Smoother Sailing

A blurred motorhome indicates a rough ride
Photos: Bruce W. Smith

Upgrading to Roadmaster anti-sway bars and Bilstein shocks on Ford E-350/ E-450 Class C chassis improves ride and handling, reducing driver fatigue

Unless something is going seriously awry, many motorhome owners pay little attention to the ride and handling, focusing instead on the creature comforts, looks and layout of their home on wheels. What lies beneath the coachwork is out of sight and, for the most part, out of mind. But the chassis and suspension are the only components that play a direct role in the handling, safety and overall comfort of a motorhome when it’s on the road.

Ride quality and handling have a direct impact on how everyone feels after spending several hours on the road. Each time the coach is buffeted by a gust of wind from a passing semi, sways gently from side-to-side over undulating road, shudders on uneven surfaces or leans through corners, our body automatically reacts to keep us stable in the seat. That constant flexing of muscles can be rather tiring.

Bilstein’s B6 4600 Comfort-series monotube high-pressure gas shocks and oadmaster front and rear anti-sway bar kits
Bilstein’s B6 4600 Comfort-series monotube high-pressure gas shocks [left] have been tuned (valved) specifically for the V-8/V-10 Ford E-350/E-450 cutaway chassis that Class C’s such as Lazy Daze are built upon. They are a premium upgrade for Class C OEM shock absorbers. Roadmaster has developed front and rear anti-sway bar kits [right] to replace the small OEM anti-sway bars that are found under Class C motorhomes rolling on the popular Ford E-350/E-450 V-8/V-10 chassis. The Roadmaster anti-sway bars are made from 4140 chromoly, a chromium/molybdenum steel alloy. This type of steel is considerably harder and stronger than the standard 1020 steel that is typically used in OEM RV applications. In addition, the larger diameter of the bar increases its torsional roll stiffness.
The driver is further tasked by making dozens of calculations every minute to counteract subtle movements to keep the motorhome on the right track. That subliminal thought processing is just as taxing on the body as flexing muscles. At what point during the road trip driver fatigue creeps into the picture, and to what degree, is totally dependent on how the motorhome rides and handles.

Keys to Better Handling

Two components of the suspension play a big role in how a motorhome handles: shocks and anti-sway bars. Shocks control the movement of the springs, while anti-sway bars reduce body lean or “roll.” When these parts are functioning properly and working in harmony, ride quality and handling go unnoticed by the driver and passengers — as it should be.

Case in point: We took a 2007 Lazy Daze 26.5 Class C, built on the popular Ford E-450 V-10-powered chassis, for a 90-mile test drive along the Oregon coast and over the Coast Range into the Umpqua River Valley. The 26½-foot Rear Lounge model had logged 87,000 miles and was in pristine condition.

What we observed was typical of many older Class C’s — a soft, “boaty” ride, soft-responding steering, and significant body roll while making sharp turns entering streets or taking turns, and while driving along off-camber sections of roadway. In one part of the test route, we used a digital degree app on a smartphone to measure 17 degrees of lean around a set of 35 mph “S” turns going 40 mph — and nearly constant side-to-side motion from 1-4 degrees along flat straights at 55 mph. There was also a nearly constant jitter from the rear and a small amount of porpoising after dips in the roadway.

All of those are symptoms of shocks at, or near the end of their useful life, and OEM anti-sway bars that are marginal in their ability to adequately control the high center of gravity and loaded weight of the motorhome. The owner had accepted the ride and handling as “normal.”

Control the Roll

Fortunately, the easy way to significantly improve the ride quality and handling of motorhomes based on the Ford E-450 (and E-350) Ford van chassis is to replace/upgrade the shocks and anti-sway bars with those specifically designed for such purposes.

Estimated Cost

Labor 5 hours @ $100/hour
Bilstein shocks 4 @$115 each
RSS Front Anti-sway Bar $685.71
RSS Rear Anti-sway Bar $523.44
Total $2,169.15

Roadmaster, a company that also specializes in dinghy towing products, offers replacement anti-sway bars that are specifically sized, tuned and designed for the Ford E-350/E-450 Class C applications, far surpassing the effectiveness of factory suspension components.
“What determines the effectiveness of anti-sway bars is the diameter and quality of steel,” explained Roadmaster’s David Robinson. “For every 1⁄8-inch increase in diameter, there is roughly a 30% increase in torsional (roll) resistance. Our RSS anti-sway bars are generally 3⁄8″ to ¾” larger in diameter than the OEM sway bars, which equates up to 90% more resistance to sway.” (The factory anti-sway bars beneath the test chassis measured 1 inch in front and 11⁄8 inches in the rear, while the Roadmaster replacements measured 13⁄8 inches and 11⁄2 inches, respectively.)

In addition to the increased diameter, Roadmaster manufactures its anti-sway bars out of 4140 chromoly steel, which is said to be able to handle the excessive weight of RVs while providing the anti-roll and sway resistance without fatigue or failure generally found in lesser-quality steel OEM anti-sway bars. Roadmaster says it also uses high-grade polyurethane bushings to isolate and support the bars better than the OEM rubber bushings.

The use of such quality materials makes a dramatic difference in reducing body roll. “As a rule of thumb, we usually double or triple the amount of sway resistance provided by the anti-sway bars that are fitted on the OEM Ford E-350/E-450 chassis,” said Robinson.
Using the same app, with the Roadmaster RSS anti-sway bars in place, we observed that the body roll was reduced by almost half while driving over the same 90 miles of highways. The lean in the 35 mph “S” turns, for example, dropped from 17 to 9 degrees while the Lazy Daze’s side-to-side body rocking on the open road never exceeded 3 degrees. We also observed that responsiveness to steering inputs was noticeably quicker.

Overall, upgrading the anti-sway bars gave the test unit a more stable, refined, comfortable feel behind the wheel and extended the comfort to the person sitting in the passenger seat.

Shock Therapy

To address the Lazy Daze’s worn-out OEM rear shocks, we turned to Bilstein high-pressure gas shocks that are tuned specifically for Class C Ford E-350/E-450 motorhome applications. Bilstein engineers spent a lot of real-world seat time with fully loaded Class C’s to get the high-pressure, gas-charged, single-tube performance shocks properly tuned for a fully laden RV chassis.

Sources

Bilstein

Henderson’s Line-Up
541-479-2882

Mobile Diesel Service
541-459-8939

Roadmaster Inc
800-669-9690

The Lazy Daze was fitted with Bilstein B6 4600 Performance Series shocks (part No. 33-176840) in the rear, which the company claims are the same shock used under NASCAR Super Trucks. In addition to the vehicle-specific internal valving, the B6 4600 is a monotube design that eliminates aeration to maintain effectiveness during long hours on the road. (Aeration causes a shock to lose its damping ability and go “soft”).

While replacing the rear shocks is a piece of cake, gaining access to the top nut holding the front OEM shocks is a different matter. The driver-side body-to-frame space is very tight, so a ratchet and socket can’t be used. But the tech took it in stride, slipping in a set of companion B6’s (No. 33-187563) to replace the tired Ford gas shocks (part No.
1024-18045-AA). The new Bilsteins are covered under a limited lifetime warranty, so once they are in, they shouldn’t need attention for another 100,000 miles.

Replacing the OEM anti-sway bars and shocks greatly improves the handling of any motorhome built on the two-wheel-drive Ford E-350/E-450 cutaway I-beam chassis. Upgrading the OEM parts to those of higher quality and effectiveness reduces driver fatigue, diminishes body roll, makes overall handling more responsive and results in an overall smoother ride for everyone on board. In general terms, the upgrades make the drive safer and more enjoyable.

Whether you do it yourself, or have these suspension upgrades done by pros, it’s time and money well spent, especially if you plan on driving your Ford E-450 Class C on extended trips.


Roadmaster RSSC Steering Upgrade

There’s another upgrade to consider for improved ride and handling: replacing the OEM steering damper with one designed to actually assist steering when encountering strong crosswinds, off-camber roads, pavement ruts or even while the motorhome is experiencing a tire blow-out. Roadmaster’s Reflex Steering Stabilizer (RSSC) is designed to do just that, further reducing driver fatigue.

The RSSC ($275) concept is simple. The hydraulic shock damps rapid steering movements induced by the front tires being inadvertently pushed one way or another by road irregularities or the wind, while the coil spring surrounding it assists in keeping the steering centered by pushing or pulling the tie-rod back to its neutral/center position.

The RSSC is quite handy when the driver is steering against the effects of strong, constant sidewinds, driving secondary roads with a lot of crown or driving on sections of highway where big rigs have rutted the lane.

With the RBK mounting bracket (sold separately; $103), the RSSC is a simple bolt-on replacement for the standard steering stabilizer. The only change from the OEM setup is replacing the factory steering stabilizer bracket on the passenger-side of the Ford E-350/E-450 chassis with Roadmaster’s heavier-duty version.

Swapping out the standard steering stabilizer for an RSS unit is simple. It took us less than 45 minutes with a ratcheting metric wrench and socket set.


Stability Plus

Adding a track bar, also known as a panhard rod, is another highly effective accessory that can help reduce motorhome aft-end sway. Henderson’s Line-Up offers the SuperSteer  SS450 Trac Bar for the E-450. The bar mounts between the chassis and the axle, and allows the axle to move freely vertically, preventing sideways shift, which can happen with a leaf spring and solid axle suspension. Motorhome aft-end tail wagging due to lane changes, crosswinds and passing trucks is significantly reduced by a track bar. MSRP: $584.


 

 

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