MODUON

When you build an off-road trailer from scratch, the frame isn't just a piece of metal—it’s the backbone of every expedition you’ll ever take. Out on the corrugated dirt tracks of Southern Africa, there’s no room for shortcuts. Every weld, every bend, and every material choice comes down to one goal: building something rock-solid that brings you home every single time.

Here is a look behind the scenes in the workshop as the Moduon M1 chassis came together.

There is a profound moment in any build that every maker knows. A few months ago, this steel was just cold, raw C-channel sitting quietly on a rack in a warehouse, inert metal with no purpose. Today, through measurement, heat, sweat, and intent, it has taken shape. It is no longer just raw materials; it has become the chassis of the Moduon M1.

We deliberately chose mild steel over aluminum or stainless. Mild steel is a material that is rigid with some elasticity, it handles cyclic stress and strain under constant flex without getting brittle. Aluminum might save a bit of weight, but under endless trail vibrations, mild steel absorbs repeated stress far better without fatigue cracking.

You will also notice we strictly avoided closed box sections. Enclosed tubing is a trap for mud, dust, and water that rots a frame from the inside out. Keeping everything open means it’s visible, cleanable, and perfectly prepped for hot-dip galvanizing.

Instead of standard square tubing, we went with heavy-duty 100x50mm C-channel.

In a traditional box frame, if a wall starts buckling under a massive hit, you can lose up to half your strength instantly. C-channel handles bending forces predictably, gives us incredible structural integrity, and leaves no hidden cavities.

The rear end takes a beating on steep drop-offs, so we integrated a heavy steel bumper and dedicated light housings for the LED rear lights. The light housings are easily removeable without having to unbolt additional panels/covers, and the LED lights can be replaced without removing the light holder at all.

Beyond keeping the lights and wiring harness protected, this layout leaves a nice, open center cavity low down in the chassis. That’s prime real estate for water tanks, keeping precious weight centered and close to the ground where it belongs.

Not everything goes smoothly on the first pass, and if you’ve ever built anything in a workshop, you know the feeling!

When test fitting the mudguards, we ran into a problem, the press-brake bend was slightly off. It hadn't been measured right after bending and went straight to coating—a hard-learned lesson to measure at every stage.

Instead of scrapping them immediately, we put them to work as physical drill templates to line up mounting holes before getting the final replacements done right.

For this first prototype frame shown in the picture, we deliberately chose not to hot dip galvanize it right away. Because it was our initial chassis build, we wanted to test every component thoroughly on real tracks first. Hot dip galvanizing a frame too early means that if you need to modify a bracket or drill an extra mounting hole later, you cut through the protective zinc layer and compromise the barrier. Notice where the A-frame meets the main chassis: there are no cuts or welds here. It is one continuous cold-bent section. Cutting and welding high-stress junction points creates heat-affected zones that love to crack under continuous flex. By keeping the steel continuous through the bend and adding a relief section right on top of the chassis junction, stress distributes smoothly across the metal.

The Setup:

• Tow Hitch: 2.7-Ton braked coupler unit.
• Axle: Heavy-duty solid axle on leaf springs with auto-reverse brake release.
• Why Leaf Springs? Simple, lightweight, cost-effective, and practically indestructible. Out in the bush, straightforward reliability wins every single time over complex suspension setups with too many moving parts to fail.

• Foldaway Gearbox Jockey Wheel: It swivels up out of the way during travel—no more wrestling to unclamp, remove, and stow a heavy jockey wheel in your boot. Plus, the internal gearbox makes cranking effortless.

• Rear Stabilizers: Twin drop-down legs at the back mean when you climb into bed at night, the trailer stays rock-steady without rocking or tipping as you move around.

After hours of design, cutting, measuring, and grinding, standing next to the finished frame alongside my dad made every bit of effort worth it. It’s more than just steel—it’s the foundation for incredible adventures, built with intention, passion, and zero compromises.

Ready for the next phase of the build!