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A heavy load in the bed or a trailer on the hitch can make the rear sag and throw off your handling. These SumoSprings Solo Custom Helper Springs add up to 1,500 lbs of support at 50-percent compression to keep your ride level and steady. They help your factory suspension carry the weight so steering, braking, and traction stay balanced when the rear end is working hard.
The springs use progressive load control so they stay soft for light loads and firm up as the weight increases. With lighter cargo they compress easily for a smooth, comfortable ride. When loaded down, they can compress by as much as 80 percent to provide solid support and help absorb bumps and vibration. You get a cushioned, controlled feel whether you’re running empty or hauling serious weight.
Each SumoSpring works independently to handle uneven loads and reduce body roll. When one side leans into a curve or gets hit by crosswind, that spring compresses while the other stays steady. The result is better balance, less sway, and a planted feel through turns or when loading is off-center.
Made from microcellular urethane that works in temperatures from -25?°F to 200?°F, these springs resist damage from oils, road salts, and UV rays. They compress vertically with minimal side expansion so they fit safely in tight spaces without rubbing other parts. Once installed there’s nothing to inflate or adjust—no air lines or fittings to worry about—just reliable, maintenance-free suspension support.
Installation is straightforward with no drilling required. The kit includes two jounce-style springs that bolt into place using existing hardware. Once mounted, they’re ready to work every time you load up, keeping your truck level and comfortable mile after mile.

Ratings & Reviews

Ben L.
7/26/2022
My wife and I loved him on our trucks

Jason J.
6/14/2021
Still as it was when installed. Does what its supposed to do. Only partially negative affect is the ride when using this truck for my daily communtes on Michigan terrible condition roads, makes for an extra firm bounce.

Pat
10/19/2021
A follow up on the sumo springs after a year of use they are a perfect solution for your trucks suspension. They greatly reduce any body sway and help level the truck I still highly recommend these springs for anyone with a truck that is hauling campers.

Pat
10/19/2021
A follow up on the sumo springs after a year of use they are a perfect solution for your trucks suspension. They greatly reduce any body sway and help level the truck I still highly recommend these springs for anyone with a truck that is hauling campers.

Rodney
11/16/2018
The Sumo Springs are still performing well. I Hauled our 29.5 5th Wheel from Upstate NY TO Florida through a major 4 State nor’easter. We have also bought a 16’ cargo trailer and hauled it to it’s full weight capacitie. The truck is still sitting high.

John D
4/18/2022
This product is great for a suspension upgrade for hauling loads on a soft spring ttuck. The fx4s rear springs are made for a soft ride. The Sumo spring turn it into a real truck and it can pull a trailer without bouncing around. Its more in between a 150 and a 250 now. Im glad I did this.

Eric O.
9/4/2020
They work well. Definitely less sag with a trailer attached.

Bryan
9/19/2023
After a year of owning these I couldnt be happier. They do a great job of eliminating bounce, sag and keep the truck much closer to level while towing and being loaded up. Much more positive feel under load. $ well spent!!

John
10/14/2022
Still no issues. They work as advertised. I am happy I installed them.
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Richard M.
6/4/2022
after a year i could buy them again. great performance and no issues.