As an example, check out this six-wheeled truck, which recently sold in the Netherlands.
To accommodate the extra axle, there's a custom subframe. There's also a 3.937-inch (10-centimeter) suspension lift. The extra height allows for installing new wheels with big, off-road tires.
Built as a one-off in 2020, the six-wheeled Mercedes X-Class certainly has a striking presence. The exterior is a brown metallic color that evokes the shade of rootbeer. There are chrome bumpers at both ends, and huge, matte-black fenders accent the sides. A tubular-metal style bar from Carlex Design runs along the sides of the bed and over the roof. Inside the cargo area, there's diamond-pattern steel. A "6 Wheeler" decal adorns the tailgate.
The interior remains largely stock. There are black leather seats and silver trim. A six-wheeler emblem appears on the passenger side of the dashboard. The camera system still works, even with the extended bed.
The X350d drivetrain remains stock. A 3.0-liter turbodiesel V6 makes 255 horsepower (190 kilowatts) and 406 pound-feet (550 Newton-meters) of torque. It runs through a seven-speed automatic. There are no obvious controls for the drivetrain in the cabin, which suggests this might be a full-time system.
Carlex Design toyed with the idea of building an X-Class 6X6 and released two renderings of trucks like this. The first of them looked more production-ready but still had a pumped-up body with a hood scoop and light bar on the roof. The example that came next was more fanciful by adopting panels with visible rivets onto the body, a carbon-fiber hood, and a gold-painted pickup bed.