This 3-wheeled BMW R100 custom build takes inspiration from pre-war racecars

Designed by Cumpert Contraptions, this custom BMW build is just that – an oddball contraption that captivates the eye with its retropunk demeanor. Resting on three wheels instead of the usual two, this quirky beauty once used to be a 1992-model BMW R100R Mystic, which Tim Cumpert got his hands on for his mad-scientist project. He sawed the front off, replacing it with a chassis taken from an ATV, and built out his vision using that as his framework. “The three-wheeler was inspired by pre-war racing cars, which I am a big fan of,” he told Bike EXIF. “When I started this project back in 2012, Morgan had just released their new 3 Wheeler. But the main drive for this project, was that I wanted to try my hand at sheet aluminum fabrication.”

Designer: Tim Cumpert

Cumpert’s fascination with aluminum fabrication really defines his project’s overall aesthetic. The pre-war energy is strong with the exposed sheeting and visible rivets all along the side of the vehicle. Cumpert started off with sketches, which he then made a 3D CAD file of and CNC-machined to a 1:3 scale. This helped him iron out any kinks and build the large wooden blocks that he would then use to hammer out his aluminum sheet on.

As one could imagine, simply gluing an ATV to a motorcycle isn’t quite an elegant or functional solution. However, both the frames were luckily the same width, which made it pretty easy to line them up. Most of the ATV’s front end is still intact, including its steering linkage, suspension arms and shocks. The hybrid bike (although not your conventional hybrid) uses the ATV brakes on the front and the BMW brakes on the rear too.

The bike’s 3-wheel format isn’t the first thing you notice about the bike, though… it’s the unique low-hung frame. It somewhat resembles the BMW Alpha by Mehmet Doruk Erdem with its crouching appearance and front-heavy torso. The boxer motor sits a little more towards the front than usual, but is complemented perfectly by the two wheels ahead of it that really help distribute the mass in an elegant way. In order to really drive home the vintage racecar aesthetic, the 3-wheeler also uses a repurposed Kawasaki Versys windscreen on the front, and sticks to a relatively nude paint job, with just a flash of red near the seat.

“This is my first sheet metal project,” says Tim Cumpert, “so I designed the shape of the three-wheeler to be mainly simple forms. Most of the body was made using a roller, while the front grill and side pods were hammered over MDF bucks, with a bit of English wheeling to smooth things up. The most tricky part was the rear section, which is made from around six parts.”

The bike’s more of an exploration of possibilities rather than being something that’s essentially road-legal. Cumpert mentions that driving it takes getting used to, especially the handling, considering its 3-wheeled format. “It will lift a wheel on cornering, so you need to move your weight towards the inside wheel when turning”, he says. “I have a list of handling mods to try now. I think the seat needs lowering and handle bars rising a bit to make it easier to move around and see where you’re going, plus I’d like to try an anti-roll bar on the front.”

Images via Bike EXIF