SumoSprings Rebel: Bumpy Road Equalizer

Front SumoSprings (left) have a one-piece design. Springs are made of proprietary (and patented) microcellular urethane and are maintenance-free. The springs can compress up to 80 percent of the original height and will rebound fully. Two-piece configuration of the rear SumoSprings (right) allows for unlimited travel, a more progressive spring rate and better damping abilities. The blue kit used for the Ram test trucks is the most popular for towing trailers.
Front SumoSprings (left) have a one-piece design. Springs are made of proprietary (and patented) microcellular urethane and are maintenance-free. The springs can compress up to 80 percent of the original height and will rebound fully. Two-piece configuration of the rear SumoSprings (right) allows for unlimited travel, a more progressive spring rate and better damping abilities. The blue kit used for the Ram test trucks is the most popular for towing trailers.
photos by Bob Livingston

Microcellular-urethane SumoSprings smooth out the ride, level the attitude and enhance the towing experience

Towing with a heavy-duty pickup can be a beautiful thing, especially if trailer weight and size are at the top end of the scale. But the ride solo can rattle teeth and shake that beer belly to pieces. The harsh ride is courtesy of stiff, heavy spring packs that are needed to carry the weight and keep the truck on an even keel when hitched to the trailer. Even with the hefty springs, weight carried over the rear axle can sometimes create a racked attitude with the nose high enough to impact handling and headlight aiming.

Air springs (bags) are often called in to level the rear of the truck and provide a dose of stability. In too many cases, owners rely on the air springs to boost capacity, which is not an acceptable practice. Gross axle weight rating cannot be increased by adding auxiliary equipment. SuperSprings specializes in aftermarket suspension enhancements, and its SumoSprings Rebel product is a fresh paradigm when it comes to improving ride quality and providing additional support to control the load, especially when towing heavy fifth-wheels.

While traditional air springs do a credible job of lifting a sagging rear end, they require a source of compressed air and are far from maintenance-free. SumoSprings also use air but captured in a proprietary, patented microcellular urethane that can compress up to 80 percent of its original height and rebound fully. Once they are in place, the owner has no service requirements, and failure is just about impossible since the springs cannot leak or rupture.

The SumoSprings provide a progressive rate of damping. They are manufactured in various heights, diameters and densities for applicability for most trucks, front and rear. The urethane cells simply replace the factory bump stops, used to prevent the stock springs from slamming against the frame when traveling over rough roads.

Two color-coded spring kits under the Rebel banner are appropriate for trailer and camper owners: blue and black (-40 and -47 designations, respectively). Determining which kit will work best is based on weight and constant or variable load. The blue kit works best for owners pulling a fifth-wheel or trailer with a heavy hitch weight on a normal trip basis; this is considered a variable load. Carrying a lightweight camper will qualify for the blue kit. The black kit is reserved for those pulling heavy fifth-wheels or carrying a camper constantly (i.e., full time). According to SuperSprings, the majority of trucks pulling trailers are best suited for the blue kit. Sumo-Springs kits are also available for vans, SUVs and motorhomes.

That gave us food for thought when we decided to test the SumoSprings. Two Ram 4×4 duallies, 2016 and 2017 model years, used to tow fifth-wheels full time were earmarked for installations. Under the parameters provided by the company, it made the most sense to opt for the black kit. But, the trucks exhibited a harsh ride when driven solo, again, a product of heavy springs, and we wanted to reach a happy medium when it comes to towing comfort and driving unhitched. We decided to go with the blue kit for both trucks.

The installation is about as simple as a project can get. In the back, the SSF-301-40-2 Rebel kit has a two-piece configuration. Separate male and female sections are mounted to the axle and frame using simple hardware that’s relatively easy to install. The two-piece design allows for unlimited travel, since spring movement in the rear can be quite dramatic on rougher roads.

Once the truck is parked on a level surface and the wheels chocked, the rear is jacked up to allow the axle to hang freely. After stabilizing with properly rated jack stands, the factory jounce bumpers are removed from the underside of the frame; the rear wheels can be removed for better access, but we didn’t find that necessary. From here it was just a matter of bolting the brackets in place, a process that took about 30 minutes for both sides.

The procedure is similar for the front, but removing the jounce bumpers might take a little more convincing using a large flat-blade screwdriver and a twisting motion by hand. It might require lowering the axle to seat the SumoSprings (part number SSF-302-40-2), which have a one-piece configuration for the front. Timing for the front install was about the same as the rear.

Both trucks were tested extensively pulling the fifth-wheels and while running solo. The 2017 Ram pulling a 17,000-pound fifth-wheel had a 3,800-pound hitch weight, which sacked the factory rear springs. With the Sumo-Springs in place, the front-high attitude was mitigated enough to almost level the truck; load capacity was not an issue, so the SumoSprings had no impact on the weight rating of the axle. Handling with the fifth-wheel attached improved by at least 50 percent, with a noticeable curtailment of wallowing on some roads.

The other truck was not as heavily encumbered, towing a lighter fifth-wheel with a 2,400-pound hitch weight. Traveling rough roads made it uncomfortable for the passengers in the truck; the influence on the fifth-wheel was a separate story. The truck’s stiff stock springs caused a hammering effect inside the cab that kept the passengers in constant motion. Back-to-back tests on terribly maintained roadways were very telling. With the SumoSprings in place, the bumpiness was squelched enough to take the edge off the harshness of the ride, making it more comfortable for the passengers. Chucking was not a major issue for either truck, except on certain roads where the SumoSprings reduced the intensity of the pushing and pulling movement.

Solo, the SumoSprings really shined. The trucks became much more civilized, especially when negotiating dips in the road. On one test turn, the undulating road rocked the truck violently, throwing the passengers to the side. With the SumoSprings in place, the improvement was so dramatic, it was hard to believe we were traveling in a one-ton dually.
Overall comfort on the roadways was improved to the point where it actually made it fun to run around in a dually truck.

While we were hoping that the new springs would take the edge off travel on concrete highways with expansion joints, there was no improvement in the ride. It’s a phenomenon that seems to have no fix among the towing community.

What makes the improvement in ride quality so intriguing is that it can be done for $616 in parts ($442.50 and $173.75 for the rear and front, respectively) and about an hour’s labor for most well-established do-it-yourselfers.

SuperSprings International, Inc. | 800-898-0705 | www.supersprings.com


 

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