above: visiting the Tiffin factory is always a drool-worthy experience.
If you read our last blog post, you know that we’re in the process of upgrading to a new motorhome! While our upcoming Tiffin Phaeton has DNA in common with our current Tiffin Allegro, there’s quite a lot that’s different. These differences fall into two main categories: the engine & chassis (the stuff that moves us around), and the house (the box we live in). In this article we’ll talk about the some of the engine and chassis differences.
Engine and Chassis
There are two conflicting sentiments in the RV community about diesel motorhomes. One says: “You drive your motorhome 10% of the time, and live in it (parked) 90% of the time, so don’t waste money on a diesel engine and chassis that only benefits you 10% of the time.” The other sentiment says: “Don’t test-drive a diesel motorhome unless you’re prepared to buy one.”
When shopping for our first motorhome in late 2013 we avoided any opportunities to drive a diesel pusher. We’d been told over and over that the difference is like night and day, and we’d never be satisfied with a gas rig if we’d driven a diesel. Well, we’ll soon have a chance to put that assertion to the test!
Rover is built on a Ford F53 chassis with a Ford V10 gas engine in the front. Think of him as a really long and fancy U-Haul truck! He’s never failed to get us over a mountain or across the country, but he doesn’t always do it in comfort. With the big engine roaring right in front of us it can be hard to carry on a conversation while climbing hills. With all his weight resting on springs, the ride can be bouncy and jarring. With a zero-to-sixty time measured in decades (slight exaggeration), it can be stressful merging onto busy highways. His chassis is rated for a maximum of 24,000 lbs. but he weighs almost 21,000 lbs. completely empty, so we can only carry 3,000 lbs. of “stuff” with us. That sounds like plenty until you consider that a full tank of water weighs 650 lbs., a full tank of propane weighs 80 lbs., Opie weighs 80 lbs., and Kathie and I weigh <REDACTED>! We’ve gotten weighed a few times and we’re usually close to our limit. Below we weighed in at 23,500 lbs., and that was with a mostly-empty fresh water tank:
The Phaeton is a “diesel pusher”: diesel because of the engine type, and pusher because the engine is in the rear, not the front. While most diesel motorhome chassis are made by Freightliner, ours (called a PowerGlide chassis) is custom made by Tiffin for a subset of their motorhomes. This lets them integrate the design of the house and chassis to provide a better overall solution vs. working around a 3rd party chassis design. The PowerGlide chassis provides taller and more spacious basement cargo compartments, an independent front suspension, improved electrical wiring, and more.
The Cummins L9 turbodiesel engine in our new rig will provide 1,150 ft-lbs of torque (vs. Rover’s 420 ft-lbs) for better acceleration, easier mountain climbing, and includes a significantly better Allison 3000 transmission. Air brakes and the two-stage compression brake easily keep speeds under control while descending big mountains. The air suspension is reportedly much more comfortable than springs, and with the engine in the back, it’s essentially inaudible from the cockpit. And while the diesel chassis weighs a ton more (6 tons more, actually), it can also carry a lot more weight. Our new cargo carrying capacity will be 6,000 lbs., double Rover’s. Now, whether to fill that extra capacity with 3,000 lbs. of Coke (me), fabric (Kat), or treats (Opie) remains an open question.
There are a lot of other benefits, some big (for us), some small. For example, buying fuel will be much easier now… no more checking Google satellite view for every single gas station to find one that we can fit into! With Rover’s fuel fill on the rear cap, 38′ behind the front of the rig, we’ve found plenty of gas stations that we’d not be able to fit into, or at least wouldn’t be able to get out of once we filled up (since we tow our car, we can’t back up to get out). To pull up to the pump, our nose would be through the store’s window or we’d be blocking the whole parking lot. From now on it’s the big rig diesel truck lanes at Flying J truck stops!
We expect the diesel rig to get at least 25% better fuel economy, but diesel gas is often 10-15% more expensive, and now we need to buy DEF (Diesel Exhaust Fluid) to neutralize our emissions, so we expect fuel costs to be a wash. Oh, but don’t forget the air horns – actually, that’s the only reason we’re upgrading. All shall hear our air horns and despair!
Pretty much the only disadvantage (and it’s a big one) for a diesel chassis is the cost. Apart from the much higher initial purchase price, annual maintenance will be higher as well. We’ve gotten spoiled paying $125 twice a year (i.e. $250/year) for oil and filter changes (7 quarts) and chassis lube. I’ve been told we should plan for $600-$1,000 for our annual diesel engine service, including a 24-quart oil change (gulp!) and various filter replacements. Then every few years the additional required services are even more expensive.
Coming up in our next blog post, a look at our new floor plan and some of the many improvements to the house we’ll be living in for the foreseeable future!