Leaf-Spring Suspension Upgrades
[maghub_sidebar]
Suspended Animation
Leaf-Spring Suspension Upgrades
How to improve the handling and ride comfort of most any travel trailer or fifth wheel
O

wning an RV can be overwhelming at times. Aside from the necessary upkeep of a mobile home on wheels and the frustration of not always being able to camp where you want/when you want due to the popularity of certain locations, simply moving the new-to-you rig can be alarming. Let’s face it: Until retrieving the “fun funds” from a bank account and driving away with an oversize motorhome or towing a travel trailer of fifth wheel, most RVers have never piloted anything bigger and heavier than a pickup truck or a full-size SUV.

Not surprisingly, the thought of now being responsible for negotiating suspect roads and off-camber curves behind the wheel of a package that might weigh upwards of 10 tons or more and stretch out for, in many cases, 60 or more feet is a bit mind-boggling, to say the least. And it certainly doesn’t help matters when the RV handles or rides like a buckboard.

diagram from Lippert illustrating the position of a shock absorber installation
This diagram from Lippert illustrates the position of a shock absorber installation that can substantially enhance trailer handling and ride quality.
Okay, that might be a slight exaggeration — but the fact remains, towables and gas-powered motorhomes all tend to rely on a simple leaf-spring suspension to help tempter vehicle oscillations caused by less-than-smooth roadways. Motorhomes have the added benefit of incorporating shock absorbers into the suspension system to further mitigate a rough ride, but such augmentation is rare in the travel trailer and fifth wheel segments. Ember RV came out of the gate last year with a product line that utilizes a unique trailing-arm independent suspension made by CURT, a Lippert division, and other manufacturers are slowly gravitating to it and other designs including, but for now leaf springs still rule the roost.

There’s a reason for that — three, actually. For starters, while leaf-spring suspensions have been around for many decades, their longevity is due to the simple acknowledgement that not only does the system work, but it can be easily adapted to virtually any vehicle design. And, such a system is simplicity personified: mounted fore-and aft to the RV chassis with the axles bolted either below or above the spring pack, leaf-spring suspensions are comprised of a very few easily repaired and/or replaceable components.

Lastly, it’s a relatively inexpensive system. That’s probably less a fault of the manufacturers as it is a buying public that constantly clamors for ever-more-luxuriant, residential-quality RVs…until they have to come to grips with how much such additions add to the bottom line. We want it all — but, for the most part, we don’t want to pay more for it.

Fortunately, the reliance on leaf-spring suspensions has created a cottage industry of companies offering upgrades. Most work in conjunction with the existing suspension to reduce the impact of road hazards on the vehicle, while one or two completely replace it. In all cases, though, the net result is an RV that rides smoother and handles better than its stock counterpart. That translates into less driver fatigue and less anxiety when behind the wheel. Suspension upgrades can also improve brake efficiency and life, protect not only the trailer but its cargo — and save money by reducing the possibility of damage to the trailer caused by rough roads.

The following pages outline many of the suspension upgrades available to improve the performance of a leaf-spring suspension on a trailer or motorhome. This is by no means an exhaustive guide to what’s available — it’s just intended to illustrate the various options available. In some instances, we’ve also provided overviews of the step-by-step process for installing certain systems in travel trailers, fifth wheels and even a Ford F-53-based Class A motorhome. These systems range from mild to wild, so there’s bound to be one that fits your lifestyle and your wallet.

Lippert Center Point Air-Ride RV Suspension

Lippert Center Point Air-Ride RV Suspension
As the RV industry’s largest component supplier, it’s not surprising that Lippert offers an array of suspension enhancements, from Road Armor equalizer kits and heavy-duty shock mount kits to replacement leaf springs and upgraded shackle link assemblies. Its Center Point Air-Ride RV Suspension System, however, incorporates both the improvement of a rubberized equalizer and air bags. Designed for tandem- or triple-axle trailers, the big difference with this system is the bags are mounted horizontally, to further reduce suspension sway, rather than be mounted between the spring pack and frame. This allows the axles to work together rather than oppose one another. According to a subjective evaluation by Roush Industries, the system was found to reduce frame vibration up to 96%. It’s said to be easy to install and retrofit to most double eye-leaf suspensions. store.lci1.com

Air-Lift Air Bag Systems

Air-Lift Air Bag Systems
It’s said that more than 85% of semi tractors on the road today have some kind of air-ride suspension. There’s a reason for that — air bags work. And easily the oldest company offering such systems is Air-Lift. The company offers products for a wide range of trailer applications as well as the Load Lifter 5000 and Load Lifter 5000 Ultimate for Ford F-53 and E-450 motorhome chassis (the big difference is an internal jounce bumper that prevents damage when driving with an empty air bag). Kits include two air springs, Schrader valve and hardware. Compressor systems — including Air-Lift’s new WirelessAir handheld controller, with dual-path (left and right bag inflation/deflation) control and no lines to the cab — are available separately.
airliftcompany.com

Super Springs International SuperSprings

Super Springs International SuperSprings
For owners of Class B motorhomes built on the Ford Transit, Ram Promaster and Mercedes-Benz Sprinter chassis, sometimes all a suspension really needs is a backup for heavier loads. SuperSprings are a simple bolt-on steel helper spring intended to eliminate rear-end sag and stabilize sway and body roll. Built from high-grade shot-peened steel, it included patented roller shackles on each end that allow for self-adjustment as the weight changes. The shackles have one to three holes; the higher the hole the greater the pre-load tension, allowing the SuperSprings to start higher on the spring curve rate. superspringsinternational.com
Or, You Could Replace the Entire Suspension System
While many of the products shown on these and the following pages will make a dramatic difference in how your trailer rides and reacts, there is yet another option: replace the stock leaf-spring suspension entirely. Granted, it’s not really a viable choice for an entry-level travel trailer — these swaps are not for the budget-minded traveler — but well worth considering for someone with a luxury fifth wheel.

You can, for example, jettison the stock suspension for torsion suspension axles. Dexter is one of several companies that can help make this happen; its TORFLEX system is a torsion arm suspension that’s completely self-contained within the axle tube and attaches directly to the trailer frame using brackets which are an integral part of the assembly. The TORFLEX axle provides improved suspension relative to leaf-spring axles through the arrangement of a steel torsion bar surrounded by four rubber cords encased in the axle beam — there is no metal-to-metal contact between moving parts. Dexter offers the system in progressively higher capacities, from 600-1,100-pounds to 8,000 pounds capacity. All include precision-machined steel spindles and integral cast-iron hub/drums, with different braking options available.

Dexter TORFLEX rubber torsion suspension axle
Dexter TORFLEX rubber torsion suspension axle
Timbren Axle-Less Trailer Suspension
Timbren Axle-Less Trailer Suspension
MORryde also offers an independent suspension system in 7,000- and 8,000-pound capacities that allows each wheel to respond individually to the road. Integrated rubber shear springs absorb road shock, while the suspension allows for up to 5-1/2 inches of travel. Its beam assembly is designed for maximum wheel travel, which is said to significantly smooth the trailer’s passage across rough road surfaces. The system allows for the trailer height and side-to-side to be adjusted and also allows for automotive-style toe and camber wheel alignment to better manage tire wear. Monroe hydraulic shocks are standard to the system.
MORryde independent suspension
MORryde independent suspension
Meanwhile, Timbren (timbren.com) can set you up with its Axle-Less Trailer Suspension, available in 1,200-pound to 7,000-pound capacities and choices including standard or long spindles (for wider tires) and either standard height, a 4-inch drop or a 2- or 4-inch lift. Timbren focuses on the off-grid crowd with its system and touts the absence of axles as one less component to get hung up or damaged while overlanding. The design includes a metal control arm with polyurethane bushings and two Aeon rubber springs for quiet performance. Various hub and brake options are available.
Dexter Red E-Z Flex Rubber Equalization System
Dexter Red E-Z Flex Rubber Equalization System
Dexter Axle’s name is something of a misnomer today, because the company offers a lot more than quality axles. On the suspension side, it offers Dexair Air Ride Suspension, a number of heavy-duty suspension kits and its Red E-Z Flex suspension kit, which the company said provides up to an 80% reduction in acceleration forces on the trailer frame vs. a standard equalizer. The E-Z Flex two-part equalizer incorporates a rubber bushing that gives the equalizer more damping performance, is said to be easy to install, won’t alter the ride height of the trailer and is available in 33-inch and 35-inch spacing for tandem- or triple-axle applications. dexteraxle.com

MORryde X-Factor Crossmember

MORryde X-Factor Crossmember
MORryde is an RV design powerhouse, having introduced the first trailer steps (StepAbove) to fold out and solidly connect with the ground and the nearly effortless Zero Gravity ramp door for toy haulers. For trailer leaf spring suspensions, the company offers its upgraded CRE3000 equalizer system and the SRE4000, which includes an Z-Factor Crossmember — but you also can acquire the X-Factor Crossmember separately. Available in “drop down” and “correct track” styles, the X-Factor adds lateral support to a fifth wheel or travel trailer suspension and reduces stress on the frame (up to a claimed 94% reduction at each location). The easily installed, high strength/low alloy steel product is adjustable to fit different frames and requires no welding or drilling. morryde.com

Lippert Heavy-Duty Shock Mount Kit

Lippert Heavy-Duty Shock Mount Kit
Shock absorbers don’t really “absorb” shocks, but they do a good job of dampening suspension movement while helping to limit trailer “bounce” as it reacts to road imperfections. Unfortunately, very few travel trailers and fifth wheels come so equipped — but that doesn’t prevent an owner from making this upgrade. Lippert offers heavy-duty shock mount kits for both 3-inch and 2-3/8-inch axle tubes. The bolt-on kits include everything needed to attach gas shocks to an existing trailer suspension; shocks are also available. store.lci1.com