RV Chassis Features

Yes, we agree, RV Chassis Features is a lame name, but how else does one "label" the Spartan, Oshkosh, Freightliner, and other special motorhome chasses on which most diesel pusher motorhomes are now built?

All "gasser" motorhomes manufactured in the United States during the past eight years or so are built on either the Workhorse chassis (no longer associated with Chevrolet) and the Ford V-10 F53 chassis.

Prior to 1998, both the Ford F53 chassis and the Chevrolet P-30 chassis had 16" tires. Many of the larger units required tag axles to safely carry the weight of the larger motorhomes. The newer Ford and Workhorse chasses, from 1999 until about 2004, all had 19.5" tires. The 24,000 lbs. Workhorse chassis came equipped with 22.5" tires (the same general size found on most diesel pushers). When Ford came out with the new version of the F53 22,000 lbs. chassis, it also sported 22.5" tires.

The diesel pusher chasses usually are equipped with a combination of air/hydraulic brakes, whereas the "gasser" motorhomes all come equipped with hydraulic brakes—now with ABS and full 4-wheel disc brakes, rather than the pre-1998 units that often had front disc brakes but rear drum brakes.

Gas Engine vs. Diesel Engine. Gas units are cheaper to buy initially, require less expensive maintenance, but yield poor gas mileage (usually around 7 mpg for the newer coaches and less than that for most older ones), and wear out quite rapidly. Most gasoline engines in motorhomes are considered to be “very tired” when they have only about 70,000 miles on them.

In older gas motorhomes (prior to 1998), the Chevy P-30 chassis with a 454 CID V-8 engine could handle only a 16,000 lb. load, whereas the Ford F53 chassis with a 460 CID V-8 engine could handle a 17,000 lb. load. In l999 Ford came out with a totally new F53 chassis with a 6.8L V-10 engine, that came in three load ratings of 15,000, 18,000 and 20,500 lbs. A couple of years later, the Chevy Workhorse chassis with an 8.1L V-8 engine came on the market and had load ratings of 20,700 lbs., and 22,000 lbs. And then Ford also came out with a 22,000 lbs. chassis, which Workhorse followed with a 24,000 lbs. version. As you can see, the newer motorhomes have higher load carrying capacities than the older motorhomes.

Diesel units cost more to buy, yield better fuel mileage (somewhere between 10 and 14 mpg), and require more costly maintenance (some using 32 quarts of oil for an oil change), but diesel engines are much more robust—easily going more than 500,000 miles without an overhaul. Diesel motorhomes generally come on three different chasses—Oshkosh, Freightliner, and Spartan. The load carrying capacity of the diesel chassis motorhomes is anywhere from 22,000 lbs. to almost 60,000 lbs.

The three most common diesel engines in motorhomes are Detroit, Cummins, and Caterpillar. Diesel owners have very strong opinions about why their chosen engine is better—and can easily get involved in intensive disagreements.

Diesel engine coaches are usually "pushers" with the engine located in the rear of the motorhome— making the front very quiet, and conversations between driver and co-pilot are in normal speaking voices. The downside, for many RVers, is the loss of storage under the bed (taken up by the rear engine).

Until fairly recently, when someone mentioned a diesel-powered motorhome, just about all of us immediately thought of diesel pushers, which have been around for decades.

Now, however, there are two new entrants to the diesel motorhome group.

• Diesel-powered Class B motorhomes
• Front-Engine Diesel motorhomes (on a truck chassis)

Diesel-Powered Class B motorhomes. The new Sprinter chassis from Chrysler, is outfitted with a Mercedes-Benz diesel engine that is quite fuel efficient. As the popularity of this chassis increases, so does the different number of firms that are now marketing a Class B motorhome on this chassis.

Although the basic chassis and body is rather slim (looking almost too tall for its width), the RV manufacturers have begun to make some interesting changes in order to pack more RV features into the small space. Several manufacturers use only the chassis and front end— putting their own wider, fiberglass bodies on the Sprinter chassis.

FRED—Front Engine Diesel.—Although there are some folks who might argue that the Sprinter is also a front-end diesel, this term is usually used to refer to those much larger motorhomes (most often a variation on a Toy Hauler) that has been put on a Freightliner truck chassis. These motorhomes and Toy Haulers still have the Freightliner front end on them, but each manufacturer adds the rear portion in their individual ways.

Some of these RVs are quite fancy, outfitted with all the latest gadgets, and, therefore, can easily cost more than $100,000.