The all-new R Series chassis, designed from the ground up, offers motorhome manufacturers and their customers numerous performance options direct from the chassis builder.
By Jim Brightly
Technical Editor
December 2002
Following its successful 1999 purchase and subsequent upgrade of General Motors’ gas-powered motorhome chassis manufacturing operation, Workhorse Custom Chassis, C8291, ventured into new territory this past July by unveiling its new R Series diesel-pusher chassis to industry insiders gathered in Las Vegas, Nevada.
In an effort to provide motorhome customers with more choices and options, the new Workhorse diesel chassis will be equipped with Cummins engines in three horsepower modes. The standard engine is the 350-horsepower ISC power plant, with an optional 330-horsepower ISC engine also available. For those requiring more power, the ISL 400-horsepower engine is another option. Torque ratings for the three engines are 950 pound-feet (ISC 330-horsepower), 1,050 pound-feet (ISC 350-horsepower), and 1,200 pound-feet (ISL 400-horsepower).
The chassis also comes with two front air-ride suspension options. An I-beam suspension utilizing ArvinMeritor trailing arm technology is standard, while an ArvinMeritor RideStar independent front suspension is optional. Gabriel Ryde FX shock absorbers are used on all four corners.
Ride comfort and turning radius are affected by the different front suspension systems. While the chassis’ riding comfort might be subjective, the turning radii are not. Curb-to-curb turning radii will depend on the coach’s wheelbase, which will be available in four lengths: 208 inches, 228 inches, 242 inches, and 252 inches. However, each type of front suspension has a different cut angle. The I-beam front air suspension has a 50-degree cut, while the independent front air suspension enjoys a 55-degree wheel cut for better maneuverability.
Regardless of the front suspension chosen, the R Series chassis is available in two weight rating sizes. Standard is a 28,000-pound gross vehicle weight rating (GVWR), with a 40,000-pound gross combination weight rating (GCWR), a 10,500-pound front gross axle weight rating (GAWR), and a 17,500-pound rear GAWR. The optional chassis package features a 31,000-pound GVWR, with a 43,000-pound GCWR, a 12,000-pound front GAWR, and a 19,000-pound rear GAWR.
The Allison 3000MH six-speed automatic transmission with an overdrive gear resides just forward of the engine and is coupled to the differential via a very short driveshaft. The rear differential gear ratio in the ArvinMeritor axle is 4.63:1 with QuietRide ring and pinion gears to maintain a low sound level while on the highway.
Each R Series chassis incorporates Onan’s Coach Command power management system, albeit at various optional levels of capabilities. The Coach Command allows the motorhome owner to monitor and control various coach systems from a single location in the cockpit using touch-screen technology. The system can manage all power sources and requirements, including the air conditioners, water heater, and other appliances. It also can allow the owner to monitor tire pressure, tank levels, battery charge, fuel mileage, and trip information from the same location. Internet, GPS, and wireless communication systems also can be run through the Coach Command system, allowing the operator to manage nearly every coach function through one control. The removable touch-control screen enables the owner to have access to all system functions from up to 300 feet away from the coach. To quote Workhorse literature: “Coach Command helps to maximize reliability by monitoring systems and providing diagnostics. It puts coach, chassis, and service information at the owner’s fingertips.”
Workhorse expects to have production-line chassis delivered to manufacturers this winter, with the first completed motorhomes on the new chassis reaching dealerships late in the first quarter of 2003. So, keep your eyes open for this new player in the diesel-pusher chassis market.