Diesel vs. Gas, Sanity Check

My wife and I are considering making an offer on a DP in the next couple of days and now, after looking at the price difference between gas and diesel, I am having second thoughts about diesel. Regular gas is running $3.21 and diesel at $3.89 here. That is a huge difference and I'm wondering if I should be looking of a gas powered unit instead of diesel.

The unit I am considering placing an offer on is a 40ft Tiffin with a Cummins 360. We plan to own it for about 5 years and tour the US and Canada coast to coast, towing a CR-V. The 40 foot length is at the max of our preferred size and since its just the two of us, I could drop down to about a 35-36 ft unit if gas powered.

Comments on the "Pros" and "Cons" of getting a diesel unit would be appreciated.

When I purchased our previous motor home a 2010 Fleetwood Bounder 33U with the 362 HP V10 Ford engine, I thought long and hard about how much use I was planning on getting out of the coach. The gas unit was far less expensive to purchase, and coupled with the fuel prices I didn't think long about a DP. We are weekend warriors at best, and so even out West and towing a Jeep gas made more sense.

If I were a full timer, and or even a part-timer (6-months a year of use) I would opt for a diesel engine.

I can't compare fuel usage between a gas and a diesel in that size range, but when I bought my 24' ERA, the increase in MPG far offset the cost difference between gasoline and diesel.  I was getting about 8 MPG in gas with my 32' class C (Ford V10) and went to about 18 MPG in diesel.  Since we are touring types (not campers, per se) and drive a lot, the difference in fuel costs boosted our travel budget a lot.  In that light, I suggest you try to determine MPG of the two units then make your decision based on cost per mile, not cost per gallon.

Fuel economy is only one part of the equation.  While i am not a proponent of motor homes, i think in large coaches diesel is the only way to go. Look at it this way, your 35 foot V10 gas MH pulling a toad might see 6-8 MPG on good days in mid America.  3-6 towing in the mountains of the far west.  That 40 footer, with 40SqFt more living space and diesel powered will get you around 8-9 almost anywhere you travel.  While not a big difference, again you are not comparing apples to apples, so you have to take the numbers with a grain of salt.  At the end of the year you have to decide for yourself what is more comfortable to drive, live in and maintain during your five year plan.  Have you ever owned an RV before?  If this is your first, then maybe you need to sit down have a reality check on total cost of ownership for both, total expenses per month and decide if this is really a good long term plan or not. 

Wife and I own a diesel Super C 40' that we had built for our business. It has a Cat C-11 engine mated to a 'smartshift' 10spd automated transmission. In the last 6.5 years we have been fulltime and have put 800,000+ miles on the unit. The yearly operating cost has been $51-$63,000 and that includes: fuel, maintenance, tires & insurance for commercial use. A diesel was a must. As we are approaching retirement, we are now looking for a gas powered unit in the 32-38' range and plan to average less than 15,000 miles per year. I know for many it is just like the Chevy vs Ford debate, but with the California CARB agenda and the still problematic CARB compliant diesel engines, the gas units have a more attractive appeal to us.

It is not a question of gas vs diesel, it is a question of the right tool for the right job. If you are going to be towing and if you live in the west then a diesel is your only real option. Otherwise a gasser will do just fine.

Purchase price difference and fuel mileage is only a couple of things to think about. The diesel coach is way more expensive to maintain. Oil and all the filters alone can run several hundred dollars.

Take a look at the RV park and see what the experienced folks who full time or snowbird drive. I'm looking down a row of mostly snowbirders in AZ right now and there isn't a gasser in sight. Now maybe it's not having a hot screamer next to you everytime you drive it. Or maybe its the power to crest the hill. Or maybe it's something else entirely. I'm sure it's not because an oil change costs $200. (my last was $205 with 34 quarts, filter, fuel filters) There must be something that makes old retired folks living on fixed incomes buy diesel pushers.

That's not to say there aren't full timers in gassers, there are. But, they are the minority not the majority.

It's kind of like fishing, if you're not sure of what color lure to use, or what type of hook to buy, look at the people catching the kind of fish you want to catch and see what they use. Look at the posters on this forum and read their posts. When you see a few folks that are doing the things you are wanting to do, look at their sig lines and see what they have. Then your answer will be clear.

Ken

If you are a snowbird and moving from the north to the south and back once a year and just parking in one spot but not traveling all over then gas makes more sense.  If you are a full timer or a snowbird traveling all over the place then consider diesel.

We looked at the total value of the experience, the amount of time we would be on the road (we are full time) and the places we expected to be (the West), and the amount of living space we needed, and have been in a DP since Day One. We even budgeted for $5.00 diesel.

At $5.00 a quart times 24 quarts of oil, cheap oil changes are not something you look for in a diesel. Filters are not so much obnoxious as plentiful, especially when you have an oil filter on the generator and the engine, fuel filter on the generator, and two on the engine, all getting changed at the same time. But once a year. Figure a little more than a dollar a day.

But like Ken said, the folks that drive a lot of miles over a lot of time typically tend toward the convenience and ride of a DP. And then there's the noise levels.

I regret that I am so biased, but your kind of travel pretty much screams a DP and the one you are looking is pretty much prized by most who know their rigs. I don't think you will be sorry if you can make the deal you want.

Kim

I recently test drove a Tiffin 37AB with the Cummins 450 engine in it.  The coach is very impressive and if you are going to be in the West the added HP is a plus.

How many tractor trailers do you see on the road being powered by gas?  There must be a good reason for it. I believe it's because oft  the fuel mileage and power.

We've owned three motorhomes over the past 19 years. The first two were gas powered and our latest is a diesel pusher. All things being equal, which they rarely are, diesel MHs are going to cost more to buy, maintain and operate but, for what it's worth, the difference isn't breaking the bank.

We live just outside San Diego so basically, we're climbing 6% grades anytime we head east out of town to go camping. Our last gas MH, a 1999, 32 foot Tiffin Class A with a Ford V-10, had no problem maintaining 45-50 mph up those grades (not towing anything). It was, however, fairly noisy up front while doing so, because the engine is right next to you. Having said that, I wouldn't buy a MH based on its ability to climb mountain grades at freeway speeds. The truth is, our 450 HP diesel-pusher isn't much better, it's just pushing a lot more weight up the hill.

We intend to use our current MH for more than just family vacations and weekend camping trips, which is why we bought a larger diesel-pusher.  We're going to be traveling longer distances and for longer periods of time, so comfort, both while traveling and while camping, became a higher priority for us than it was with our two previous coaches. Our DP is much quieter up front than our previous gas coaches were, primarily because the engine is 40 feet behind us, but also because most DP motorhomes ride on air bags, which not only helps quiet the ride, but REALLY smooths it out. When we were shopping for motorhomes, I did notice that motorhome manufacturers have made significant progress in quieting their gas powered coaches but none were as quiet or as smooth as the DPs we drove.

Yes, diesel fuel is usually more expensive than gasoline (you ought to see San Diego fuel prices if you think yours are high), and I'm not minimizing the affects of fuel prices on RVing. There are many, many factors to consider when selecting which RV would best suit your needs and fuel prices and mileage are some of them. It comes down to, what factors are important to you and your family, and how much are you willing to pay for them.

Kev

We've had five motorhomes in about 35 years with the first three being gas Class Cs and the last two being diesel Class As.  All had good engines in terms of load, e.g. none were overloaded.  As we were driving (crawling?) over Eisenhower Pass (I-70 at 11,000 feet elevation) in Colorado in our third gas Class C, Jerry announced that we were going to get a diesel pusher.  The first was a 34' DP with a 350 hp engine.  The current one is a 40' DP with a 500 hp engine.  We've loved them all, but the diesel sure is nice if you can afford it.

What's really most important is how comfortable the motorhome is for what you want to do.  You want to travel a lot and that means you'll want enough power for long grades in the west.  You want to live in it for long periods at a time and that means you'll want a floor plan that is comfortable for long-term living.  Remember that the weather isn't always perfect and you'll want space enough to be comfortable if you're cooped up inside for a week.  You'll want enough storage for all the required "stuff" like food and clothing and for the other "stuff" like for hobbies, paperwork, or whatever.  And don't forget, if you travel with a furry friend you'll need enough room for his/her toys, bed and food.  Most of our trips are at least several weeks in length and up to four or five months depending on where we're going and what we'll be doing.

I wonder why you plan on keeping the motorhome five years and then what?  You may be surprised at this but in 35 years we still haven't seen everything there is to see in this great country of ours.  My advice is to get a motorhome you want and don't fixate so much on the cost of gas which has been all over the map since we started RVing in 1972.  The year we went to Newfoundland was the highest it had ever been but there's no way we would have cancelled that trip.  The following year it was even higher but our friends still went on their planned trip to Newfoundland.  We all felt the same way.  The cost of fuel was nothing in comparison to the fun and memories we would have there.  By the way, you won't be traveling every single day.  There will be times when you just want to lay low and catch up with things you need to do.  That's when you'll really appreciate having the motorhome you want instead of wishing you had made a different choice.

ArdraF

dan680fl said:

Wife and I own a diesel Super C 40' that we had built for our business. It has a Cat C-11 engine mated to a 'smartshift' 10spd automated transmission. In the last 6.5 years we have been fulltime and have put 800,000+ miles on the unit. The yearly operating cost has been $51-$63,000 and that includes: fuel, maintenance, tires & insurance for commercial use. A diesel was a must. As we are approaching retirement, we are now looking for a gas powered unit in the 32-38' range and plan to average less than 15,000 miles per year. I know for many it is just like the Chevy vs Ford debate, but with the California CARB agenda and the still problematic CARB compliant diesel engines, the gas units have a more attractive appeal to us.

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My understanding is that the CARB rules have a specific exemption for diesel-powered motorhomes; they sure did the last time I read them.

True for now if you don't use your MH for commercial purposes...mine is for business and has a DOT on the side and I am subject to these regulations. In the year+ that I have been receiving CARBs update e-mails, the only thing for sure is they seem to vacillate on their proposals, exemptions, and time for compliance. I hope they continue to exclude MHs recreational use....

Current diesel prices around our area is about $3.99.  Trip last weekend to upstate New York as high as $4.55.  I can see how some steer to the gas models of TV's and MH's, however looking end to end, I prefer the diesel for the power and durability factors, now with current setup and possibly with future MH possibility.  Just our perspective.

Just ran a couple of quick numbers and with a gas engine getting 8 MPG you would spend $401.25 per 1000 miles.
with a diesel engine getting 10 MPG you would spend $389.00. I wouldn't take too many 1K trips to make up for the extra cost of maintenance.

Wizard46 said:

Purchase price difference and fuel mileage is only a couple of things to think about. The diesel coach is way more expensive to maintain. Oil and all the filters alone can run several hundred dollars.

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This kind of statement gets repeated over and over by people who don't own diesels.  Yes, the annual oil change is more expensive due to the amount of oil.  But this is an annual expense and the filters that are replaced (oil and fuel) are no more expensive than they are for a gas MH.  IMHO if an extra $200 once a year is enough to keep you from owning a DP then your budget is too tight.  Every year we also have another ~$200-400 in maintenance on items that are on 3-5 year maintenance schedules, but even a gas-powered coach will have these.  It is also worth noting that I maintain mine "to the book" and some people might decide they could reduce my maintenance costs.

As for other maintenance, roughly >80% of our repairs over the 3 years we have been full-timing have not been related to the engine, transmission or even the chassis.  They have been related to slides, appliances, leveling systems, etc, that are RV systems and are fairly common to most large MHs, gas or diesel.  Sure, diesel coaches usually have more "stuff" on them so there is more to break, but that has nothing to do with the fact that it's a DP.

Threads such as this quickly become "Ford vs Chevy" rants, but the difference between diesels and gassers can be discussed with facts, not emotion.  The bottom line is that DPs are a bit more expensive to maintain, but that difference is probably no more than ~$1k/year plus a higher purchase price.  For "weekend" RVers this may be too much, which is understandable if your usage is moderate.  For full-timers, this is a small price to pay for the comfort  and driving performance of a DP. 

But it should also be understood that not all DPs are created equal.  Even though your speed up a mountain is dependent on HP, there is a world of difference between driving a large-block, high torque diesel and a small block, low torque engine with equivalent HP. The big engine turns at low RPM and hardly notices the hills, while the small engine downshifts and turns fast to make it up the hill.  One is not better than the other, but the big block makes driving a quiet, serene experience.

Thanks for the feedback everyone.

When I initially considered the gas vs diesel issue earlier, I felt diesel was right for us but now that it's getting close to the "no turning back point" I was starting to second guess myself. We don't plan to full-time, but close, spending about 3 months on the road and 3 months off.

Now, the big decision we have to make is, do we make an offer on this unit???