In the Spotlight: Ram 5500-Host Mammoth Flatbed Rig

They go by several names—truck bodies, flatbeds, service bodies, utility beds—but for today’s truck camper rig, they all do the same thing, increase storage, and in many cases, provide additional capability. Michael Nyholm of California had a truck body built for his rig, a Ram 5500 mated with a Host Mammoth, one of the biggest if not the biggest rig you can build with a traditional slide-in camper. We first saw Michael’s setup at the 2020 Truck Camper Adventure Rally in Quartzsite and were impressed with its good looks, size, and capabilities. Indeed, the basic combo would have been enough to impress anyone, but when you couple the beastly pair with a matching truck body, it puts it over the top. To explain the more intricate details of his rig and how he built it, we spoke with Mike.

We love your rig, Michael. What inspired you to build it and how long have you owned it?

Michael Nyholm: Our Host Mammoth camper was built in 2014 and sold to us in September of that year. We had a Montana fifth wheel with bunks at the time. Knowing we would be traveling with just the two of us and our dogs, we were attracted to the layout. We had a 2008 GMC diesel dually and paired the two together for a few years. So the camper is about six years old and an early generation of the Mammoth.

Let’s start with the truck. What is the make and model and what are the truck’s specs?

Michael Nyholm: The truck is a 2015 Ram 5500 chassis cab with a 60-inch cab to axle wheelbase. I found it online out of state and it had sat on the dealer’s lot for a year. It’s a crew cab, 4WD and is a slight upgrade having the SLT badging. It has the diesel-mated to an Aisin 6-speed automatic transmission. It’s the standard 325 HP and 750 pounds torque with a 4:88 rear end. That was a consideration at the time however fuel consumption is about what I expected and the truck was discounted enough to make it pencil out. It has the factory exhaust brake and with the tow haul feature, it’s a pleasure to drive in the mountains.

It has the single 52 gallon fuel tank (there is an optional additional 22 gallons available within the frame) and it has a GVWR of 19,000 pounds and GCWR of about 37,500 pounds. It’s registered for 30,000 pounds with the state of California. The SLT badging added a sliding back window, audio upgrades, and some other feature comforts.

What upgrades, if any, were made to the truck’s suspension to carry your camper?

Michael Nyholm: Really nothing. We’re considering upper stable loads, but that’s about it.

What other upgrades were made to the truck?

Michael Nyholm: We added chrome nerf bars to ease getting in and out and installed a ball mount to clamp a Garmin Overlander unit just above the dash. It incorporates a wireless camera mounted in the camper that has an on demand view of anything behind you. It’s nice for towing our Jeep Wrangler.

Are the engine and transmission stock?

Michael Nyholm: Yes, completely stock. Essentially, the truck is as it left the factory.

Can you tell us more about the wheels and tires?

Michael Nyholm: They are factory optioned 6×19.5-inch Alcoa polished aluminum wheels matched to Continental HSR 22570R 19.5 rated at 3,750 pounds each. There is only 30,000 miles on them and they might age out before wearing out. I had to buy a steel rim and mount a spare which are located inside the utility body.

Why did you decide to buy a Host Mammoth?

Michael Nyholm: Three reasons: the two hallways to get out of bed without disturbing your spouse, plenty of light through the large windows, and the large dry bath. Coming from a large fifth wheel, it seemed that we didn’t have to sacrifice any amenities to be comfortable. We have pushed the capacities of the large tanks with extended stays, and a single solar panel helps with the two stock 6 volt batteries.

Those are great reasons. It is a spacious camper. Did you opt for the standard Mammoth floorplan?

Michael Nyholm: Our purchase was back in 2014 and it was actually specified by another person who couldn’t take delivery. It had everything we thought we needed, three slides, a dinette and a small couch.

What features do you like best about the Host Mammoth? What it the floorplan, it’s “mammoth” size, or was it the camper’s aluminum frame with the crowned roof?

Michael Nyholm: We were drawn to the open floor plan when the slides are extended, storage, and fit and finish. I knew about the structure, construction and components after touring their facility in Bend. I would encourage anybody considering a Host to make an appointment to view the process. My early years of being a certified welding and fabricating background with an OEM heavy duty trailer manufacturer, I appreciated how the wiring harnesses, plumbing and even fasteners are neat and orderly. Windows openings are framed all the way around.

Why do you think the Host Mammoth is such a good seller?

Michael Nyholm: I think it’s because when Host introduced the Mammoth, they didn’t just run a production of say 300 units and then re-grouped to see if they could run another 300 for the same costs or cheaper. There has been innovation along the way and I think that really helps with the quality. They will also build a camper to your specifications. I’ve noticed two exterior changes since our purchase. You know how grills and mirrors can help identify the year of a truck? Exterior graphics changed about 2017 and the one-piece molded front cap is new this year.

Did you opt for one of Host’s Lithium Off-Grid Power options?

Michael Nyholm: Unfortunately, this wasn’t an option for our year of camper, but something we would consider going forward.

What are the specs of your camper?

Michael Nyholm: The Mammoth’s tanks are big—65 gallons fresh, 51 gallons grey, and 32 gallons black. The camper is also equipped with two 30-pound propane cylinders. The 150 watt solar panel helps keep our four 6 volt 224 amp AGM batteries charged. I know it’s not balanced, but when we boondock, our capacity can carry us a long time. There is also an onboard Onan 2500 generator that we rarely use that we can use in a pinch.

We had a great time two years ago re-stocking our son and his girlfriend along the Pacific Coast Trail. They through hiked it for seven months and I think four times we intersected the trail for a food and shower reunion. On the trail, friendships are made and at times we were feeding up to eight to 10 people at a time. It was really special to meet these people from all over the world and make the next 36 hours for them a time to gather and relax.

Many companies have issues with their slide-outs. Have you had any issues with the Power Gear slide-outs found in your Host Mammoth?

Michael Nyholm: Never. I’ve heard criticism about having to operate the slides to use the bathroom while traveling and how that can shorten the lifespan. They are heavy duty!

What mods, if any, have you installed in your camper?

Michael Nyholm: Mostly storage related. Moved the stereo in the mantle to one side that created a cubby for electronics and another plug off the inverter. Reversed the swing of the closet doors with pull-out wire baskets and two additional storage behind cherry stained doors. We found a five-bottle wine rack that I wrapped with backer rod to protect the bottles. Motion sensor flood lights with rocker switches installed within the reading lights in the bedroom. New converter, hooks for hanging towels, and a wireless back- up camera inside and just under the window valence. This is on demand and synced to the Garmin in the truck. Removed a 1/4-inch brass tee at the propane manifold and installed a cross, giving me a propane plumbing connection for our little Webber. Took the regulator off the BBQ and had a 12-foot hose made with swivel fittings. Works awesome and no little green bottles.

The truck body really makes your rig stand out. Can you tell us more about it and what it’s outfitted with?

Michael Nyholm: I had heard about Douglass Truck Bodies before and when a friend shared a build sheet for his mobile welding company, he suggested I call them. After several calls, I opted for a 9-foot bed with adjustable shelves in the three taller boxes, a box to carry the spare tire, jacks, and tools, etc. on the front passenger side. Within the cabinets are two batteries in series that connect to the camper batteries, 120 volt air compressor, hoses and cords and tarp, inflatable kayak with oars and life jackets. A tow frame for the Jeep, fly rods, a couple extra chairs and whatever we might need at our destination.

The floor of the bed is 8-feet long with a 12-inch wide cabinet towards the cab (9-foot bed) for long and narrow stuff. It has a beefy spray coating on the floor, the inside walls and over the top. Industrial paint with a different chemistry matches the OEM color of the truck. I had them install a Torklift 48-inch-long SuperTruss and magnum hitch. Douglass installed frame mount removable extension for our Torklift FastGuns. They also offer another tie down system that seems more popular. You can really customize these with different size boxes, electric locks, roll our drawers, all depending what can fit on your wheelbase.

How much does your entire rig weigh at the scales?

Michael Nyholm: The truck went to Douglass at 8,400 pounds and a weight slip with most of what is stored in the utility body totals 11,200 pounds. I weighed the camper loaded on our old GMC and the camper came in at 6,300 pounds. Combined, with passengers and dogs, water, and beer it’s about 18,000 pounds.

Wow, that’s a heavy rig. It’s a good thing you bought a 5500. Is it true that the state of California requires you register it because of the truck body and that you have to have it weighed on the highways like standard commercial trucks?

Michael Nyholm: Yes. It’s a little controversial here. If you have an 8-foot or longer non-factory truck bed and your truck is registered over a certain tonnage, you are expected to go through the scales. Even though signage always says no pick-up trucks, if you’re a one-ton truck or bigger with any custom bed, including flat, utility or box, you need to stop. When you purchase a new truck (probably exclusive to one-ton vehicles), this form must be filled out.

I was complimented and warned a couple summers ago when getting fuel along Highway 395. A guy came over to talk about our combo and said there were portable scales set up by our DOT and the officer there loved to chase 4500 and 5500 trucks that bypassed his set-up. I think the consensus is you will most likely get green-lighted going through. If you bypass, you open the chance of being pulled over and fined.

Well, that’s good to know. What kind of places do you take your Host Mammoth truck camper rig? We assume you like to do a lot of boondocking in it?

Michael Nyholm: We’re about 30 minutes from the Sonoma County coastline and love hanging out there. We combine a week of spring training and Death Valley, Arches, Natural Bridges, and other destinations during mid March. In the fall, it’s the 305 corridor catching fall colors, hikes, fishing and kayaking. We also do an annual trip by Mt. Lassen. Alabama Hills is awesome and we’re looking to discover many more places. As I’m nearing retirement, we’re excited to begin planning long trips exploring more destinations.

Anything else you’d like to tell us about your rig?

Michael Nyholm: It took some time and coordination to make it happen. On paper it looks like in 2015 we pushed our chips “all in” when in fact the camper was picked up in 2014 and the truck was finished in the fall of 2017. At one point, the camper was left with Douglass for the final fit and mounting of the utility body, then the camper was loaded. For others considering this route, there are even more options for cab and chassis trucks with the flexibility of flatbeds with boxes/bins mounted under and over the beds. And now Chevy/GMC has entered this market once owned by Ford and Ram. We’re very happy with our choices and have had enjoyed the relationships made with both companies.