Sumo Springs on a 2007 Roadtrek Popular 210

[Roadtreker357]

The rear of a 210 has a metal “perch” between the axle and rubber bump-stop. When hitting a good bump, the bump-stop contacts the perch. After talking with someone in R&D at SuperSprings, I was sent an offset spring mounting plate that would move the spring further outboard and allow for more contact of the spring bottom with the perch. Without this modification, the spring ends up overhanging the inboard end of the perch too much. The perch is narrower than the spring, so the spring hangs over both sides of the perch. I don’t think the spring I received is one of their standard offerings.

To make the spring mounting plate end up parallel to the ground, a 4” disc is also needed to span the “ridges” on each edge of the frame. The disc goes between the spring mounting plate and the frame bottom.

The frame of the 210 at the mounting location has a frame sub member welded to the bottom of the main frame. The problem this caused is getting the correct mounting screw length. Too short (35MM) and the mounting plate nut could not enter the frame slot. Too long and the screw would hit the inner frame above the mounting slot before the mounting plate would be tightly fastened. I was provided with a 50mm screw and ended up cutting off 3/16” to ensure the screw would not hit the inner frame. A 45mm screw should be long enough to be able to get the mounting nut inside the frame, and short enough not to hit the inner frame.
The rear Sumo-Springs were installed first and raised the rear end almost 1”. This alone might help with the gas filling issues that sometimes occur to 210 owners. However, installation of the front Sumo-Springs raised the front, too, which caused the rear end to end up 5/8” higher than prior to Sumo-Springs installation. The front end was raised ¾”.

Rear Spring: 511411 raptor 4” sumo. Front spring: SSF-204-47

I’ve only taken the Roadtrek on a 20-mile drive, including some interstate with one 18-wheeler passing me. Also drove over some parking lot speed bumps. Sway to the side appears to be lessened on a turn and when passed by the truck. Speed bumps approached straight on, and not creeping, are harsh. These bumps approached at an angle and slower did pretty well. More long-distance trips needed to really evaluate the handling effects.

Photos (might need to rotate each 90 degrees clockwise):
Rear spring installed, before lowering the frame, perch below spring
Rear spring after lowering the frame
Rear spring, different view
Front spring compare to OEM spring (yellow)
Front spring installed, wheel still hanging down

 

[rowiebowie]

The 210 is problematic. It's bump stop "perch" is absent on the 190 and my Airstream Avenue where they rest directly on top of the axle.

Looks like the offset makes better contact, but time will tell if it tears up the bump stop. Worth a try if you can feel any difference in ride/handling.

Good luck.

 

[themexicandoctor]

The rear of a 210 has a metal “perch” between the axle and rubber bump-stop. When hitting a good bump, the bump-stop contacts the perch. After talking with someone in R&D at SuperSprings, I was sent an offset spring mounting plate that would move the spring further outboard and allow for more contact of the spring bottom with the perch. Without this modification, the spring ends up overhanging the inboard end of the perch too much. The perch is narrower than the spring, so the spring hangs over both sides of the perch. I don’t think the spring I received is one of their standard offerings.

To make the spring mounting plate end up parallel to the ground, a 4” disc is also needed to span the “ridges” on each edge of the frame. The disc goes between the spring mounting plate and the frame bottom.

The frame of the 210 at the mounting location has a frame sub member welded to the bottom of the main frame. The problem this caused is getting the correct mounting screw length. Too short (35MM) and the mounting plate nut could not enter the frame slot. Too long and the screw would hit the inner frame above the mounting slot before the mounting plate would be tightly fastened. I was provided with a 50mm screw and ended up cutting off 3/16” to ensure the screw would not hit the inner frame. A 45mm screw should be long enough to be able to get the mounting nut inside the frame, and short enough not to hit the inner frame.
The rear Sumo-Springs were installed first and raised the rear end almost 1”. This alone might help with the gas filling issues that sometimes occur to 210 owners. However, installation of the front Sumo-Springs raised the front, too, which caused the rear end to end up 5/8” higher than prior to Sumo-Springs installation. The front end was raised ¾”.

Rear Spring: 511411 raptor 4” sumo. Front spring: SSF-204-47

I’ve only taken the Roadtrek on a 20-mile drive, including some interstate with one 18-wheeler passing me. Also drove over some parking lot speed bumps. Sway to the side appears to be lessened on a turn and when passed by the truck. Speed bumps approached straight on, and not creeping, are harsh. These bumps approached at an angle and slower did pretty well. More long-distance trips needed to really evaluate the handling effects.

Photos (might need to rotate each 90 degrees clockwise):
Rear spring installed, before lowering the frame, perch below spring
Rear spring after lowering the frame
Rear spring, different view
Front spring compare to OEM spring (yellow)
Front spring installed, wheel still hanging down

Great post.

I love SumoSprings, great company & very interested in helping us Class B owners with improvements.

There was another thread here just 2 weeks ago that I believe spoke directly to this subject on the 210's or maybe it was just the rear sumos.

Please keep us posted.

 

[booster]

One thing that I will mention because it often gets overlooked in the evaluations and comments about, particularly, rear suspension improvements.


The two major things that are normally done, beyond simple shock absorber repair/upgrade are some sort of springing improvement and rear swaybar installation. Either one can be singly or together with the other.



The results I would expect, particularly in a Chevy, for adding Sumos to the rear would be a little bit of lift, maybe a bit more useful travel before hitting the huge overload lift so a bit less harshness, and a bit less wind sway and understeering wander.


An airbag addition instead of Sumos would give a bit higher (adjustable) height increase, a moderate amount of travel increase before hitting the overload leaf, and a low amount of sway improvement.


Adding just a bit swaybar in the back will not raise the height at all, not change the overload hitting distance, and will make a very large improvement in sway reduction and lessening of understeer.


You can mix and match these items to get what is adequate for you at minimum cost, or go for maximum improvement at a higher cost, or anything in between.


We have experimented with a lot of the above, and I like the van to handle as tightly as a big heavy van can without going hugely harsh in ride.



Our current, for several years now, variation was also a "what if" experiment. We had been running airbags and a 1 3/8" rear swaybar for quite a while, but it still would bottom harshly on the overloads on big dips in the road, which was loud and irritating. I changed the airbags to the type that have an internal urethane bump stop so the van couldn't bottom to full travel if the bag failed and then I removed the overload leaf from the springpacks. This softened the rear ride a bunch and increased the smooth travel without bottoming problem as it would now softly bottom on the internal bumper in the bags and that is silent and not harsh. I knew that removing springrate from the rear would give the van a small amount less sway control even with the good size swaybar so I upsized to a 1 1/2" swaybar to compensate for that loss. We pretty much broke even on the sway control which is still excellent and the rear smoothness got very much better, softer and more controlled.

 

[peteco]

This might sound like an odd idea, but I am wondering if adding a rear Sumospring to my heavy Roadtrek 210 might make sense. I currently have Firestone rear airbags that I am generally happy with. One concern I have is if the airbags were to fail on a long trip. Then I would be nose high due to the stiffer front springs that raised the front 2-inches.

The airbags do help a little bit on sway, but I could use more. I don't have room now for a swaybar and don't want to add the weight either.

So I would keep the airbags and add the Sumos. The airbags are handy when I am really loaded down in the back and when pulling a trailer. I also think that adding a plate on the perch for full contact with the Sumo makes sense, as it looks like Roadtreker357 perch setup will eventually damage the Sumo.

 

[booster]

This might sound like an odd idea, but I am wondering if adding a rear Sumospring to my heavy Roadtrek 210 might make sense. I currently have Firestone rear airbags that I am generally happy with. One concern I have is if the airbags were to fail on a long trip. Then I would be nose high due to the stiffer front springs that raised the front 2-inches.

The airbags do help a little bit on sway, but I could use more. I don't have room now for a swaybar and don't want to add the weight either.

So I would keep the airbags and add the Sumos. The airbags are handy when I am really loaded down in the back and when pulling a trailer. I also think that adding a plate on the perch for full contact with the Sumo makes sense, as it looks like Roadtreker357 perch setup will eventually damage the Sumo.

I am sure it will help some on sway, but as mentioned not like a bar would. The more compression you get on the Sumos in static position, the more it will help sway because it will stiffen the rear more. Balance of sway and ride. You may want to consider, if you have a way to make it, would be to make the contact plate for the Sumo adjustable, probably with shims to be able to easily change just how hard the Sumos contact the stop plate. Some sort of adjustable stop has been common in high performance cars forever on the pinion snubber stop that limits how far the pinion can move under heavy axle wrap. We would move them to very tight at the track and looser for on the street.


I think you would have room for the Roadmaster bar, but that would not do anything for the weight concern. Depending on how the bar and ends mounts, it may or may not be sprung weight. Most are unsprung as most of the weight is on the axle housing itself. In reality it would then still affect acceleration and braking, but not other weight related things that apply to sprung weight. It would also be in account for tire load, though.

 

[peteco]

Hey Roadtreker357, what Roadtrek year and model do you have? How did you arrive at the Black vs the Yellow Sumospring.