Airbags vs. Overload Springs: Which is Right for Your Motorhome or Truck?

Overloaded vehicles are dangerous, period. While a rig may be rated from the factory to haul a specific load, that load can—and will—drastically change the driving characteristics of said vehicle. If the vehicle is loaded heavily in the rear with a trailer or cargo, this can cause misalignment of the front end due to the suspension being unloaded and at the top of its travel. Plus the angle of the vehicle to the road is now so drastically different from the road it was originally aligned to. An unloaded front end can cause excessive or inconsistent tire wear and will most definitely reduce steering response to dangerous levels.

Another problem has to do with braking. With a sagging tow rig and trailer combo under hard braking due to the un-level combo, the trailer will push the read end of the tow truck into the ground, thus unloading the front suspension, reducing steering control and braking ability substantially (front brakes generally handle 70 percent of the vehicle's stopping power).

With a motorhome (or truck and camper), the problem can be the same but slightly different. Most motorhomes, Class A, B, or C, are loaded fairly evenly front to back from the factory. The springs fatigue as they age, causing in most cases an extremely soft/bouncy ride, excessive bottoming out, and much more body roll through the turns. The end result is less control of the vehicle, often to dangerous levels, and more stress behind the wheel.

There are multiple ways to remedy these overloaded issues: A good set of shocks will control the bounce but will not help with the overloaded and un-leveled issue. For that we need to look at airbags or overload/helper springs. Each will get the job done, but both have their pluses and minuses.

Overload Springs or Helper Springs

Overload springs, also known as helper springs, are an additional set of springs attached to the existing leaf springs. They will only work on leaf-sprung suspensions. We've seen many different designs, but the most common and the ones we have had the best luck with so far come from Hellwig Products. Hellwig's springs are available in many different strengths and are fairly adjustable from there.

They clamp to the center of the existing spring, close to the axle, and the Hellwig spring kicks in to help carry the load as the U-shaped factory spring flattens out under a load. This design allows for a decently smooth ride while unloaded. We prefer this type of load control device for vehicles carrying a load the majority of the time on the road, like a motorhome or a 100 percent dedicated tow rig. You should consider airbags if you use your tow rig as a daily driver as helper springs, despite their progressive design, will give a slightly stiffer ride when unloaded.

Airbags

Airbags are great for their quick adjustability. Unloaded, the 'bags need only a small amount of pressure (10 psi average), making for a smooth from-the-factory ride. Once loaded, the 'bags can be filled to level the vehicle and will then still offer a smooth ride. Got a few different trailers? Is your tow rig your daily driver, as well? Or maybe you tow with your motorhome only about half the time. Airbags are a perfect fit. Sure, there's a risk of air leaks or blowouts, but that risk has, for the most part, disappeared over the last decade or so. Airbag systems are now extremely reliable.

Putting Overload Springs and Airbags to the Test

For our test, we utilized a kit from Hellwig, designed to level a vehicle within its rated capacity. It's a full bolt-on kit—no holes to drill—with a quality, heavy-duty 'bag, vehicle-specific mounting brackets, plus all the hardware, air lines, and fittings needed to get the job done right.

Once the truck was on the lift, Justin Sagert from Pick-Up Parts began bolting the Hellwig springs together before taking them to the truck. Hellwig's springs are available in many different strengths to match any load.

This particular kit mounted above the springs and is held tight with …

… two U-bolts, a mounting plate, and a few nuts.

Here's where the product gets the job done. As the factory spring flattens out under load, the Hellwig overload spring counters that action, keeping the vehicle level. In this shot, the springs are adjusted for a light load.

The springs could be set up for the load once on the ground and with the camper installed. The tension or strength is adjusted by tightening or loosening the outer U-bolts. Jam nuts make sure the springs stay at the intended setting.

Our next tow rig sees many different trailers as well as cabover campers on a regular basis. Airbags were the best choice due to their ease of adjustment. Here, Matt Sizemore from Pick-Up Parts readied the truck for Hellwig's airbag kit.

After removing the factory bumpstop, the airbags were then installed to the frame first. While the 'bags themselves are fairly universal, Hellwig designs brackets to mount them with, custom for every vehicle. Most require no drilling and install using factory holes in the frame.

With the top mounts secured, Matt then bolted the lower brackets to the axle using a few U-bolts and clamps.

The previous owner of our test rig had resorted to a set of old-school air shocks. Not exactly our cup of tea. So next on the list of tow-worthy upgrades for this rig will be a set of Bilstein shocks that will complement the airbags nicely.

The last step is running the air lines. For this install, Matt ran the lines from the 'bags to the rear bumper for easy access.

Sources

• Hellwig Products: hellwigproducts.com

• Pick-Up Parts of Mission Viejo: (949) 472-0390; pickuppartsmv.com

This story was originally published April 1, 2013. Photos by Adam Blattenberg.

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