MB Sprinter 3500 suspension issues

[AJMike]

I first posted this question on the Sprinter forum, but I got only a few responses and perhaps that is because the membership of that forum is smaller than here. In any case there are a number of Winnebago Cs built on the same chassis so perhaps I should post it here as well. Perhaps I will get a larger number of responses and more helpful information. Perhaps not, but here goes.

------

I have searched the forum for posts about this and found a lot about sumo springs and Koni shocks, but nothing that I saw answered my questions. I suspect this is a subjective kind of topic but I do need help and this seems like the best place to ask.

We recently bought a new (to us) 2020 Regency Ultra Brougham built on a 2019 Sprinter 3500 XD chassis. The ride is smooth and quiet, but it tends to wallow when turning, especially if there are any of those water runoff troughs in the road and, this being the Phoenix area, they are everywhere. I thought the best idea to dampen the wallowing would be to do something about the springs, shocks or steering, but was uncertain which was the most likely to give the best return. I called one local shop and they told me to replace all three at the same time and that doing only one would not solve the problem. I called another shop and was told that the steering stabilizer was the most important thing to take care of and the best place to start.

Both of these shops are places with good reputations. The first is a suspension shop and the second is probably the best independent full service RV repair shop in the area, but their advice are worlds apart, so I thought I would ask here to see what people who have had this done think is the best approach. Will addressing one solution make much difference? If so, which is the best place to start? Or will replacing only one item make replacing subsequent items more difficult?

The local price to take care of all 3 was $3200 and that is a lot of money to me so I would want to know it was the best approach before spending that much. The steering stabilizer cost was much less, about $1000, and thus more financially doable for us, but I don't want to end up making a false economic choice. My wife and I are both retired and RVing is our only real recreation so I am willing to spend what is necessary, but don't want to spend foolishly. Any advice would be appreciated.

[DavidM]

I am surprised you didn't get much of a response in the Sprinter forum. Were you posting to a particular Sprinter chassis subforum like the VS30 or the NCV3 ones. What exactly is "wallowing"? MH suspensions react several ways:

Sway or tilting when a truck passes or you make a sudden lane change. This is best handled by adding a sway bar or a thicker sway bar.

Wandering- The suspension doesn't track well. It always needs corrections to stay on track. This is best handled by an alignment (most of the discussion on this point is on Ford chassis but it may also be applicable to Mercedes) to add more caster which centers the wheels. A Safe T Plus or Roadmaster Reflex stabilizer and centering spring device is also a potential solution.

Bouncing. The suspension reacts to dips and bumps and goes up and down a few times before settling down. Better shocks will help this problem. Also Sumo springs which also dampen bouncing can help.

Also read iRV2 in the appropriate Sprinter section. This thread might help- https://www.irv2.com/forums/f280/hel...gs-538225.html

David

[lenore]

I added the Sumo springs and Hellweig sway bar. It made night and day difference on my Vita which is very tall at 11ft 6 inches. I will tell you I installed both myself, it was not difficult and if you have a friend or somebody you trust you would be hundreds cheaper. Trucks no longer bother me. I also had a alignment done and highly recommend this. These three tasks are discussed a lot on the Vita site and everyone agrees there is improvement in the driving of the Mercedes chassis.

[ZimBob]

Originally Posted by AJMike

Will addressing one solution make much difference? If so, which is the best place to start? Or will replacing only one item make replacing subsequent items more difficult?

My wife and I own a 2013 Forest River Solera 24R also built on the MB 3500 chassis (we are upgrading to a new Winnie Adventurer 29B as soon as Ford can get their recall issues fixed).

I have not done the upgrades that you are considering, so I'm afraid I can't provide guidance as to what works and what doesn't (sorry!). With that said, my opinion is that the Sprinter chassis is stable enough out of the box that I would start small. I hope a small change at a low cost may make enough positive difference that you won't have to invest further.

For more advice, consider hopping over to the Sprinter chassis forum on IRV2. I suspect this topic has been covered over there quite a bit, as well.

Wishing you smooth sailing!

[AJMike]

Originally Posted by DavidM

I am surprised you didn't get much of a response in the Sprinter forum. Were you posting to a particular Sprinter chassis subforum like the VS30 or the NCV3 ones. What exactly is "wallowing"? MH suspensions react several ways:

Sway or tilting when a truck passes or you make a sudden lane change. This is best handled by adding a sway bar or a thicker sway bar.

Wandering- The suspension doesn't track well. It always needs corrections to stay on track. This is best handled by an alignment (most of the discussion on this point is on Ford chassis but it may also be applicable to Mercedes) to add more caster which centers the wheels. A Safe T Plus or Roadmaster Reflex stabilizer and centering spring device is also a potential solution.

Bouncing. The suspension reacts to dips and bumps and goes up and down a few times before settling down. Better shocks will help this problem. Also Sumo springs which also dampen bouncing can help.

Also read iRV2 in the appropriate Sprinter section. This thread might help- https://www.irv2.com/forums/f280/hel...gs-538225.html

David

I suppose I should have been clearer about what I meant, so I will try now.

The vehicle ride is comfortable, although a bit soft. On one hand it is far more comfortable on a good road than the Fuse, and certainly quieter at highway speed. Not nearly as much wind noise.

It behaves well when traveling straight and when turning provided the road is flat, but when I turn and there is a significant change in slope or, especially, when I turn and the road has one of those water runoff troughs (which are pretty much everywhere on the city streets, this being the desert) the vehicle sways left and right pretty badly. Enough that my wife is nervous that we are going to tip over on the side. Of course it is not actually that bad, but the sway is much more noticeable than it was with the Fuse.

The other problem is when the area is open and flat, but contains small rises and drops. That is, when we are boondocking (and we do that a lot) if the area is not truly flat had has noticeable depressions it acts the same way as above - truly noticeable sway left and right. And that is what I am trying to fix.

There really is not much of a problem when on the highway, even with passing trucks. Then it is pretty well behaved. Sway, but nothing that I consider to be serious enough to take into the shop for work.

[creativepart]

Mike, I'd lean toward adding a bigger anti-roll bar (sometimes called a sway bar). User Lenore above mentions the Hellwig sway bar and that is a very good one. Roadmaster makes one as well. But Hellwig's is beefier.

The anti-roll bar is like a big U-shaped thick steel bar that's has it's arms attached to the axle and the flat section attached to the body. When you go over an uneven surface as the body leans to one side the arm of the sway bar on that side counter acts the leaning motion. Done right an anti-roll bar does just that... keeps the body from rolling. It won't stop all sway and roll but it will slow it, minimize it and keep things on a more even keel.

The best thing - it doesn't negatively effect the ride quality at all.

Sumo springs do similar things but do stiffen the ride making it harsher.

Hellwig Sprinter Sway Bar:

https://realtruck.com/p/hellwig-rear...bars/hwg-7254/

[DavidM]

Mike:

What you describe is sway, the leaning of the coach due to road changes or abrupt steering changes.

As Creativepart notes, the Hellwig sway bar would be a good solution, maybe combined with better shocks which will slow down the sway. Sounds like you don't need the steering stabilizer.

David

[bigb]

There have been a lot of threads on the Sprinter suspension at SprinterSource, do a Google search and include "Sprintersource" and you will get some hits. Member Calbiker seems to have quite a bit of knowledge. Old Crows had some good input as well and was a member here too but unfortunately he has recently passed away, but he left us with a lot of good info.

[Elkman]

Start with the heavy duty version of the front and rear SumoSprings which take less than an hour to install and this can be done by anyone. At one point the rear sway bar was beefed up and so less need to replace it with the Hellwig sway bar.

Dubious about shocks as the purpose of the shock is to provide dampening of the springs and they do not increase load capacity.

When the OCCC is less than 1000 lbs and this figure includes people and fresh water and supplies it is clear that the chassis load is 100% of its engineered capacity and so small wonder that it challenges the driver. It is why my next choice of motorhome is one built on the Ford E-450 chassis.

[mdstrum]

Check out AGILE OFF ROAD RIP PACKAGE...Sumo springs were waster of money for us, with our ERA 2019 4X4...AGILE RIP Made a HUGE improvement!!! https://agileoffroad.com/

[winniethepoo]

Originally Posted by Elkman

....
When the OCCC is less than 1000 lbs and this figure includes people and fresh water and supplies it is clear that the chassis load is 100% of its engineered capacity and so small wonder that it challenges the driver. It is why my next choice of motorhome is one built on the Ford E-450 chassis.

I corresponded with a suspension specialty shop and this is exactly what they said. That is, that the Sprinter based motor homes are right at their max load capacity, or, often exceed their max load. He continued that this will not only cause rocking of the motor home, but, also will fatigue the suspension components over time resulting in sag of the rear of the coach. Then, you'll bottom out more and more easily over time resulting in the dreaded rear end BANG over expansion joints and pot holes.

He said the solution is not only new shocks and recommends KONI FSD's, plus heavy duty Sumo's but also said that new leaf springs would be needed to correct for the ultra heavy load.

I haven't done this...yet. It is pretty costly and am unsure of the result. But, the ride of our Sprinter coach is dreadful on any roads that have and perpendicular cracks.

[BadMed]

I had the same problem with my 2020 View. Our coach would sway terribly when entering/exiting gas stations or going over the smallest pothole. The 2020 View model comes stock with a sway bar. So, rather than replace the stock sway bar with a Hellweig sway bar (or something similar) I elected to add an additional sway bar, the Roadmaster Auxiliary Anti-sway bar. The stock sway bar is mounted behind the differential and the Roadmaster Auxiliary sway bar is mounted in front of the differential. I also replaced the rear stock shocks with Koni FSD Shocks. I went with replacing the shocks with the Koni Shocks vs installing Sumo shocks because I have seen a lot of reviews that say they don't last very long (they are made of a high density foam). The new suspension parts eliminated nearly all of the sway. Also, I didn't think my coach had a tracking problem, but after the suspension upgrades it drives straight down the road and is a joy to drive. So glad I did these suspension upgrades. The parts cost was $970 through the Sprinter Store and installation was $330

[AJMike]

Originally Posted by mdstrum

Check out AGILE OFF ROAD RIP PACKAGE...Sumo springs were waster of money for us, with our ERA 2019 4X4...AGILE RIP Made a HUGE improvement!!! https://agileoffroad.com/

The link does not take me anywhere and all I get is a screen message -

/nfs/c12/h04/mnt/221929/domains/agileoffroad.com/html


Same thing happens when I type in Agile Off Road and follow the website link.

[Elkman]

Sway is from the suspension on one side having to take on more than 50% of the load, either in a turn or with side loading from wind. There is no reserve capacity with the Sprinter 3500 suspension and a class C coach mounted to the chassis.

The Sumo Springs only result in the suspension bottoming out sooner and so there is less travel but they do not add to load capacity. Fox shocks will slow the rate of load shifting and may improve the sense of control by the driver but they too are not increasing load capacity which what is needed. Adding more rear leaf springs might be a partial solution but I would talk to the people at SuperSprings to find out what they recommend for the Sprinter 3500 suspension and any caveats.

[AJMike]

Originally Posted by Elkman

When the OCCC is less than 1000 lbs and this figure includes people and fresh water and supplies it is clear that the chassis load is 100% of its engineered capacity and so small wonder that it challenges the driver. It is why my next choice of motorhome is one built on the Ford E-450 chassis.

As far as I can tell the OCCC of this RV is more like 1500 pounds. The curb weight is listed by the manufacturer as 9500 pounds and the GVWR is 11,030 pounds which gives me a figure of 1530 pounds. That actually seems like quite a bit for a B+, but I will weight the loaded RV and see what the actual figures are.

My guess is that we don't add more than 1000 pounds to the RV when fully loaded, including ourselves and a full load of fresh water and a full propane tank so I suspect we are well under the limit.

[AJMike]

Originally Posted by Elkman

The Sumo Springs only result in the suspension bottoming out sooner and so there is less travel but they do not add to load capacity. Fox shocks will slow the rate of load shifting and may improve the sense of control by the driver but they too are not increasing load capacity which what is needed. Adding more rear leaf springs might be a partial solution but I would talk to the people at SuperSprings to find out what they recommend for the Sprinter 3500 suspension and any caveats.

My first step will be replacing the sway bar with the Hellwig version, and I will see how that affects the RV sway, but I don't really know what to expect. For the moment I do not have any other changes in mind and based on what I understand the OCCC to be I am not particularly worried about increasing load capacity. If we really have 1500 pounds of leeway we should be good to go.

I am a bit puzzled by your comment about Sumo Springs. In an earlier post you recommended using heavy duty Sumo Springs but here you comment that only result in the suspension bottoming out sooner, and that does not sound like much of a recommendation. So what are you suggesting about them - use them or not use them?

[bigb]

Originally Posted by BadMed

I had the same problem with my 2020 View. Our coach would sway terribly when entering/exiting gas stations or going over the smallest pothole. The 2020 View model comes stock with a sway bar. So, rather than replace the stock sway bar with a Hellweig sway bar (or something similar) I elected to add an additional sway bar, the Roadmaster Auxiliary Anti-sway bar. The stock sway bar is mounted behind the differential and the Roadmaster Auxiliary sway bar is mounted in front of the differential. I also replaced the rear stock shocks with Koni FSD Shocks. I went with replacing the shocks with the Koni Shocks vs installing Sumo shocks because I have seen a lot of reviews that say they don't last very long (they are made of a high density foam). The new suspension parts eliminated nearly all of the sway. Also, I didn't think my coach had a tracking problem, but after the suspension upgrades it drives straight down the road and is a joy to drive. So glad I did these suspension upgrades. The parts cost was $970 through the Sprinter Store and installation was $330

Can you link which shocks you got? Also I like the AUX sway bar idea but I can't afford to add that much weight so if I do anything with the sway bar it will probably be replacement of the original to minimize the weight gain.

[BadMed]

Here is a link to the Koni FSD rear shocks: https://www.sprinterstore.com/produc...sis-sprinters/
I would highly recommend adding the Roadmaster Auxiliary sway bar in addition to the shocks. It weighs 69 lbs. You can find it here: https://www.sprinterstore.com/produc...vans-1209-131/

[Elkman]

The SumoSprings do not increase load capacity of the Sprinter chassis but they do reduce sway by reducing the amount of motion between the coach and the chassis. Not a perfect solution but they do help and are worth the investment to buy and install.