properly inflated tires would not be much of a contributor, under-inflated they would be more likely to cause wander rather than sway.

[Kirk]

..... I probably should have added that our MH has only 40,000 miles on it.

With 40K miles on the OEM shocks, you probably have bad ones and that would contribute. I have no personal experience with them but most mechanically inclined motorhome owners that I know insist that the very best shock available for an RV is from Koni. I really think that if your situation were mine, I would do that first. If that don't solve the problem completely, the next thing that I would look at is a Trac-Bar.

[Jim Auguston]

I agree with Kirk. Based upon my experience with a 27' Class C on a Ford 350 chassis if your chassis does not have a rear trac bar that is the first thing to add. Henderson Line up explained to me that a sway bar would not help the truck passing sway at all. My chassis did not even have a rear sway bar and they said "Don't bother". The Trac bar made a huge improvement. For shocks the best and rather expensive are Koni FSD's. I removed Bilsteins with 25,000 miles on them and installed FSD's. Money well spent.

Jim

[David & Lorna Schinske]

For what it's worth.....

We have a vintage 30+ yo Midas Mini Class C (22 ft) on a GMC Vandura 3500 chassis. David installed a pair of these FIRESTONE AIR-ADJUSTABLE HELPER SPRING KITS on the rear. They were cheaper back in 2006 but even now still under $300 for the pair. It took about an hour to install both (including the break to drink a cold soda between sides... it was hot). I put 55lbs air in them. Class C now rides like a dream. Also Class C holds on the road better when passed and on rough roads. Even on I59 North of Birmingham AL! After the air bags, the Class C no longer felt like it was going to tip over on a curve or corner. We have leaf springs on the Class C. They were completely flattened out. The Class C is a tad heavy even when empty. It took a few trips to get the air to the right amount. Started out at 65 lbs. Went as high as 68 lbs and as low as 50lbs before deciding that 55 felt the best.


But that was just my experience. I'm the one who drove it. Now my 4' 10", 95 lb daughter drives it. So we may be wrong since it was a DIY install and also cost under $600. At the time, all the "experts" on the forums said we needed to do an expensive fix and that the air bags would not fix the lurching, swaying and teeth-jarring rattling. I hated seams in the pavement... it rattled the RV so badly that I thought it was going to fall apart. But this is what worked for us. The air bags are still on the Class C. It still rides great.

I'm sure someone here will point out how the air bags can't do what they do. This is what it did for us. There are some folks who refuse to believe anything I post and attack me on everything. So here's just another chance for them to do so. I would bet $$ that there will be someone who will post that this does not work, the Firestone Ride rite bags are garbage or my source for the bags sells bad ones and/or I am "mistaken" in my experience and how we must have put new shocks on (nope) or some thing similar (nope). Oh and I towed my 1995 Jeep Grand Cherokee with the Class C after the air bags. Since I did not tow before the air bags, I have no comparison but the Jeep towed great after the air bags were installed (no sway bar just a Stowmaster tow bar). But I'm sure someone will correct me there as well. They always do.

Gotta go build some window screens. Another thing I have been told you can't do on an RV. One of those "gotta buy them" things.

[Lou Schneider]

The E450 with that much house on it is testing the limit for sure but look at George running all these years at 3000# overweight.

Tioga George doesn't tow a vehicle, rarely travels above 45 MPH or goes more than about 25 miles at a time. And like you said he still breaks parts on a regular basis. Wonder why?

Edited by Lou Schneider, 04 May 2012 - 04:37 PM.

[Kevin H]

Croft - I put the Firestone air bags on my Dodge Ram 3500 to help with my camper. I put separate valves so each side is independent. I recently posted that I was getting a lot of 'squatting' in the ride. Replies said to boost the air. I did that and the ride is now where I want it. The air bags did work with the ride.

I read a lot and ended up putting Koni FSD shocks on my '99 Dolphin on a Ford F53 chassis. The ride has remarkably improved. I would do that again in a heartbeat. I got the shocks from shox.com. They were very knowledgeable and helpful with getting the correct shock.

The airbags were somewhere around $300. I bolted them on myself. No drilling or welding for my Dodge.

The shocks were around $650. Again, I installed them myself.

Good Luck and Happy Trails!! -- Kevin

[Croft]

Thanks for the tips everyone. I am parked now with no insurance on the rig so I have time to research a little more. Thanks again!

[Phil Saran]

My only experience with body sway was with the cab over camper on my F350 4x4.

To control it I went with a full set of Rancho 9000 9 way adjustable gas shocks and Firestone air bags on the rear
each with it's own fill line. This did control 90% of the sway.
Now that I'm back to a TT I'm thinking about removing the air bags.

[Ran D. St. Clair]

I would like to learn from this thread, so could somoene provide a more preceise definition of "sway". I hear all these terms and feelings (as in how the ride feels) being thrown around and I sometimes wonder if we are all even talking about the same thing. Are we talking about "roll" as in pitch roll and yaw, so the vehicle leans to the outside of a turn, or is pushed off vertical by a gust of wind from the side? Are we talking about some secondary effect where the roll transtates through the suspension geometry into a change in heading? Are we talking about some sort of dynamic interaction or oscillation, possibly something where the feedback loop includes input from the driver?

I can see how roll bars reduce roll. I can see how shocks can reduce roll so long as the force inducing the roll is only present for a brief time. I can see how making the suspension "stiffer" could decrease roll, possibly at the expense of other ride comfort parameters.

I suspect this discussion would be more useful if we talked about it more in terms of the laws of physics.

[Stanley P. Miller]

They are all interrelated. If the vehicle leans due to a gust of wind the wind also pushes it off line in addition to the directional change you get from the suspension in response to the original lean. In a curve you get lean which again impacts the suspension and the path of the vehicle. A side hill will feel similar to a curve as far as track and steering input go. Even ruts in the road can feed back through the suspension causing the vehicle to move side-to-side and lean making the impact of the ruts worse. Toss in the driver's steering input which can either help or hurt depending on their skill and you got a can-o-worms situation. Things will also vary from an independent front suspension versus a solid axle.

[Kirk]

Adding some to what Stanley stated so well, the type of RV involved also plays into the dynamics of those issues. It is a very fine line whether roll, lean or sway are the same issue, but all impact handling. When you consider a motorhome, the wheelbase ratio begins to impact this, particularly for a gas chassis because of the long overhang at the rear and the practice of many manufacturers to extend the rear frame-rails to build a longer RV on a short wheelbase. (With diesels that don't happen because of the rear engine in the way.) As the rear overhang extends farther behind the rear axle, the dynamics of things begin to change dramatically due to leverage. That means that the effects of wind and even road conditions get magnified far beyond what they would be if that practice was not used. When you apply force to the side the leverage at the rear will then push the front in the direction toward that force because of the greater rear impact. Rough roads then make the front experience a porpoise effect and suspension parts become far more critical.

Some of that same effect will apply to a trailer, but with a hinge point at the hitch, the effect becomes much different and is far greater for a travel trailer than a fifth wheel. That is the reason that a sway bar is so important when towing a TT.

[Ran D. St. Clair]

Thanks Stanley and Kirk. So sway = roll. I gather a sway bar, or anti-roll bar would be the most direct way to attack the problem. Stiffer suspension would also help but will also impact ride quality, possibly in a good way if the rear end is overloaded and squirming all over the place like a slug on gello. Stiffer shocks would help dampen oscillations in both pitch and role, but not reduce role when steady state side forces are applied. Air bags can increase stiffness and thereby reduce role if configured correctly. They can also take some weight off the springs which is a good thing if they are overloaded. They can also raise the ride height, which raises the center of gravity (slightly) which would make roll worse. Per Wikipedia, a sway bar on the rear axel can increase understeer, possibly a good thing if a long heavily loaded back end causes a tendency to oversteer. I accept that RV's are not race cars. Correct me if I got any of this wrong...

[Stanley P. Miller]

It is a complex situation, I'd look for an expert on the type of vehicle to see if there are known and working solutions other than the generic ones. I was thinking strictly campers above but Kirk made some good points on other vehicle types. I recall seeing things like replacement steering bits, axle stabilizers and similar stuff that were designed to address specific problems with specific vehicles.

If I had to pick one thing to do to a camper I'd go with heavy front and rear sway bars, doing both to try to maintain balance. With a truck and fiver the only thing I've fooled with is tire pressures and that helped a good bit. More pressure in the fronts and trailer tires, less in the rear duals resulted in a lot less impact from road-ruts. Motor homes I have not a clue.

I'd not directly equate roll and sway, if you get a steady roll to one side that does not cause interaction between the other forces involved you might not see any noticeable sway (unstable side to side movement) just the steady tilt.

[Kirk]

Ran D, My experience since becoming better versed on the weight and handling issues has been mostly with class A rigs but much of that should equate to a truck at least to some degree. I agree with Stanley that most of the best improvements tend to come from parts that were designed for a specific chassis, or chassis manufacturer. Ford class A chassis have long been known for solid handling but a very stiff ride, especially on the front axle. On the other hand, GM was known for a soft ride but major problems with wander and wind effects. Workhorse improved on that but was still a nicer ride but poorer handling when they stopped building gas chassis.

One other thing that I have found can play a part in all of this is the proper distribution of weight. If a motorhome is much heavier on one side than the other it very much impacts many handling issues. That same thing can be somewhat true for end to end weigh distribution as well. Class A rigs need to be properly balanced and the same thing can be true for a travel trailer. The proper share of weight on the tongue is very important and side to side can also if far enough off.