- Yaw also known as the ‘tail wagging the dog’ effect – This will be most pronounced in longer RV’s with a relatively short wheel base and a long rear over hang. The sensation you will feel is the rear of the RV redirecting the front of the RV left and right. With so much weight and side wall surface area past the rear axle this part of the motorhome acts as a lever against the front of the RV. As the wind from a passing vehicle hits that back corner the front immediately wants to head into that passing lane. That’s when the old pucker factor kicks in as you hold your breath, re-correct the steering multiple times, and the breathe a sigh of relief until the next truck or bus comes along. It’s not always the wind or a passing vehicle that will give you that feel, it could be as you make a fast maneuver left or right or deep ruts in the roadway causing you to go back and forth and the weight behind that axle exaggerates the movement. So what is the fix you ask? Well, often a motorhome with this issue would see the most improvement in Class C RV Ride Control with the addition of a trac bar. A trac bar attaches to the frame of the RV and the rear axle housing, eliminating any side to side movement in the rear axle, and giving you a much more solid feel. This is not the only solution, as we will discuss later, but it is one of the best solutions and the TigerTrak by Blue Ox is the perfect product to solve this problem. It is designed to easily bolt on to your specific motorhome chassis and we found it to have a “dramatic” (and I mean dramatic!) improvement in handling and control of the motorhome. I cannot stress how much I recommend this one product for Class A & C owners if your motorhome does not already have one installed. Super Steer also makes an excellent product, check out their trac bar here. A steering stabilizer will enhance this upgrade even more. You may see that you already have one from the manufacturer, but these tend to offer only a small amount of steering dampening. Two excellent replacements in this area are the Roadmaster Reflex and Blue Ox TruCenter steering stabilizer. We have used each one of these and found that both far exceed the capabilities of the factory installed unit. The Roadmaster Reflex has a return to center feature giving you a car-like steering feel, while the TruCenter is adjustable on the fly, which is nice to combat heavy cross winds or very uneven roads.
- Roll – As you have no doubt found, entering a driveway or gas station with a curb can have a violent whipping action back and forth. Hopefully everyone was seated and nothing inside the RV flew about, but I am sure you heard about it from the co-pilot. Well, having the luxury to stand up in an RV also brings with it a high center of gravity. Add that Class C RVs tend to be at the upper level of the chassis weight rating, and you have a recipe for a lot of body roll. Low speed body roll is one thing, but at highway speeds that body roll causes major handling issues. What’s supposed to limit roll is an anti-sway bar (also known as a sway bar or anti-roll bar), which all late model motorhomes have from the factory. Unfortunately, that bar is usually smaller in diameter than it should be and doesn’t offer enough torsion resistance. We added a Hellwig Sway Bar that is much larger and saw a real improvement in cornering, cross wind resistance, and driveway entry control. This is not the only solution for excessive roll, a set of Air-Lift air bags can also help with body roll although it’s not as effective.
- Pitch also known as porpoising – this chassis handling issue will be found in Class C RVs with a long rear overhang and/or in motorhomes that are heavily loaded in the rear. Pitch is the tendency for the motorhome to teeter-totter over the rear axle in an up and down motion. So as the front wheels of the motorhome hit a bump, it raises up the front end with the rear going down. As the rear wheels hit that same bump, it now plunges the front down harder than normal, resulting in a fore and aft movement called pitching. It is very important to look into distributing items inside and in storage compartments before trying to make a fix. If the rear of the motorhome is near the max load rating and the front is only at half of its rating, it will be hard to overcome the condition with aftermarket chassis components, in this case shock absorbers. A set of Bilstein or Koni brand shocks, which feature much more damping force and rebound resistance, can be the go to solution for this issue, but remember this can also cause a rougher ride depending on your setup.
In my case yaw and roll where the 2 main issues our 31′ Class C motorhome was experiencing. A quick trip to the CAT scales gave us our loaded weight front to back. If you get luck and there is room along side the scale, you can make a second pass over the scales with one side of the RV off the weigh pads. This will give you your side to side weights. We ended up being just a bit heavy on the front drivers side and moved a few items to even things out. This is also a good time to adjust tire pressures to the manufacturers recommend ratings based on the loaded weight of the RV.
For our setup an adjustment to the factory installed air bags in the way of raising them from 50 psi to the maximum 90 psi pressure, a Blue Ox Trak Bar, a Hellwig sway bar and a Roadmaster Reflex steering stabilizer turned a white knuckle drive into relaxing travels.