Warning about use of Sulastic Springs on a Solitude!

[Nuffsaid]

As to load carrying cappacity, I agree with you 100%. You want more capacity you need more leaf spring, not sumo spring. But sumos aren't installed to increase capacity, they are there to dampen the downward motion of the trailer, they have nowhere near the spring rate of the leafs. They do virtually nothing while criusing down the hwy, barely even contact, they help with bounce and sway on cross winds, bridge transitions etc. And if you drove a sumo equipped trailer through some kind of road hazard that bottomed out the leaf springs and sumos, I agree that would do some serious damage. That same road hazard, if you didn't have the sumos..... the axle still would have punched a hole the frame. Either way...frame damage.
Just FYI, my 2021 303RLS has the frame reinforced all along the frame from 2 or 3" before the front hanger all the way to 2 or 3" past the rear hanger.

As to your bushings etc...that's what I meant earlier about how poorly RV manufacturers execute the tandem suspension. The manual recommends a complete teardown of the suspension every 12 months. Because they know its garbage and doesn't last.

I really like it when rv frames have a piece of tube steel welded to the bottom flange of the frame above the spring hangers. GD did this to raise the trailer, but it adds strength to the lower flange of the I beam. With the tube steel in place there is less likelyhood of damage from having a sumo spring in place. But, on a regular I beam frame there is a severe load placed on a unreinforced section of the frame from a sumo spring when a severe compression of the srings takes place where with just the springs there the springs will deflect and should not contact the frame. I have never witnessed where a spring U bolt has contacted my frame and we have some pretty bad roads in Wyoming and Montana where I travel most. I just watched a youtube video of a guy with a GD Momentum that suffered frame damage, I think his equalizers bent severely. He had sumo springs installed and he took the trailer back to GD to have it repaired. They told him to remove the sumo springs! Think of it another way, if the spring is compressed suddenly and and the sumo spring compresses but also bottoms out, the energy has to go someplace and could actually result in the springs being pushed sideways and bend the spring hangers. RV's don't have an actual bump stop designed into the suspension like pickups do. A pickup bump stop is designed to cushion and stop the suspension on hard bumps. This is the location that after market air bags are installed and they can be ok as long as the air bag isn't supporting the bulk of the load, they should just be there to assist the factory springs, but they are in a location that is engineered to receive impacts at maximum rated capacity and not be damaged.