failure of sumo springs

[captmetal]

Failure of sumo springs

thor outlaw 2013 37ls

this is the accounting of the failure of sumo springs under normal use.

I had installed sumo spring in the summer of 2017 to reduce body like many have done before me. Having driven about 7000 miles with them, they seemed to do the job, also installed the 2nd rear sway bar from roadmaster and the trac bar from blue ox.,

this year the big trip to yellowstone and mt rushmore all went fine until the end of the yellowstone trip, i do not pull a car i drive the coach everywhere.

I don’t drive fast over bumps or do crazy abusive stuff, this was the first trip with the garage loaded to max 2500 lbs, it was noted that the rear of the coach dropped 1 inch in height with the load. .

In yellowstone there was some construction and driving on dirt roads nothing any worse the normal pot holes we find in the city. (driven at slow speed) there was one area that was very rough i drove it at 3 mph through the 200 feet or so of bad roads, the coach did sway from side to side in a extreme manner, 2 or 3 sways (but within range of a evasive highway maneuver.)

during a brake check stop ( yes the brakes got hot ) on the steep pass, it notice the sumo springs had moved out of there normal vertical position and where bulging out of position.

It was obvious that the sumo springs needed to be removed and i really did not want to do it on the side of the road unless there was no other way.

I was able to get the coach to cody, wy where i had a local truck shop remove the sumo springs.

As can be seen in the photos on driver side the super heavy frame bracket was bent out of shape, the frame bolts holding one side on was sheared off and the frame bracket was hanging and got bent out of shape.

The passenger side the lower spring bracket was smashed and bent massively out of shape and
the huge amount of grinding marks on the lower bracket, this rubbing was done by the oem sway bar link and it needs to be replaced also.

The tires seemed to make it with out any damage .

The lesson learned here is that maybe the sumo’s work and reduce sway, but under some type of maximum movement the sumo’s will fail.

The sumo’s may fit the f53 frame but failure of the mounting system will result in other damage as there is no extra room for the sumo’s to move out of position. The rear tires could have easily been damaged for a later down the road nasty tire failure.

Since i drove the coach for 2000 miles after removal of the sumo’s i am not sure anymore if they are really needed, there seems to be a bit more body movement, semi’s passing mostly does nothing, crosswinds can be tricky i had some severe crosswinds during a eastern colorado route on my return.

It would be wise to check your coach for the condition of the sumo’s, i am amazed at the very heavy brackets being bent and the mounting bolts being sheared off, the forces here are incredible

[ArrrV]

Wow!!! What was Sumo's response? I found them to be very responsive and helpful when I needed their guidance before installing front and rear on my ACE last year. My first reaction is that your rear axle was overloaded--max capacity is still limited by the max load per axle. Did you weigh the coach before the trip to make sure you were within the weight allowances? Glad you made it back safely. We did that trip summer of 2016 with the grandkids and it was spectacular.

[Chance]

Originally Posted by captmetal

....cut.....

In yellowstone there was some construction and driving on dirt roads nothing any worse the normal pot holes we find in the city. (driven at slow speed) there was one area that was very rough i drove it at 3 mph through the 200 feet or so of bad roads, the coach did sway from side to side in a extreme manner, 2 or 3 sways (but within range of a evasive highway maneuver.)

.....cut....

Apples and oranges. With all due respect, this is exactly what I’ve warned against many times when “upgrades” are made to reduce body roll without considering what happens when the suspensions’ ability to articulate is reduced significantly.

When a motorhome leans or rolls side to side during a highway maneuver on relatively flat surface, the front and rear suspensions are not fighting each other, so all that extra roll stiffness added by stiffer sway bars and Sumo Springs isn’t that bad. However, when the road surface isn’t flat, like what you experienced in Yellowstone driving off-road, the front suspension may want to pivot (articulate) in one direction and the rear in the other direction, and if prevented from doing so by excessive suspension stiffness, something has to give.

Having said that, this failure should not have occurred solely because of stiffer sway bars since that in itself should spread load on Sumos even if it meant motorhome wheels lifted off road. My biggest concern with these types of “upgrades” is that while they reduce roll, and improve crosswind handling, they also add loads (forces) throughout the motorhome that few of us can predict or understand.

Driving off-road isn’t the only limitation. The same can happen when smooth pavement isn’t flat. The front wants to roll one way, the rear the other way, and add-ons are there to prevent it.

[Beau388]

It appears the brackets are the same by coach manufacturer, and year but not chassis weight. For the front Sumos, that difference is not significant at 1,250 lbs per wheel for the lightest to the heaviest F-53 chassis. The rear difference, however, is 3,250 lbs per wheel. I know how easily my 18,000 lb coach is to overload the rear axle, especially when going out for a week of dry camping. Just saying....

[vegasruv24.1]

Originally Posted by captmetal

Failure of sumo springs

thor outlaw 2013 37ls

this is the accounting of the failure of sumo springs under normal use.

I had installed sumo spring in the summer of 2017 to reduce body like many have done before me. Having driven about 7000 miles with them, they seemed to do the job, also installed the 2nd rear sway bar from roadmaster and the trac bar from blue ox.,

this year the big trip to yellowstone and mt rushmore all went fine until the end of the yellowstone trip, i do not pull a car i drive the coach everywhere.

I don’t drive fast over bumps or do crazy abusive stuff, this was the first trip with the garage loaded to max 2500 lbs, it was noted that the rear of the coach dropped 1 inch in height with the load. .

In yellowstone there was some construction and driving on dirt roads nothing any worse the normal pot holes we find in the city. (driven at slow speed) there was one area that was very rough i drove it at 3 mph through the 200 feet or so of bad roads, the coach did sway from side to side in a extreme manner, 2 or 3 sways (but within range of a evasive highway maneuver.)

during a brake check stop ( yes the brakes got hot ) on the steep pass, it notice the sumo springs had moved out of there normal vertical position and where bulging out of position.

It was obvious that the sumo springs needed to be removed and i really did not want to do it on the side of the road unless there was no other way.

I was able to get the coach to cody, wy where i had a local truck shop remove the sumo springs.

As can be seen in the photos on driver side the super heavy frame bracket was bent out of shape, the frame bolts holding one side on was sheared off and the frame bracket was hanging and got bent out of shape.

The passenger side the lower spring bracket was smashed and bent massively out of shape and
the huge amount of grinding marks on the lower bracket, this rubbing was done by the oem sway bar link and it needs to be replaced also.

The tires seemed to make it with out any damage .

The lesson learned here is that maybe the sumo’s work and reduce sway, but under some type of maximum movement the sumo’s will fail.

The sumo’s may fit the f53 frame but failure of the mounting system will result in other damage as there is no extra room for the sumo’s to move out of position. The rear tires could have easily been damaged for a later down the road nasty tire failure.

Since i drove the coach for 2000 miles after removal of the sumo’s i am not sure anymore if they are really needed, there seems to be a bit more body movement, semi’s passing mostly does nothing, crosswinds can be tricky i had some severe crosswinds during a eastern colorado route on my return.

It would be wise to check your coach for the condition of the sumo’s, i am amazed at the very heavy brackets being bent and the mounting bolts being sheared off, the forces here are incredible

I can see from the pic these were not installed correct, have who ever installed these fix it..

[vegasruv24.1]

also, you stated this.;

"I had installed sumo spring in the summer of 2017 to reduce body like many have done before me. Having driven about 7000 miles with them, they seemed to do the job, also installed the 2nd rear sway bar from roadmaster and the trac bar from blue ox.,"


but then you say damage was done by the stock oem sway bar???

[Kev]

I have them on all my coaches with good results. Never had a problem.

[vegasruv24.1]

I wanted to add, I'm in vegas, and if anyone has a problem with a sumo product,.. hit me up and I'll get you back on the road..

[Winnie]

Have a 24.1 Vegas with a steering stabilizer, but it does roll on uneven highways, so wondering what I can do to reduce it. Other than that, we love this coach!!

[Beau388]

Originally Posted by Winnie

Have a 24.1 Vegas with a steering stabilizer, but it does roll on uneven highways, so wondering what I can do to reduce it. Other than that, we love this coach!!

This movement is known as "sway". The only way to reduce sway is stiffen (increase) the spring rate. Selectively this done by an sway bar or anti-roll bar between the springs. This bar can be installed in the front, rear or in both places. This bar effectively increases the spring rate on the spring on the outside of a turn and decreases the spring rate on the inside spring. This does effect the ride quality, but not usually to a noticeable amount. Sumo springs do the same by increasing the spring rate. The Sumo Springs are longer and softer then the bump stops they replace, so the contact the springs earlier limiting spring travel. Sumo Maxims are longer and stiffer and come with special brackets that allow the springs to stay in contact with the springs at all times. This means they reduce sway by compressing when the coach leans to the outside of a turn and stretches resisting the lean on the inside of a turn.

The problem is basically your body is not used to being 5 ft above the roll center of the vehicle, so you are not used to the 5 times greater movement than in a car or small truck.

[Rich1339]

2019 hurricane 29m. What model/make of Sumos are recomended ??? Tx in advance.

[electric]

Originally Posted by Beau388

The problem is basically your body is not used to being 5 ft above the roll center of the vehicle, so you are not used to the 5 times greater movement than in a car or small truck.

This is a great explanation and advise. I'm new to driving a huge box, so my initial experience is not pleasant, causing me to believe I need suspension upgrades, especially with forum full of such solutions. But maybe the problem is lack of proper experience and adjustment is needed between my ears rather than suspension. I think I'll hold off any suspension upgrades for now.

[16ACE27]

Originally Posted by electric

This is a great explanation and advise. I'm new to driving a huge box, so my initial experience is not pleasant, causing me to believe I need suspension upgrades, especially with forum full of such solutions. But maybe the problem is lack of proper experience and adjustment is needed between my ears rather than suspension. I think I'll hold off any suspension upgrades for now.

Excellent analysis! Body roll will always exist on a MH. The new MH driver is not used to it and is terrified of the feel of a rolling coach and seeks to stop it, hence the market for all the after market suspension upgrades.

I was just thinking about this today as I was driving the Blue Ridge Parkway up and down the mountains, around the curves, and occasionally through some wrinkled roadway sections. It's quite a workout on the MH and driver and although I have quite a few miles under my belt on interstates and lower altitude roads this was a new experience for me. Yet here I was a week into driving these mountain roads and my comfort level was so much higher than when I started because i was used to the way the MH handled the direction and road changes. It doesn't roll any less but I am used to it and know what to expect, so my reflection was; how little of an anxiety raiser it had become.

The only "suspension" upgrade I have is the Roadmaster steering stabilizer.

[Beau388]

Originally Posted by 16ACE27

Excellent analysis! Body roll will always exist on a MH. The new MH driver is not used to it and is terrified of the feel of a rolling coach and seeks to stop it, hence the market for all the after market suspension upgrades.
The only "suspension" upgrade I have is the Roadmaster steering stabilizer.

I remember watching a sports car race in 1963 in Fort Sumner AP, NM; it was the under 1500 cc race. The were Porsche 356 Supers, Alfa Romeo Giulias and one Isuzu Bellel sedan. The Porsches corner almost flat, The Alfas leaned a little more but not any more than my Fiat Abarth 750. The Isuzu leaned so far in the right hand turns I thought the drivers side door handle would touch the pavement. When the Isuzu passed the Porsche on the outside of a right hand 120 degree turn, I was blown away. It was later I learned the Isuzu had Bosch direct cylinder fuel injection (same system as the Mercedes 1956 300 SL), so there was no fuel cutout on the hard cornering. The lean allowed a more compliant suspension to cope with the bumpy, AP's concrete surface (built in 1942);thus much better traction. Body roll is not all that bad if you want a smooth ride and better cornering on a rough road.