Wednesday, September 27, 2023


Ask Dave: Why is there no rear engine gas pusher Class A?

Dear Dave,
I don’t know if this is your area, but will ask anyway. I see many RV reviews about Class A motorhomes being a pusher, but always with diesel. Why don’t they make a pusher with gas? Naturally this would be for smaller class A’s. Looking to upgrade. —Jeff, 2016 30-ft. Gulfstream

Dear Jeff,
There have been a few attempts at a rear engine gasoline chassis going back to FMC and Winnebago’s famous disaster, the Spectrum 2000. In 1999, Winnebago set out to engineer a state of the art motorhome similar to the GMC with a rear engine gas chassis designed and built completely by Winnebago. It was a unibody construction chassis similar to an automobile rather than a frame rail and featured the Ford 460 CID with C-6 transmission. It was a beautiful motorhome and drove like a dream. However, all 95 units were repurchased by the company as the weight of the rig was too much for the engine and drive train, and several started on fire. I picked up a repurchased unit in Bangor, Maine, and drove it back to the factory. I had never driven anything as nice before, nor have I since. You can read the press release here.

Universal Fuel Option (UFO) chassis

Fast forward several years and Workhorse Custom Chassis introduced the Universal Fuel Option (UFO) chassis for the 2008 model year that could be outfitted with a diesel or gas drive train and featured the Chevrolet Vortec engine.

The V-8 Vortec engine was a 8.1 liter gas engine with 340 hp and an Allison 2100 6-speed transmission. Only two RV manufacturers offered it, one being Winnebago on the Destination and Adventurer Limited. Here is the feature page in the 2008 Winnebago Destination brochure.

The concept sounded good on paper. However, several engineering setbacks delayed the gas offering and only a few were actually built. Then the economics of 2008 hit with the high gas prices, stock market crash, housing bubble bursting, and financial institutions failing. The RV industry pretty much shut down. Workhorse was hit hard and was eventually purchased by Navistar, if memory serves me correctly. Then in 2010, new emissions were implemented and that meant new certification for engine manufacturers. Chevrolet dropped that engine and even today we only see the Ford F53 with a gas engine. I’m not sure exactly when the UFO dropped out of the offering, but it was close to 2008.

So why not reintroduce a rear engine gas model? In my opinion, it’s price vs. performance compared to the diesel. The Ford F53 is a chassis that is used in several markets, not just the RV industry. So all engineering and production costs are shared. The cost to develop a rear engine gas pusher chassis that would most likely only be used in the RV industry would be very costly.

UFO chassis didn’t have features of diesel pushers

The UFO chassis did not have the features of the diesel pushers such as air bag suspension, 10,000 lb. towing capacity, specially designed front steering system, air brakes and other features. And the cost was too close to the diesel to justify purchasing it vs. the diesel. Most RV buyers looking at the larger Class A units not only wanted the diesel, they wanted it with 360-400 hp or more, even if they didn’t need it.

One thing I’ve learned in the RV business is never say never! So will a gas pusher become available in the future? I doubt it. I would venture to say we could see an electric pusher available instead? But then, what’s the point as the advantage of a rear engine unit is no engine noise—which is one of the advantages of the electric engine. However, with the engine in the back, even if it is electric, that means no engine in the front. So there can be a bus-style front door and no “dog house” engine cover between the driver and passenger.

Dave Solberg is a leading expert in the RV industry and the author of the “RV Handbook.”

Read more from Dave here


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Dave Solberg
Dave Solberg
Dave Solberg is a leading expert in the RV industry and author of the “RV Handbook” as well as the Managing Editor of the RV Repair Club. He has been in the RV Industry since 1983 and conducts over 15 seminars at RV shows throughout the country.


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1 year ago


1 year ago

Gas pusher would be interesting, but will probably never happen. Kinda late as far as putting R&D monies into something tried and true, and closing in on electric probably will never happen mainstream. But like the author said “never say never”. Now a hybrid gas pusher would be really a good idea IMO. Not just what most people think of a hybrid, but as a helper to get the rig rolling as well. Just a few of my thoughts on it.

1 year ago

Dave, I cannot open the link you noted for the Spectrum – CenturyLink is blocking it thru McAfee Virus site – they say it is a “botnet” whatever that is. Seems the botnet attacks all your devices – so they won’t let me access the site. I would like to see the specs and pics of the spectrum. I was not aware there was ever an attempt to build a rear engine gas! Interesting. The GMC was (or is) a wonderful machine – even to this day, with the Olds engine, front wheel drive and air suspension.

1 year ago

The Aerbus Primear built by Rexhall was also a rear gas pusher but another tragedy of the 08 economic disaster, they went belly up in 09… (could also have been powered by diesel)

1 year ago

I owned a Spectrum, some guy bought a bunch from Winnebago, repowered with a V 10, changed all the rubber gas lines (the cause of the fires) and repainted. It was a great machine, except for one tiny detail. It would not Stop! The brakes were so bad! I rear ended someone! But it did go like a bat out hell.

Bob p
1 year ago

Very good article, I never knew these existed. Back in the 80’s Coachman used a slanted nose cap presumably for aerodynamics, my parents had a 32’ no slide unit. My biggest complaint of class A’s then was all the wasted space of the front of the unit. My dad and I measured the distance from the front bumper to the back of the drivers seat, 9’7”, out of a 32’ motorhome. So they had a little more than 22’ of living space. Within 6 months he had traded it off on a 40’ 5th wheel pulled by a 3/4T Ford, which he found incapable of safely pulling that big of a trailer. Trading for a 1T Chevy dually w/454 V8, eventually trading for the 6.5 diesel that they used for 9 years of full timing until they came off the road permanently.

Tommy Molnar
1 year ago

I found this article very interesting. I never even KNEW there was a gas pusher offering – EVER. I’ll bet working in these engines was every bit as hard as working on diesel pushers with their limited space.

Bob M
1 year ago

robert has some very good points. At least Winnebago’s Spectrum 2000 had a sloped front end that probably made it aerodynamic and saved gas. Which now is important. Like I said many times todays RV manufactures are not innovative with their designs.

1 year ago

Saying that a gas pusher would only be used in rvs might be true but I bet if the chassis was available there would be other uses found for it. I would be interested in a rv that had one if they included air ride and better handling. If the coaches were the short A’s up to 35 ft I feel there would be a market. Diesel’s are expensive, maintaining is expensive, DEF is problem so that makes gas more interesting.

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