The last thing we want you to do is to start throwing parts at your truck or RV and expect to see improvement. You need to know that specific parts have a specific role to play. Here in the SuperSteer Education Center, we want to make sure you know how to identify what is going on with your truck or RV and how to fix it.
Q: What number coil spring should I order for my P series Chevy/Workhorse?
A: SuperSteer custom matches the spring to the actual weight of the front axle. This does require that you weigh the front axle in a normal loaded condition.
Q: How do I know if my P series Chevy/Workhorse chassis is at the correct ride height?
A: With your coach loaded to it's normal weight (passengers, luggage, etc.), check the clearance between the bottom of the upper bump stop and the top of the lower rubber bump stop. It should be right in between 2 1/2 inches and 1 3/4 inches.
Q: Do I still need to use air bags with SuperSteer Coil Springs?
A: No. When we match our springs to the actual weight, the air bags are not needed.
Q: Will the ride be harsher with SuperSteer Coil Springs?
A: No. By properly matching the springs and eliminating the air bags, the ride quality will actually improve.
Q: Will SuperSteer bell cranks fit with the OE bell crank arms?
A: Yes. The taper shaft is the same size as the original.
Q: Do I have to replace both bell cranks, or can I change one at a time?
A: You can replace them one at a time. Although, we recommend changing them in pairs. Keep in mind, the wheel alignment must be checked each time a steering part is replaced.
Q: What is the difference between a SS3032-10D bell crank arm and a SS3032-8D bell crank arm?
A: The 8D and 8P arms have a slightly smaller stud size (.665 small end of taper) than the 10D & 10P arms (.725 small end of taper). The 8D & 8P arms are found on model years 1991 and earlier. The 10D & 10P arms are 1993 and up. If you have a 1992, it's best to measure because that was a transitional year, and it could be either one.
Q: How do I know if I need to replace my bell crank?
A: On the Chevy/Workhorse chassis, with the wheels on solid ground, you can have a helper rock the steering wheel back and forth (about three or four inches) while you watch the shaft move on the bell crank. If the shaft is moving side to side, and not just rotating, it should be replaced. On the passenger side, you can push and pull on the bell crank arm where the steering damper is attached, to check for side play.
On the Freightliner XC chassis, use the same procedure. Rock the steering wheel back and forth, looking for side to side movement. This next step is a little harder, and you may want your mechanic to help you out. Loosen the steering arm from the bell crank (a SS100P puller may be needed). With the arm off, try turning the bell crank shaft. If it is bound up and very tight, it should be replaced.
Q: How do I know which size SuperSteer Motion Control Unit to order for my coach?
A: The only way to know for sure is to measure the plastic airline tubing going into the top of the airbags. The sizes vary and can be different on the front and rear of the coach.The most common sizes are ¼”, 3/8”, ½”. They are available for under 30k GVW and over 30k GVW. We also have ¾” available.
Q: Why is there so much play in my steering wheel? Is there anything I can do to reduce it?
A: We call this “steering free play”. It is, probably, the number one complaint we hear from coach owners at our shop. Steering free play is when the steering wheel can be moved back in forth in your hands when the tires are not turning. In other words, there is excessive “play” in the steering wheel. It’s easy to understand why steering free play is such an issue. Many different components make up the steering action on today's motothomes. In the steering components, you have the steering wheel, coupler, two or three universal couplings, the steering gear, sector shaft splines, the pitman arm, drag link, bell crank, tie rod ends ,and the tie rod end sleeves. Generally, it is a cumulative effect, where several components contribute to excess play in the steering.
Yes. It can be reduced or even eliminated. We perform, what we call a “dry park test,” where we put the coach on a rack with an inspection bay underneath. One technician is in the cab of the coach, moving the steering wheel back and forth and looking for play in the steering shaft, steering U-joint or coupler, sometimes even the steering wheel itself. At the same time, another technician is under the coach in the inspection bay. We systematically check each component, and adjust/repair or replace parts as necessary to restore accurate steering.
Q: My coach bounces front and back after I hit a bump on the highway, and continues for a while. What causes this?
A: We call this “porpoising”. Porpoising is front to rear bounce. The front hits a bump, then the rear hits the bump, and they both bounce independently of each other. This creates an oscillating motion. If the problem is severe enough, it can feel like you’re going to pull the wheels right off the ground. The problem is more typical in shorter coaches (low 20-foot to low 30 foot). You don’t have as much trouble in the longer coaches, up to 37 foot and longer. In the longer coaches, there is more time for the bump to settle out between the front and rear wheels, reducing the effect.
Changing out your shocks, and sometimes your springs, will usually diminish the problem significantly. On some of the IFS coaches with air bags, our Motion Control Units (MCU) can help cut down on porpoising, as well.
Q: My coach seems to follow every crack in the road. What causes this?
A: We call this “rut tracking”. Some coaches are more susceptible to it than others, but usually it happens when coaches are too light in the front. If your coach suffers from rut tracking, the first thing I would suggest is to have the coach weighed to check its weight distribution. If it is off by a few hundred pounds, you may be able to solve the problem by moving heavy stored items ahead of the rear axle (as close to the front as possible). Also, if you have a motorcycle lift on the back, you may want to consider having it relocated to the front, if possible.
When a customer comes into our shop complaining of a rut tracking problem, the first thing we’ll do is conduct a Road Performance Assessment (RPA) to determine the severity of the problem. We’ll take it in, check all the steering components, and weigh it at all four corners to determine the weight distribution. If it’s way off of our benchmark, we may add weight to the front of the coach to solve the problem.
Q: When I turn the steering wheel, sometimes it doesn’t return to center. What’s wrong?
A: Typically, a too tight or improperly adjusted steering gear causes poor returnability. Over-tightening the steering sector causes the sector shaft to put too much pressure against the worm gear. This can occur when a technician attempts to remove excess play from the steering system. Also, sticking or binding components, such as a king pin, ball joint, bell crank or even the steering column can prevent the steering wheel from returning back to center after a turn.
Alignment can also be a factor. Improper caster, and to some degree, improper toe-in, can be contributing factors. To cure the problem, we’ll start at the steering wheel and work our way down, sometimes disconnecting components along the way to isolate them from the rest of the system. In this way, we can determine which component(s) are binding and take the necessary corrective action.
Q: My coach seems to move every which way when I steer the wheel back and forth. Is there any way to make it more stable?
A: Steering problems can manifest themselves in many different ways. In some instances, it isn’t even the steering system that’s to blame. One of the most common problems we address at SuperSteer is what we call “Tail Wagging the Dog”. It’s the sensation you get when the coach seems to have a mind of its own; you steer the wheel back and forth, and the rear half steers the coach.
The first coach we experienced this on was a P32 chassis. We checked the steering gear, we tried adding stiffer springs, and added a leaf on each side. It wasn’t until we discovered the bolts on the rear leaf spring pack had moved far enough, in either direction, to make contact with the adjacent spring hanger bracket. That meant the axle was moving from side to side, causing the loose sensation in the steering. Those early coaches only had 2-inch wide leaf springs, and they would flex. Plus, they had rubber bushings that would deflect, adding to the problem.
Essentially, we created our Trac Bar to solve the issue. It is basically a large Panhard bar. The Trac Bar is mounted horizontally to the frame of the coach and to the axle, creating a rigid connection that stops axle side-to-side movement. The lack of a Trac Bar, or a worn out/loose factory bar are not the only causes of Tail Wagging the Dog, but they are the most common.
Q: My coach seems to sway a lot. What can I do to reduce or eliminate this?
A: At SuperSteer, we define sway as a leaning or rocking motion. Pulling into or out of a driveway, a sudden blast of wind, a passing truck, a sharp corner, or driving over uneven road surfaces can all cause sway. Additionally, parking by the side of the road when it’s windy, or when someone steps on board, can also cause a coach to experience sway.
It’s not so much a matter of the components in the chassis being responsible for sway, but rather, the components that can be replaced or updated to help prevent it. Weak springs (leaf or coil) or a lack of anti-sway bars can contribute to excessive sway. On an air bag-equipped chassis, it can be the very act of the air entering/exiting the bags. We use anti sway bars and shock absorbers to control sway. Replacing only the shock absorbers (if they are in good condition) won’t have as great an effect. An anti-sway bar functions by pushing down on the wheel inside the turn that’s trying to lift, keeping the vehicle flat in a curve.
The bigger the anti-sway bar, the more torsional resistance it generates. When you increase the diameter of the bar 1/8-inch, for example, it creates 20-30% more torsional resistance. Although, more is not always better. Too much resistance can cause a harsh ride on some vehicles, and can create mounting and/or clearance issues.