We post about many aspects of our diesel pusher motorhome, a 43-foot 2005 Newmar Mountain Aire. And we’ve certainly posted a fair amount about the Class A RV in general. But we don’t often post much about the diesel pusher chassis.
So, in this post, we thought we’d take a closer look at the two main choices – Spartan and Freightliner RV chassis.
- 1) What Is a Motorhome Chassis?
- 2) How is a Diesel Pusher Chassis Different from Other Motorhome Chassis?
- 3) Who Manufactures Diesel Pusher Chassis?
- 4) Do (Did) Some RV Manufacturers Make Their Own Custom Chassis?
Spartan vs Freightliner Chassis
- 5.1) Spartan Chassis
- 5.2) Freightliner Chassis
- 6) Freightliner vs Spartan: Which is Better?
What Is a Motorhome Chassis?
A motorhome’s chassis is essentially the skeleton of the RV – the base frame that carries all of the rest, the engine, the transmission, and the suspension components. The chassis is the entire supportive structure to which everything else that makes up a motorhome is attached.
The chassis of a motorhome (or any vehicle) is a central feature of the overall quality and safety of the RV. It not only holds everything else on the rig, but it is also critical to the handling and performance of the motorhome on the road.
How is a Diesel Pusher Chassis Different from Other Motorhome Chassis?
Class C, Super C, and Class B+ RVs are built on a cab chassis. The cab of the rig is supplied by the chassis manufacturer as part of the chassis, and the RV manufacturer builds the rig’s body on the back.
The Class B RV is developed on a van chassis and is most often a commercial van converted to an RV.
The Class A RV is the only motorhome with a cabless chassis onto which the full body is built.
A diesel pusher is a diesel-powered motorhome where the engine is in the rear (like that of a commercial bus or motorcoach) and the suspension is supported/aided by a series of air bags. This air ride suspension is what is most responsible for the smooth ride of a diesel pusher motorhome.
Although it sits squarely in the “Class A RV” category, a diesel pusher is an entirely different animal than its gas-powered Class A cousins. It also has a very different chassis.
Diesel pusher motorhomes are (generally) larger, heavier, and longer than other Class A motorhomes and often come with luxurious features such as high-end furniture and appliances. This is possible thanks to the powerful diesel pusher chassis’ gross vehicle weight rating (GVWR).
The benefits of a diesel Class A motorhome are possible due to the robust chassis, exclusively designed to support the large, long, heavy loads of diesel pushers (sometimes with tag axles).
Who Manufactures Diesel Pusher Chassis?
The two main manufacturers of diesel pusher chassis today are Freightliner and Spartan.
They’re not the only two, but chances are excellent that if you buy a diesel pusher today, its chassis will have been manufactured by one or the other of them.
There are custom RVs built on Prevost bus chassis, and Newell still custom designs and manufactures their own chassis for their luxury RVs. But, for 99% of us, our diesel pusher RV chassis are made by either Spartan or Freightliner.
In the past, companies like Monaco and Country Coach offered RVs built on their own custom chassis, because many RV owners didn’t want to own a coach that was built on a “truck chassis” like those from Spartan or Freightliner.
This notion is the result of the history of Freightliner and Spartan, both of whose main business is manufacturing chassis for trucks and other large vehicles.
However, the chassis models that are sold to RV manufacturers are not the same as those designed and used for long-haul trucks. Instead, they’re custom-designed and engineered to meet the specific demands of RV use.
Many of the components are the same, but that’s the case because those components have stood the test of time under far more rigorous conditions, specifically those imposed by the long-haul trucking industry.
Do (Did) Some RV Manufacturers Make Their Own Custom Chassis?
As we mentioned above, some RV manufacturers made (and one still offers) their own custom chassis instead of buying them from Freightliner or Spartan.
The theory behind this practice was that it gave the RV manufacturer complete control to customize & design the chassis to handle the needs and demands of their various floorplans and models. Some were more successful than others.
Let’s take a brief look at a few examples of RV manufacturers who have manufactured their own chassis to accommodate their specific RVs:
Monaco used to manufacture their own chassis, called RoadMaster (no relation to the tow bar company). On higher-end models, it used a larger number of smaller airbags, usually in pairs at each axle end, to provide a smoother ride with more responsive handling.
When the Monaco Corporation went bankrupt, they ceased the manufacture of the RoadMaster chassis. Now owned by the REV Group, the remaining Monaco Coach brand (Holiday Rambler) is built on Freightliner Custom Chassis.
This RV manufacturer is no longer in business, (though the Intellectual Property and other assets are currently owned by Winnebago). Like Monaco, Country Coach manufactured their own chassis that was said to be custom-engineered to meet the specific needs of each model and/or floorplan they produced.
Also no longer in business, Western RV was once the manufacturer of Alpine Coach diesel pusher motorhomes. They custom-manufactured their own “Peak Chassis”. It used Huck bolts to secure chassis components together (rather than welding). And their diesel pusher motorhomes were known for their heavy-duty 4-wheel hydraulic disc brakes (instead of air brakes) that provided more a “car-like” braking experience.
Tiffin continues to manufacture its own chassis called the PowerGlide Chassis. This chassis is very much like the Western RV Peak Chassis; in fact, the designer/engineer from Western RV now works for Tiffin.
This chassis, too, is Huck bolted, though the rest of the components are much more in line with current Freightliner and Spartan chassis (including air brakes).
Spartan vs Freightliner Chassis
Now let’s get back to the two main diesel pusher chassis manufacturers today and this post’s main topic, Freightliner vs Spartan.
At one time there were more differences between Freightliner and Spartan chassis than there are now. That means there are some older motorhomes that are built on versions of each chassis that had more differences between them.
Spartan was typically the choice for mid-range to higher-end makes and models of motorhomes and was offered as an upgrade for some others. Spartan was considered the choice for higher-end motorhomes due to their use of high-end components, including independent front suspension.
Freightliner chassis were more common and were most often available on a wider range of motorhomes including the less expensive, entry-level, non-luxury motorhomes.
But today there’s not a whole lot that separates the two, as the gap has narrowed significantly over the years.
While both brands offer rear-engine chassis with air suspension, let’s take a look at a few of the differences that have existed between the two top chassis manufacturers over the years.
Spartan began its foray into the RV chassis manufacturing business in 1986. In 1987, they debuted their first diesel pusher motorhome chassis.
Almost a decade later, Spartan introduced the first independent front suspension (IFS) to the motorhome market.
Most recently, in the spring of 2022, Spartan introduced a comprehensive proprietary chassis system specifically for Class A RV luxury motorhomes.
Known as Spartan Premier Drive™, the system uses custom-built high-performance shocks designed especially for motorhome use and offers improved steering control and a best-in-class advanced tag axle with a 17-degree wheel cut that enhances the turn radius and distributes weight more evenly.
The system also features an air disc brake system that decreases stopping distance and adds stopping power.
In the past, Spartan chassis offered an advantage to motorhome owners based on easy access to basic service components. Their “Service Center” feature located the most commonly changed filters outside the engine compartment, making DIY maintenance easier. Freightliner has since stepped up its game in this regard, but Spartan continues to have an edge in functionality in terms of self-service.
Spartan offered the industry’s first built-in integrated air brake system for the towed vehicle, called “Safe Haul”. An auxiliary air connection at the back of the chassis allows you to connect an airline to a (separate) air-operated tow brake system (like the Demco Air Force One or the M&G 2.0 Brake System).
Spartan also offers an advantage with a limited lifetime warranty on the frame, a 5-year/100,000-mile Cummins engine warranty, and an Allison 5-year/200,000-mile transmission warranty.
The Spartan chassis is well known for its use with high-end luxury motorcoaches and is highly regarded in the industry.
You’ll find a Spartan chassis on luxury motorhomes including the following:
- King Aire
- Mountain Aire
- London Aire
- Dutch Star
The Spartan chassis is offered as an option on Newmar’s Ventana and New Aire.
- Realm (FS6 and IH-45)
Freightliner is part of the Daimler family. Its Class A diesel offerings are based on a considerable amount of engineering expertise that has continued to improve the diesel pusher chassis over time.
According to Freightliner, more than 80% of all Class A motorhomes are built on the XC chassis in combination with a variety of Cummins diesel engines (Cummins ISB, ISC, ISL, ISM, and ISX).
The use of Freightliner’s chassis has been widespread in the motorhome industry for so long that it offers a distinct advantage in terms of support. Parts, dealers, and repair shops are available nationwide, and Freightliner’s OASIS customer service network is very large and highly respected.
Another advantage to Freightliner’s chassis has been the inclusion of a “chase” down the chassis that was made available for RV manufacturers and RV owners to run additional wires the length of the rig as needed. This feature offers a significant edge of convenience for anyone working on the rig’s electronics.
Motorhome manufacturers that use a Freightliner chassis include:
An interesting note, back in 2003 Freightliner and Winnebago joined forces to develop a chassis known as the Evolution (a name trademarked by Winnebago). Winnebago had the exclusive right to use the chassis during that model year and used it on the 2004 Winnebago Vectra and Itasca Horizon.
The chassis was a straight (formed) rail chassis, 13 inches deep. It was thicker than normal at 5/16 to provide a stiffer frame.
- Canyon Star
- Dutch Star
- Dutch Star Tag
- Kountry Star
- New Aire
- Ventana Tag
- Pace Arrow
- American Eagle
- American Dream
- American Tradition
- Sportscoach RD
- Sportscoach SRS
- Tuscany Tag
- Venetian Tag
- Allegro Bay
- Allegro Red 340
- Allegro Red 360
While not diesel pusher motorhomes, the following diesel-powered Super C RVs are also built on Freightliner chassis:
- Accolade (Freightliner S2RV)
- Accolade XL (Freightliner S2RV)
- Seneca (Freightliner S2RV)
- Seneca Prestige (Freightliner S2RV)
- Super Star (Freightliner M-2 106)
- Supreme Aire (Freightliner M-2 112)
- Valencia (Freightliner S2RV)
- Verona (Freightliner M2-106)
- Verona LE (Freightliner M2-106)
- Explorer (Freightliner Cascadia 116 single axle)
- Renegade XL (Freightliner Cascadia)
Freightliner vs Spartan: Which is Better?
The truth is that both Freightliner and Spartan make excellent chassis. Our current RV is on a Spartan (their Mountain Master GT tag axle model), and our first RV (a 2002 Fleetwood Bounder Diesel) was built on a Freightliner Custom Chassis. Both got us comfortably from point A to point B.
In the case of our Bounder, we didn’t have a chassis choice… it just came on the Freightliner. When we custom-ordered our Mountain Aire, we chose to “upgrade” to the Spartan after hearing from many owners that it was the better option. It has served us well for all these years, but we can’t honestly say that we can attribute the differences we’ve seen strictly to the chassis manufacturer.
There are many different levels of chassis available from both Spartan & Freightliner, and the RV manufacturer specs each chassis to suit the needs of the model RV being built on it. Our Bounder Diesel was an entry-level model at a lower price point (and thus, a lower-level chassis), while our Mountain Aire is most definitely a higher-end RV. Much of the improvement we’ve experienced in the ride of our Mountain Aire can be attributed to other factors: higher overall weight, larger tires, and the presence of the tag axle… all of which help to smooth the ride but makes it hard to assign that improvement strictly to the brand of chassis.
In the end, both companies are highly reputable, each has its place in the industry, and each serves its end customers very well.
For more information on the specs of various Freightliner diesel pusher chassis, see the Freightliner RV website.
For more information on the specs of each of the Spartan diesel pusher chassis, see Spartan’s RV chassis website.
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