By Garth W. Cane
Most of us do not normally think about what our motorhome rides on as it travels down the road. We all know that it takes at least four wheels with tires on the ground to carry the weight, but what is between the tires and the RV that we live in? The building blocks that are essential are the tires and rims, wheel hubs, brakes, suspension system including springs, shock absorbers, axles, differentials, drive shafts, engines, and the main frame that the body rests on.
There are several companies that specialize in building the framework that supports the RV so that it gives us a comfortable and safe ride.
Most Class C or “mini-liner” bodies today are carried on a standard cut-off truck style chassis built by Ford, General Motors, or Mercedes-Benz Sprinter. This is the same style of chassis that delivery trucks use that we see on the road every day. They are designed to be able to accept loads of 9,600 to 20,000 pounds Gross Vehicle Weight Rating (GVWR). A chassis must be designed to be able to carry not only the weight of the body, but also the engine and all the things that we feel are necessary for a complete holiday on the road. Not only must the chassis be able to carry a load, but many RV’ers depend on being able to tow something behind, such as a car, boat, or motorcycle on their respective trailers.
The Ford Class C is built on the E350 and E450 Super-Duty cutaway chassis with wheelbases of 138,158, or 176 inches. These chassis support up to 14,050 lb GVWR with a Gross Combined Weight Rating (GCWR) of 20,000 lb. and are usually powered by the 7.3L V8 gas engine. The E350 and E450 chassis feature 100,000-mile tune-up intervals for the gasoline engines, with a TorqShift 6-speed transmission and tow-haul mode. The chassis has twin I-beam independent front suspension, front stabilizer bar, and gas-pressurized shock absorbers for a smooth ride. They have four-wheel anti-lock disc brakes and a steel ladder frame with six cross members. The E350 chassis has a 37-gallon fuel tank, with an optional 55-gallon fuel tank. This chassis can tow up to 10,000 pounds. Optional features include automatic emergency braking, lane departure warning, forward collision warning, post-impact braking, adaptive cruise control, distance alert and automatic high beam control.
The Ford Transit cutaway chassis comes in three wheelbases, and up to 6,400 pounds of payload capacity. It is used for smaller motorhomes. It has a gross vehicle weight rating from 9,000 to 11,000 pounds, its gross combined weight rating is up to 15,000 pounds. The Transit has a new 10-speed automatic transmission with Selectshift. Tow/Haul is included in the motorhome prep package.
The Ford Class A chassis comes with a choice of wheelbases, 158 to 252 inches with Gross Vehicle Weight Ratings of 22,000, 24000, and 26000 pounds. It is powered by the 7.3L V8 gas engine which produces 350 hp and 468 lb-ft of torque. It has a Torqshift 6-speed automatic transmission with Tow/Haul mode. It has 4-wheel disc anti-lock braking system for better braking performance. The 22,000 lb chassis has 22.5-inch tires with a heavy-duty track bar front suspension. This chassis is designed with an 81-inch front tread for stability with wide-body and slide-out style motorhomes. It has custom Bilstein monotube shock absorbers for a smooth controlled ride and can be equipped with a large 80-gallon fuel tank for extended cruising. It has available adaptive cruise control that employs both radar and camera technology.
A Rear engine diesel chassis allows builders to offer longer motorhomes 40 foot and up, with flat floor from the dash to the rear cap, underfloor storage, with as many as four slideouts. The diesel engine provides extra performance for hill climbing and towing a car than some of the gasoline powered units and improved fuel economy with longer engine life. These units are often powered by Cummins, Caterpillar, or Mercedes engines. Manufacturers who incorporate the rear engine diesel pusher technology include, Spartan (part of the Shyft Group), Roadmaster by Freightliner FCCC (part of the Daimler Group), and XCR super rail.
Spartan has been known for years as a builder of fire engines. These complex units give Spartan the experience to build chassis for motorhomes that include all the modern technology available. Every chassis is custom built for each manufacturer, so they make it unique to that brand of RV.
Freightliner Custom Chassis in Gaffney, South Carolina builds chassis for motorhomes, school buses, and shuttle buses and holds more than half the market for Class A diesel motorhome chassis making it the industry leader. Freightliner uses the ZF independent front suspension system to reduce vehicle roll and steering effort which results in a superior ride, comfort, and better handling characteristics.
Freightliner produces the XC, the SL, the S2RV, and the MC chassis. For nearly 20 years, the XC series chassis has been continuously refined to be the most innovative, most supported, and best performing chassis in the industry. As the first choice of more luxury motorhome manufacturers than any other chassis, more than 80% of all Class A diesel motorhomes ride on the XC chassis. Offering power, space, and versatility, the XC is designed for increased GVWR – up to 47,000 lbs. – plus floorplan flexibility through a variety of frame rail configurations.
Designed for high-end motorhomes, the SL is FCCC’s premium diesel RV chassis. With more options to support high-end motorhome features, plus ride and handling that make your RV driving experience comfortable and secure, the SL series chassis’ custom RV frame allows Class A luxury manufacturers to choose nearly any floorplan and coach length. Available with up to 54,000 lbs. GVWR, its proven Cummins ISX and Detroit® DD13 engines provide for superior acceleration and maximum towing capability.
The SC is designed for high-end motorhomes, the SL is FCCC’s premium diesel RV chassis. With more options to support high-end motorhome features, plus ride and handling that make your RV driving experience comfortable and secure, the SL series chassis’ custom RV frame allows Class A luxury manufacturers to choose nearly any floorplan and coach length. Available with up to 54,000 lb. GVWR, its proven Cummins ISX and Detroit® DD13 engines provide for superior acceleration and maximum towing capability.
The S2RV front-engine diesel cab chassis is our one-of-a-kind “Super-C” motor coach chassis. It’s designed and built specifically for the RV market, catering to drivers who want the power and performance of a diesel without the cockpit of a conventional Class A. Pulling from the breadth of our bus and truck expertise, the S2RV is the latest in a long line of RV-specific innovations in our growing list of custom-built, industry-leading chassis.
The MC front-engine diesel chassis offers a host of benefits over gasoline look-alikes. Drivers will appreciate its improved ride and handling over gasoline coaches, as the MC is crafted with commercial-grade components developed exclusively for motorhomes. And thanks to the power of diesel, the MC is optimized for towing and toy hauling.
REV Group builds coaches under the American Coach brand, featuring a luxury lineup that sets the bar in modern motorhome design, with a Freightliner® Custom Modular Chassis and GVWR’s from 47,000 lbs to 51,000 lbs, powered by a Cummins L9 or a Cummins X15 rear diesel.
Today, Renegade features industry-defying motor coaches, toterhomes, stacker trailers and more. The front engine P4 Freightliner Cascadia 116, with an Allison transmission and a 505-HP, 13-liter engine give you to the power and dependability you have come to love in a Renegade motorhome.
With more than 10,000 vehicles on North American roads, Prevost of St. Claire, Quebec, is a leading North American manufacturer of premium touring coaches and bus shells for high-end motorhomes and specialty conversions for entertainers. Owned by Volvo Bus Corporation, Prevost has access to the financial strength, product development capabilities, and quality manufacturing technology of the world’s second largest motorcoach and transit bus manufacturing group. Prevost Coaches are converted by many companies to be the ultimate in RVs built on a bus chassis.
In 1995 the Unicoach by Foretravel was born. This landmark unit had a bus type look, with a front entry, all the comfort amenities, a big 605 hp Cummins engine and the Allison World 6 Transmission on a Spartan K4 chassis. More than a quarter-century later, RVs of this configuration continue to be popular choices for serious touring.
Whatever chassis you prefer, it is best to be sure that it will carry your motorhome body, all of your worldly goods, and the food and supplies needed for a wonderful holiday safely down the road.