Those of you who have or had a diesel Super C, what are the pros and cons of that class compared to a gas or diesel Class A?

I have not owned one, but I have shopped them, and spent many (maybe thousands) of hours behind the wheel of most of the Class-5 offerings (Ford, Dodge, GMC, Freight-liner). Here's some of my observations:Pros of a Class-5 Super-C-Generally better engine noise reduction, except the Newmar Canyon Star I test drove was pretty good too. The GMC isn't great in that regard, but it hasn't been built in a long time anyways. I'm assuming you are shopping new. The Dodge 5500 is not as well sound insulated as their pickup counterparts but its good enough.-Traditional overhead cab. The nicer Class As skip on the drop down bed (like the Newmar). The Class A's with a drop-down bed seem to be not very well put together (THOR).-Service *should* be easier. At least the cab will be common with other trucks. However, you still run into the same limited dealer network as Class As do.-More towing capacity. The Super Cs (except the GMC) can all handle 10,000 pounds vs 5,000 or 7,500 on the gas Class As.Cons:-The cab is too low. This one was pretty much a deal-breaker for me, at least for Ford F550 motorhomes. Dodge 5500s would be the same. Pickups have lower cabs than even the E-series vans. And, they have kick-up frames after the cab. This means the house it almost twice as tall inside as the cab, which means nobody in the back can see forward unless they lay on the floor. I'm pretty sure this would cause a lot of motion sickness with passengers, beside losing the ability to utilize the cab as living area since the seats are too low to swivel around (and, I don't think swivel seats are an option anyways).If you are looking at larger Super Cs, such as a Freightliner M2 unit, then that point doesn't apply.-Another con is the Bosch CP4 fuel pump used in the F550. I still don't trust it. Yes, it seems incidents are less frequent now, but the consequences of losing a fuel pump are too high IMO. Rams used the CP3 so that's not a concern there.More of a neutral point: Don't expect a diesel Class C to be any faster. Yes, power deliver is smoother, and it makes less racket when its working hard. But the diesels still only make 300 horsepower in medium-duty trim. At least at lower elevations, the 3-valve V10 will be able to pull at higher speeds climbing hill most of the time, at least until about 4,000 feet when the altitude starts to become noticeable.One more thought: The Ford and Ram 550/5500 have 19.5" wheels, vs the 22.5" wheels on the 22k and learger Class A's. larger tires generally ride smoother, and also will not be as close to capacity as the 19.5"s.

I have read one rant from a International class 6 motorhome based class C, who said comfort was somewhat like a lumber wagon on rough roads. I guess the heavy duty suspension was not what they where expecting. I guess towing capacity is pretty good, but ride quality can suffer if the RV is not loaded up near it's GVWR, and the springs are pretty solid if at say 3/4 of it's rated capacity. Air ride would really help.Reading the post above, I guess it matters what chassis you are looking at. I was in a F-550 based class C, and it looked pretty nice inside. I was not in the back thinking about how it would ride and the vision out the front window. I guess I would need to take a closer look at that if I ever see another F-550 based RV at the sales lot. When I looked at a 2008 new International based motorhome with full wall slide on the drivers side, I really liked it a lot. But it was only a few months later that I read the review of a International who's owners did not like the rough ride. Air suspension can fix that, but it would be a expensive way to do it.When I was in Quartzsite back in 2000 or so, there was a company that would take a F-450 and change the rear spring pack to be air ride for about $3,500 or so. It involved cutting the spring pack in half, leaving the front section to about 5" in rear of the axle, with a new air spring located there to the frame. Good luck with your motorhome decision!Fred.

I owned an F550 chassis Super C for over 2 years now and have taken it on several trios ranging from 40 mile round trips to local campgrounds to 2800 mile round trips. Here is my short synopsis. Pros:- Load and towing capacity. This was the primary reason for purchasing the Thor Super C. We tow an enclosed trailer on desert trips that weighs a solid 11k lbs fully loaded. It tows like a champ up and down the grades. The f550 chassis has a GCWR of 35k lbs. regular C's don't come anywhere close to this. Neither do most of the gas class As. - Stability. We rented several class a and class c motorhomes before deciding to purchase and none of them felt as stable driving as my super c. With the regular C and class A gassers, I always felt like I was driving something that was right on the verge of its load capacity, regardless of if I actually was. The medium duty chassis just seem better suited for the job. Especially when towing something heavy. Safety? This is kind of pushing it, but having the motor and chassis out in front, especially on the International chassis sure seems a lot safer in the event of an accident than a van chassis or a class A. Cons:Cost. Depending on whether your buying new or used, or what brand, Super C's have a much higher price tag usually. Initially, we were looking at a regular C and hoping that during the times we needed to tow heavy, we could just figure out how to make it work. Becuase frankly, the significantly higher entry fee into a Super C gave me sticker shock. But after much research, I realized if I purchased a regular C or A, I would regret it and probably find out that i couldn't tow what I needed.Btw, here is when we tow heavy. Inside the trailer is a desert truck, quad, multiple motorcycles and gear. Tows amazing.

SitesLook like you are using a Equalizer type hitch. How does that work with a motorhome?

Hi,Diesel Oil change is approximately 4 times as costly.Mileage is better but the difference is eaten up by fuel treatment.RV is quite a bit heavier with diesel engineInitial cost is 15 grand morechanging to winter fuel is necessary in the north

Pros & Cons of a Diesel Super C | Good Sam Community

Explorer1016
Explorer
Mar 05, 2016
The class 5 braking system is much more substantial as well. The Freight liner M2 is available in several series chassis as well. You have the M2 Light with a low horsepower Cummins and Allison 3000 series trans and 19.5 tire/wheel combo then you can also get a heavier M2 chassis with higher tow capabilities, 19.5 tire/wheel combo and a heavier M2 with the 22.5 tire/wheel combo. Navistar offers similar chassis combinations.
Explorer1016
Explorer
Mar 05, 2016
The F550 and the Ram 5500 only share the cab of their so called pickup counter parts. The chassis and drive train components are larger. As an example, my F550 utilizes the Dana 110 series read differential and the Dana 60 front differential. They share the engine but on the class 5 chassis series and above the horsepower is derated but the torque is still there. Steering components are heavier as are springs and perches. Etc.
AAFD
Explorer
Mar 05, 2016
To me you have two different classes of Super C, Pickup based units (i.e. Ford F550 and Ram 5500) and large Freightliners.

There is a big difference, like air ride and brakes, 22.5 tires vs 19.5, larger motors (all though not always).

Just my .02 worth.

KC
anav8or
Explorer
Mar 05, 2016
We currently have a Jayco Seneca which is built on a Freightliner M2 chassis. Previous to this, we had an E-450-based Thor Chateau.

Things we like:
- A bunch of additional interior space. With the main slide out, we can throw a couple of beanbags on the floor and spread out. The Chateau was rough on rainy days - just not enough room to relax.

- Huge improvement in exterior storage

- Extremely comfortable to drive. In the Chateau, I felt like I was constantly fighting the wind and passing trucks. I was exhausted at the end of a day of driving. The M2 doesn't get blown around at all.

Mileage has averaged around 10.5 mpg and most of our trips involve towing a Honda CR-V. Power up grades isn't tremendous, but we rarely drop below about 55mph. The Ford V10 did a bit better power-wise, but we were getting 7-8 mpg.

The ride in the Seneca is pretty stiff with the tires at max pressure. Once I had our rig weighed, I adjusted the pressure down and the ride improved significantly.

Overall, we're extremely happy with the Seneca. We've done a couple of multi-week trips (2 adults, 3 labs) and it has been great.
Sites
Explorer
Mar 05, 2016
I think I would have a harder time trying to find 20k lbs of stuff for it to tow :B

rjstractor wrote:
Dune Hauler wrote:
At this point I am looking into a 600HP Freightliner Cascadia based Super C, that will pull a 20,000lb trailer with no problems.

No kidding, 20K is a light load for that chassis. Those class 8 based Super Cs are really in a class by themselves.
rjstractor
Nomad
Mar 05, 2016
Dune Hauler wrote:
At this point I am looking into a 600HP Freightliner Cascadia based Super C, that will pull a 20,000lb trailer with no problems.

No kidding, 20K is a light load for that chassis. Those class 8 based Super Cs are really in a class by themselves.
Explorer1016
Explorer
Mar 04, 2016
I have owned 5 gas 3/4 ton and 1/2 ton pickups and 3 diesel 3/4 ton and 1 ton pickups. Now I own an '08 F550 4x4 diesel Super C. Most of the Super C's are geared low because they are focused toward the towing crowd. We tow an enclosed trailer with a full width workbench (empty trailer weighs about 4000#) then I load it up with my 5000# Jeep rock crawler and every tool I can think of plus jacks, jack stands, coolers, extra gear, etc. My trailer weight comes in at about 9000+# loaded. You will have a very difficult time finding any gasser that will tow that type load cross country. We drive from Eastern Missouri to Moab almost annually for the Jeep Safari, we frequent Colorado and go east to where ever we need. Pulling through the Rockies is very hard on a tow rig and the gassers just have a hard time doing this. i'm not sure you can buy a gas powered RV with that high of towing capacity. My mileage is only about 8mpg but I am running a GCWR of about 28,000#'s. My Chassis weighs more that some other Super C units due to the 4 door Lariat Cab and 4x4 drive train and I have 3 slides.

The drive train and under carriage of a Class 5 or above chassis has bigger components than a Typical Class C. Even the gas based Class A chassis's aren't built as heavy as the Class 5.

I run 14 Ply Toyo's on all 4 corners and my rear duals load carrying capacity is higher than the empty curb weight of my RV. My load capacity on just my rears comes in at 15,000#'s.
Dune_Hauler
Explorer
Mar 04, 2016
I have had a 5th wheel, class C then to A, now in a Super C. The only complaint is less living space verses length. The towing capacity structural strength and overall build of higher end Super C's can't be beat in my opinion. At this point I am looking into a 600HP Freightliner Cascadia based Super C, that will pull a 20,000lb trailer with no problems.
RobbieH
Explorer
Mar 03, 2016
I have never put any type of fuel treatment in any diesel I have ever owned. It is not needed.

Oil change costing 4x as much is not true. And many diesels go much farther on an oil change than a gasser. For example, my 2006 Dodge's oil change interval was 15,000 miles. 12 quarts of oil, and oil filters are not too expensive (I get the Fleetguard Stratopore filters for $14 from Geno's Garage). I had my Super C's first oil change done at the stealership (Ford house) and it cost just at $100. I don't think a V10's oil change costs $25. And I could have done it myself far cheaper than $100.

I got mine, like Sites, for towing capacity. 95% of the time, I have 7,000 lbs behind me. And even in the Rockies, I'm in the passing lane, not the slow lane.

Initial cost for diesel is often offset by resale value, in some cases the difference in resale value can be more than the initial cost of the diesel. When I got my Super C, I sold my Ram for $25,000. I paid $32,000 for it new. Try that with an '06 gas truck.

I have never had to buy new spark plugs for any diesel either. :D
pianotuna
Nomad III
Mar 03, 2016
No, I was not referring to DEF. I was referring to a product I used that appeared to work well to make the diesel run more smoothly.

BTW I drive my 28'5" 13,700 lb v-10 @ 49 mph and get an average of 11 MPG US.

I have no difficulties of any kind in the mountains, but of course do not get the same mileage as on the prairies.

Sites wrote:
pianotuna wrote:

Mileage is better but the difference is eaten up by fuel treatment.

I've seen the "diesel is better than gas because of mileage" argument a lot over the years. Not just RVs, but trucks in general. It's kind of a pointless statement if you think about it. Since in 99% of situations, there is absolutely no way the MPG gained will offset the initial premium cost associated with going with the diesel option.

And honestly, the fuel treatment (I assume you're referring to the DEF fluid?) really isn't a big deal. Its cheap and at least my MH seems to consume very little (I've only filled the DEF reseivor twice in 7k miles.) The second time was when I took it to my Ford dealer to change the oil and they just included it in the service for free.

Bottom line, go with a diesel for the additional power over a gasser. Not because of mileage.