Leveling the Load with Self-Adjusting Suspension Stabilizers
April 1, 2009
Filed under Destinations
Maxing out the rear suspension on a truck seems to be common among fifth-wheel and truck-camper owners. When the rear axle is called upon to carry enough weight to slam the gross axle weight rating (gawr) – and sometimes even overload the axle -the attitude of the truck tends to go nose-high. To put things on a more even keel, SuperSprings offers a line of what the company calls Self-Adjusting Suspension Stabilizers, designed to work in concert with the truck’s existing spring pack.
First off, let’s clear the air about the results of installing these springs: They do not increase the truck’s gross vehicle weight rating (gvwr) or tow rating; you can’t increase these legal ratings of your truck by adding extra springs, as rating increases require an expensive and complex vehicle-certification process. The best, most responsible course of action is not to overload the truck by exceeding any of the manufacturers’ weight or tow ratings, but even a truck that’s properly loaded can display an undesirable degree of tail end sag. You can improve that loaded ride control and attitude, and that’s exactly what these SuperSprings achieved.
The test truck, a 2000 Dodge Ram 3500 4WD, was heavily loaded with a Lance camper. The rear end was always squatting, even with the help of air bags inflated to near maximum capacity. Part of the problem was the missing heavy-duty auxiliary springs commonly used on trucks with an 11,000-pound gvwr. The truck was purchased new, and when confronted about the missing springs, all the service personnel could do was scratch their heads.
Installing the SuperSprings is not rocket science, but it does take strong mechanical competence and the ability to get under the truck while taking the weight off the factory springs. In this case, we asked Bill Gehr of Bill’s RV Service (805-339-0882, www.billsrv.net) in Ventura, California, to do the installation. Tools needed to complete the project are common, although having the SuperSprings Installation Tool ($100) made life much easier than compressing the springs with a large clamp.
Once the truck was situated on the lift platform, the rear wheels were raised until they were slightly off the ground, leaving the main spring pack at its most relaxed position. At this point it is critical to support the vehicle with jack stands.
The SuperSprings leaf was placed directly on top of the Dodge’s factory spring pack and bolted in position using proprietary shackles. SuperSprings are installed over the factory overloads if they are already in place. Starting at the front, the special installation tool is used to compress the added spring so that the shackle can be installed. After bolting the new shackle through the eye of the SuperSprings leaf, the bottom portion is attached using a roller that rides below the factory spring pack – part of the unique design of this system. Most of the brackets have two bolt-holes, depending on the application, with the top hole resulting in the biggest increase in ride height; we used the bottom hole since it provides the least amount of preload tension on the SuperSprings, keeping the truck closest to its stock ride characteristics. And we were using a heavy-duty version of the added springs. SuperSprings are available in light-, medium- and heavy-duty iterations and are applicable to just about any Ford, Chevrolet and Dodge truck plus many Toyota and Nissan models.
At this point it’s important to ensure there’s enough front and rear clearance to allow the rollers to move toward the axle when the truck is under load. We had to modify a few factory bolts on the frame to accommodate this requirement, but the process was no big deal.
The rollers allow the SuperSprings to react freely without being bound solidly to the stock springs as can happen with auxiliary leaf products that mount using fixed U-bolt systems. The SuperSprings’ progressive performance is due to the leaf-spring design. As the factory springs respond to various loads by flattening, the movement activates the SuperSprings through the rollers, providing the necessary support. Therefore, when the axle is not loaded or the truck is running solo, the SuperSprings do not seriously affect ride quality. However, since the springs are under a degree of preload, even unloaded, they will affect the ride quality to some nominal degree.
The other part of the equation for this application was retaining the air bags. They fit nicely on top of the SuperSprings without having to modify the top mounting brackets. All we needed were longer bolts to reinstall the bottom brackets.
Before we installed the SuperSprings, we measured the ride height in the rear using the top of the wheel opening in the bed as our reference point. With no air in the bags, the distance from the ground to the reference point was 38 9/16 inches; with 80 psi in the air bags, the measurement was 40 1/16 inches.
With the SuperSprings in place, the height without air in the bags moved up to 40 ¼ inches, which was better than the ride height with 80 psi in the air bags. Once we added 55 psi to the air bags, the ride height increased to 41 inches and at 80 psi, the height moved up to 41 ½ inches.
We were pretty happy with the attitude of the truck with 55 psi in the air bags. And the end result was very impressive: Not only did the truck look “healthier” without the sag in the rear, but ride quality improved dramatically. Reducing the air pressure in the bags helped soften the ride by allowing the springs to work as designed and travel more freely. The spring addition also limited the rocking action when negotiating driveways and making sharp, slow-speed turns.
Overall, the ride quality and “attitude adjustment” made the $450 (for the kit only – labor charges will also apply) investment in the springs worth it. And, as a side benefit, the air bags were allowed to work more efficiently as a leveling device while in camp – since near maximum inflation was no longer required just to keep the truck close to level.
SuperSprings, (866) 898-0720, www.supersprings.com.