How We Chose Our Expedition Truck Build: F-550, Gas vs Diesel + a Moving Box
10 minutes ago
4 min read
Once we decided to leave the van for an expedition truck build, the real questions started. Which truck? Gas or diesel? A custom composite box like the big expedition rigs, or something simpler? Duallies or singles? These were the decisions that shaped everything else in our build, so here's how we made each one, and how they've held up after years of living in the truck full-time.
If you want the backstory on why we left van life in the first place, we wrote about that in Why We Quit Van Life for our DIY Earthroamer. This post picks up right where that one leaves off.
The formula: a chassis cab with a box on the back
We'd always dreamed of owning the ultimate adventure rig, but with EarthRoamer-type builds costing upwards of a million dollars, that was completely out of reach. So we borrowed the formula instead: a medium-duty chassis cab with a separate box behind the cab. It's the same basic idea EarthRoamer-style rigs use, just built by us instead of a factory.
After three years in a Sprinter, we'd outgrown van-sized everything. A medium-duty truck gave us real square footage, real payload, and enough structure to build the systems we'd been dreaming about: a big electrical system, an indoor shower, heat, AC and a garage for our bikes.
The truck: a 2022 Ford F-550
We landed on a 2022 Ford F-550 Super Duty chassis cab with the 7.3L V8 "Godzilla" gas engine and engageable 4x4. It showed up as a plain white work truck with dual rear wheels and no box at all.
Years later, two things about the truck itself still stand out to us. True 4WD with extra ground clearance gets us places a van never could. And the separate four-door cab gives us a quieter drive, with everyone riding up front in the truck instead of back in the camper.
Gas vs diesel: why we went gas
This is the question we get asked more than any other. We chose the 7.3L gas V8 over the diesel option, and it came down to three things:
Cost. The gas engine was about $10,000 cheaper than the diesel when we bought.
Weight. It's about 500 lb lighter. When every system you add pushes you closer to your weight limit, 500 lb up front matters.
Service. A gas engine is easy to get maintained and repaired almost anywhere we travel.
We didn't give up capability for it. The 7.3L has plenty of power for us fully loaded, and we haven't found ourselves wishing for more. Years in, it's been amazing for us, and cost, weight and serviceability are still exactly the reasons we'd give if we were choosing today.
The box: why an industrial moving box
A lot of expedition builds go with a custom composite box. We put an industrial moving box on our truck instead, the kind you see on delivery trucks, made by Morgan. Inside it's roughly 14 feet long and about 7.5 feet tall and wide, with an aluminum skin riveted to galvanized steel posts.
Here's why it worked for us:
Square walls. After building out a van's curves, this was a dream. Square cabinets fit square corners.
Steel studs we could bolt to. Rivnuts in the studs became one of our go-to techniques. The bed, cabinets and shower all bolt into them.
Space. About 110 square feet of floor, way more than the van.
The ramp. The coolest thing about this box is the drop-down rear door. We wanted it from day one because we planned to turn it into a patio off the back of our living space. That patio is probably the best part of the whole build for us.
Before we cut a single thing, we rode our mountain bikes up the ramp and into the empty box. Those bikes ended up driving the whole layout: the bed height, the garage height, all of it traces back to "will our bikes fit under here?"
Duallies vs super singles
The very first thing we changed on the truck was the wheels. It came with dual rear wheels, and we didn't want the duallies for a lot of reasons. We switched to 42" Continental MPT81 super singles, one tire per side in back, with a 2.5" lift to fit them.
Ride, traction and clearance all improved a lot, and we can air down really low for driving on beaches in Mexico. We got almost 30,000 miles out of our first set of tires.
One honest lesson: our original steel wheels cracked. That's a real problem, and it's exactly why we carry a full-size spare (it weighs about 250 lb, and we've used it multiple times). We replaced them with two-piece aluminum wheels from Stazworks, and they've been the clear upgrade.
A note on weight: we weren't weight-obsessed on this build, and the freedom a medium-duty truck gives you is a big part of why we chose one. We still made lighter choices where they were easy, like 1/2" cabinet material instead of 3/4". Whatever you build on, know your truck's real limits from the door sticker, and weigh the finished rig at a CAT scale before you trust any number, including ours.
Watch the whole Expedition Truck Build
Our start-to-finish video covers the truck, the tires and the whole year-long build:
What we'd do differently
If we built another expedition truck, we'd choose a composite box with a cab-over section instead of our Morgan box. That extra space over the cab would free up more living space inside. We'd also get our doors and windows cut and sealed in before the exterior coating went on (more on that in a future post).
What we'd keep no matter what: the F-550, the gas engine, and that rear ramp.
Comments