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Home , Axle, Panhard rod

ROADMASTER SUSPENSION & (Pre-2015) Presented by Mike Hughes

(owner of MonacoWatts LLC) Good Morning Fellow Coach Owners.

 I am here to discuss the Roadmaster Chassis and the design issues surrounding its driving and handling characteristics.

 I will cover a broad base of information and present you with proven cures for the issues involved with the RR8, and RR10 Roadmaster Chassis. (Pre 2015)

 This is NOT a ride seminar. Ride and Handling are two VERY different subjects when it comes to the Roadmaster Chassis. The Roadmaster Chassis

A chassis that was designed for inner city use by the Chrysler Corporation and purchased by Monaco for use in their motorhomes. We believe the chassis was not thoroughly tested on the highway before Monaco began motorhome production. Does your coach wander ?

Do you see-saw the ?

Is your driving experience stressful ?

Do construction zones make you sweat ?

Does the wind, ruts, and passing “push” your coach around ? Roadmaster Chassis

Would you like to know why your coach is doing what it is doing ? RR8 & RR10 Chassis

Front and Rear H-Frame movement.

Understanding how the Raised Rail (RR) coach frame, H-Frame, Panhard Bar, Trailing Arms, and operate together. The H-Frame Sub Assembly

When your Roadmaster chassis equipped coach wanders from one side of your lane to the other constantly on a smooth, straight highway, it does so because the “sub-assembly”, referred to as the “H- frame”, and to which both your front and rear are mounted, IS MOVING AND CHANGING DIRECTION, EVEN WHEN YOUR WHEEL IS HELD MOTIONLESS. The basic design of the chassis is flawed. The “H-frame” to which your front (and rear) axles are mounted, is attached to your COACH frame by four “trailing arms” which run fore-and-aft, and one Panhard bar which runs crossways of your coach. The purpose of the is to stabilize the H-frame, and prevent it from moving side-to-side. Without the Panhard rod, the relatively spindly trailing arms could easily be pushed from side to side by any external force, such as road ruts or winds. Without the Panhard rod, your coach’s could easily extend out past your wheel wells when acted on by any side force. Unfortunately, due to the natural “give” in the bushings at the ends of the trailing arms, and the relatively spindly nature of the trailing arms themselves, one Panhard rod only ensures that the H-frame cannot make a HUGE movement, and cause the wheels to extend past the wheel wells. Although the H-frame cannot make a large movement side-to-side, it can still TWIST under your coach. This twisting is responsible for your coach’s instability even on smooth, straight roads. To have your coach track straight, we need something to prevent this twisting. WATTS LINKAGE (Watts Link) Watt's linkage (also known as "parallel linkage") is a type of mechanical linkage invented by James Watt (19 January 1736 – 25 August 1819) in which the central moving point of the linkage is constrained to travel on an approximation to a straight line. It was described in Watt's patent specification of 1784 for the Watt steam engine. It is also used in automobile suspensions, allowing the axle of a to travel vertically while preventing sideways motion. -WikiPedia

"The watts system consists of two horizontal rods of equal length mounted at each side of the chassis or axle. In between these two rods, a short vertical bar (bell ) is connected. The center of this bell crank – the point which is constrained in a straight line motion - is mounted to the center of the axle or coach framework (inverted). All pivoting points are free to rotate in a vertical plane." -WikiPedia What does a “Watts Link” do ?

The addition of the Watts Linkage on the front and rear (if available) stops H-Frame movement. The center of the axle is held in perfect alignment while the vehicle moves up and down. Holding the axle dead center in the coach stops the wandering. It's an amazing change in driving. No longer are you exhausted after driving just a few hours. Our users report trips from 6, 8 and 10 hours without the fatigue. The coach will experience GREATLY reduced as it will track around a corner almost flat. Watts Link in Action 2014 Watts Link “Party” (Test Coaches)

Watts Links Fabricated and Installed. Front Hydraulic Jack Mount Watts Link Prototype (Installed 5+ years and 40,000+ Miles ago) Rear Watts Link (2011 Monaco Knight) Trailing Arms

Rear Trailing Arm deflection affects the heavy end of the coach and causes movement about the axle.

Tag Axle coaches are designed slightly different, but can still be affected by Trailing Arm deflection. Rear Cross Bars (Used to eliminate rear trailing arm deflection ) So what are Cross Bars ? Why do I need both the Watts Link and the Cross Bars?

The rear suspension on the RR8 & RR10 chassis uses trailing arms to position the axle fore and aft under the coach. These trailing arms are made of 2" x 2" tubing and are more than 6' in length. Given the long length, the trailing arms actually deflect when side forces are applied to the coach (such as broadside winds or passing trucks). You can add to this the movement from the 10 rubber bushings used in the arms and panhard bar. This deflection is small but more than enough to make the rear of the coach wander constantly. Triangulating these trailing arms with Cross Bars (sometimes called Diagonal Track Bars) holds them in perfect alignment while still allowing proper motion of the axle. “Testimonials”

Installed the rear cross bar an the front watts on are 2007 Monaco knight lot of different in the handling now . This coach was a handful until now.

Just drove the Coach again for the second time after installing the Front & Rear Watts Linkage and the additional cross bars on the Rear. It was like driving a brand new rig. Probably drove better than when it was new. Can't wait for our next big trip! “Testimonials” Once again, sure do want to thank everyone for a great time at Quartzsite. Especially want to give a special thanks to Mike Hughes. That Watts Link is incredible. I have never enjoyed driving my coach as much as I did getting back here. Even in the wind, no sway or movement. Even as trucks would go by, no sway or push. Thanks again Mike. Recommend to everyone thinking about it. Just do it!!!

The front watts continues to make driving the beast a pleasure, compared to without it. Thanks Mike and to everyone for their willingness to solve this problem! I look forward very much to adding the rear watts and cross links next month. Monaco Watts You now know there is a fix and not just a band aid for the REAL chassis issues.

Watts Links and Cross Bars manufactured as bolt on kits.

MonacoWatts.com