How do I stop F53 from rocking from driver side to passenger side?

[Gypsy9978]

We have a 2018 Bounder 35k. On a trip with road construction we were routed to the shoulder of the road which had a slant towards the grassy edge of the shoulder. As we would hit rough pavement the motor home would bounce from side to side and it felt like it was going to tip over towards the passenger side. This was so scary and felt like a safety issue. Is there anything we can install to stop or reduce this side-to-side bouncing?

[twinboat]

Look up the cheap handling fix or CHF.

It is a simple modification to the anti sway bars end links, to help limit exactly what your experiencing.

[macnut]

I added sumo springs that solved the problem. They are about $1200, so the cheap handling fix (CHP) beats on price!

[Rolling Ragu]

It is very common, even on new F53 coaches, that the rear sway bar can become loose. I would check that both sway bars are operating correctly (attached).

We bought our 2011 about 4 months ago. We had the same fear of tipping over that you have. I went underneath and discovered that our rear sway bar wasn't attached on one side and the entire bracket was gone!

This past weekend, I replaced the bracket with new bushings and did the CHF on the front sway bar. Per my wife, the improvement was "drastic". I'm very pleased.

Something for you to check.

[Gypsy9978]

Thanks everyone.

After the CHF and/or installing sway bars, what would be the next thing to try? What issues do Summo Springs address? And what problems would Koni shocks fix? I don't understand the differences between springs and shocks.


And if shocks would help this issue, would Koni or Bilsteins be better?

[WyCamper]

The CHF solved the issue on my Vista. It was free, and made enough of a difference that I can't think of any reason to throw money at it on top of that. Do the CHF first and then go from there, chances are you won't need to buy more parts.

While I was doing the CHF I also backed out the bracket bolts on both front and rear, added some blue threadlock, and torqued them back down to 65ft/lb.

[TeJay]

Gypsy,

"After the CHF and/or installing sway bars, what would be the next thing to try? What issues do Summo Springs address? And what problems would Koni shocks fix? I don't understand the differences between springs and shocks.

And if shocks would help this issue, would Koni or Bilsteins be better?"

First of all do one thing at a time so you can more accurately evaluate its effect on ride & handling.

Sumo's are used to basically add more SWAY control. They are a progressive type of rubber or plastic. With some weight they compress. Once the added weight becomes enough the plastic becomes harder to compress so the Sumo's resist more compression. Similar to any type of spring but they probably won't oscillate like a spring.

We added Sumo's to the front but I honestly couldn't tell much difference. Others report they like how they helped. As with most MODS not everything works as well on all RV's. That's based on the fact we are not always comparing apples to apples. There are so many variations between RV's: weight, length, overhang, location of appliances, and storage compartments, etc, etc.

Our last MOD was adding a front RSSA steering shock with large coil spring. That helped a lot with the wind in general and of course the approaching semi's.

A spring no matter if it's a torsion, coil or leaf supports weight and cushions the ride. Most springs are called progressive. The more it compresses the more it resists compression.

Shocks only dampen the leaf springs oscillations created by driving down the road. The energy stored in a compressed spring has to be released either by heat created by the shock stopping the oscillations or the vehicle continues to bounce down the road until all the energy has dissipated. Since you'll encounter other road bumps and holes without shocks that's all you'll do is just bounce down the road.

If you read enough threads and posts concerning the different manufacturers of shocks for RV's a greater percentage of owners prefer the Koni's over the Bilsteins. It's probably about 80% for Koni's and 20% for Bilsteins.

[RRR]

Originally Posted by Gypsy9978

Thanks everyone.

After the CHF and/or installing sway bars, what would be the next thing to try? What issues do Summo Springs address? And what problems would Koni shocks fix? I don't understand the differences between springs and shocks.


And if shocks would help this issue, would Koni or Bilsteins be better?

The next thing IMO if the CHF doesn't make you happy the next thing for sway is the addition of a second rear way bar. I used Hellwig from sdtrucksprings.com over Roadmaster from etrailer.com as the size was the same price lower and the RM were on BO.

As far as the Sumos I added them too but I felt the cost/benefit ratio wasn't worth it. But it seems YMMV on every situation.

[Gypsy9978]

Thanks everyone! Greatly appreciated.

[R.Wold]

I'd do the CHF first as everyone has said, and Im from the keep-the-geometry-as-close-to-original-as-possible school of thought, so Id use the Hellwig adj links (part # 7962 around $100) on the front, use the front links on the rear, and use the bushings from the original rear links in the Hellwig links up front (you have to read quite a few pages of the CHF thread to really glean all the finer points). You'll probably be done with sway. I think this is superior to add-ons like sumo springs because its improving the existing system, rather than adding another one.

The next thing to look at is a rear track bar (you probably have one on the front). It will help keep the rig in line when being passed by 80mph busses and in heavy cross winds. Different situation, but the next logical handling improvement. But they seem to run about $500 and I have yet to see one that looks like its worth the price, so I'll probably fabricate my own.

My coach is old enough (9 years) for new shocks so its getting Bilsteins, but I dont expect to see any miraculous improvements from them - just using quality replacement parts. With a 2018 your shocks are most likely doing what they are supposed to do and will continue to do so for quite some time.

This "dual sway bar" thing concerns me - you'd have two different rates of tension/compression at the same time. I suppose the weaker one would be contributing to the effort, but why bother? Chances are the original bar with the link in the new location will be more than adequate. And two bars is just extra weight, parts, maintenance, cost, etc.

A lot of folks add various steering stabilizers to their rigs but here again, you probably dont have that problem. Proper tire inflation and wheel balance should be looked at first if you do. But there are some good products out there - if you do choose to add one Id use one that is similar in design to OE but just increased dampening.

So thats my .02 worh on F53 handling. I agree - stock its unwieldy at best and dangerous at worst. I just had a similar very unpleasant experience on 215 South out of Salt Lake City, hence the CHF.

[Rolling Ragu]

Sorry for a brief hijack. Is the condition of shocks affected by age? or mileage? I bought a 7 year old coach with 10k miles. I assume the shocks don't "age with age".

[twinboat]

Originally Posted by tragusa3

Sorry for a brief hijack. Is the condition of shocks affected by age? or mileage? I bought a 7 year old coach with 10k miles. I assume the shocks don't "age with age".

Shocks age by leaking out the oil used to dampen the rebound of the springs or internal breakage.

Look for oil seeping out of the top and drive slowly over a speed bump and see if the rig bounces more then once.

[jharrell]

Originally Posted by Gypsy9978

Thanks everyone.

After the CHF and/or installing sway bars, what would be the next thing to try? What issues do Summo Springs address? And what problems would Koni shocks fix? I don't understand the differences between springs and shocks.


And if shocks would help this issue, would Koni or Bilsteins be better?

Springs store kinetic energy and shocks convert kinetic energy to heat energy, energy cannot be created or destroyed. There is no such thing as a perfect spring or a perfect shock they each can act a little like the other. When your suspension moves due to terrain or wind or turning the shocks and springs both resist the movement, the resistance is the spring or shock accepting the energy. The higher the resistance the more energy will be stored or converted per inch of movement, conversely this increases the force per inch.

Without shocks your suspension would oscillate back and forth for some time after hitting a bump or leaning as the spring stores the energy then releases it back until it stretches the opposite direction storing it again and so forth. Since the spring is not perfect it will convert a very small amount of energy to heat like a shock slowly dissipating it, not pleasant, takes too long.

Without springs your shocks would convert what energy they can to heat then the rest would go into the frame once it bottoms out and your vehicle would stay bottomed out, not pleasant.

So your springs and shocks work together. Springs hold your vehicles suspension at proper ride height by resisting enough force equal to the weight on the axle at rest then when encountering a bump or other movement that imparts more force both they and the shock accept the energy dividing it between them. The shock converts its share to heat to get rid of it, the spring stores it for later use by the shock on rebound. In the end a good ride is about getting rid of all the energy put into the suspension through the shock and not the vehicle.

The ideal is for the suspension to move as much as possible without bottoming out lowering the forces for the same energy therefore absorbing bumps. The problem is your suspension doesn't know the difference between a bump moving the suspension or your vehicle leaning due to wind or turning. The lean is called sway or body roll. Stiffer springs or or shocks will resist sway but will also resist bumps creating a harsher ride.

To counteract sway two common techniques are used. The first which nearly all modern vehicles use is called a sway bar. This is a secondary torsion spring where the ends are attached to each side of the axle rather than one end on frame and the other on axle. The sway bar is only twisted when the axle articulates (one side is different from the other). This articulation occurs when the body leans and on bumps that are different on each wheels but does not occur on bumps that affect both wheels equally (rail road track, expansion joints, etc.). Therefore the sway bar reduces suspension travel under certain conditions reducing sway while allowing full travel under others such as expansion joints. This is not perfect as an uneven bump will be resisted more than it should leading to a harsher ride in those circumstances, it is a compromise.

The second technique is variable damping in the shock based on the frequency of the suspension movement. Sway tends to be a relatively slow movement while bumps tend to be a quicker movement. Shocks such as Koni FSD (Frequency Selective Dampening) have mechanical valving that tries to open up for quick movements while close down for slow movements reducing sway while still being compliant for bumps. Reviews are mixed on their effectiveness, its hard for a purely mechanical system to anticipate properly.

More advanced techniques usually involve active computer controlled springs or shocks (high end air suspensions, liquid springs) whereby the computer is making decisions about what type of movement is occurring and adjusting accordingly.

Some people attempt to reduce sway by adding helper springs(air bags or Sumos). These springs augment the existing leaf springs increasing total spring rate all the time. This swill reduce sway just like a sway bar, but unlike a sway bar they will be active over even bumps like expansion joints too while a sway bar will not. These are not recommended for sway control unless stock springs are too weak allowing bottoming out under normal conditions. They are typically for vehicles whos springs are too soft for the load due to being undersized (Pickup trucks) or old and worn. Air bags can be adjusted for load at any time while Sumos are fixed.

The easiest thing to do on the F53 to reduce sway is the CHF. The F53 comes from the factory with adjustable sway bars with two positions, they are always set on the softer outer position from the factory. By moving the links to the inner position you shorten the lever that twists the torsion spring reducing leverage which increase its stiffness. After market sway bars will be thicker increasing their stiffness. Secondary sway bars increase total stiffness by adding both together in parallel. The end result is the same, which is why the CHF is so popular as it cost nothing other than time.

If you opt to extend your links when doing the CHF you are simply undoing some of the CHF by lengthening the effective lever arm. The stiffiness of the torsion spring is not only determined by the lever arm length but also the angle of force. When you move the link point inward without extending the link the lever angle changes away from 90 degrees. When applying force to a lever 90 degrees has maximum leverage, leverage goes down as angle moves away from 90. Stiffening the sway bar is about reducing leverage. The CHF without link extension has less leverage than it extended to 90 and is therefore stiffer. The attachment points are circular bushing they do not care about angle, think piston rods and bearings and crank. The only concern is that your wheels may be pulled off the ground sooner by jacks as the sway bar and links reaches 180 degrees sooner. There are some other differences related to the progressive rate that can be discussed further.

[RRR]

Originally Posted by R.Wold

...

This "dual sway bar" thing concerns me - you'd have two different rates of tension/compression at the same time. I suppose the weaker one would be contributing to the effort, but why bother? Chances are the original bar with the link in the new location will be more than adequate. And two bars is just extra weight, parts, maintenance, cost, etc...

You have some interesting points about the sway bar, as well as your other posts.

I guess that you will be really concerned with the triple sway bar setup that is available from Henderson's Lineup/SuperSteer. I was told by Roadmaster that they worked with Henderson on this.

And as far as your maintenance issue with the duel setup I don't understand.