I wanted a vehicle that was stable, practical, and unmistakably mine, so I built Ungetüm—a custom three-wheel electric bike. The chassis combines salvaged bicycle parts, a welded frame, and reclaimed car batteries. It is not light, it is not subtle, yet it moves reliably at 18 km/h with huge low-end torque.
Concept and Planning
The brief was simple: create an electric vehicle that could carry cargo without tipping over. A trike layout solved the stability problem but introduced new challenges around steering geometry and braking. I sketched variations, selected one that balanced weight distribution, and mapped which donor components I needed to source.
Electrical System
A 650 W hub motor paired with a compatible controller formed the propulsion system. I repurposed old car batteries for energy storage, which required careful monitoring because of their uneven history. Wiring harnesses were assembled by hand with a focus on accessible troubleshooting—every connector is labelled and reachable.
Mechanical Build
The frame blends wooden reinforcements and steel tubing. Welding the main joints established structural rigidity, while bolted connections allowed later adjustments. Steering linkages were prototyped multiple times to eliminate wobble. The final geometry maintains confidence at top speed without sacrificing maneuverability.
Challenges and Fixes
- Motor control tuning: Early tests produced jerky acceleration. Reflashing the controller and smoothing throttle inputs delivered predictable torque.
- Weight management: The 60 kg frame pushed standard bike brakes to their limit. Upgrading rotors and balancing weight across the axles improved stopping distances.
- Structural fatigue: Stress-testing revealed weak joints that were re-welded with gussets to prevent cracking.
What I Learned
- Vehicle projects live or die on safety—brakes, steering, and electrical insulation cannot be afterthoughts.
- Rapid prototyping with wood and steel accelerates learning before committing to final welds.
- Documenting wiring and component layout saves hours when troubleshooting under time pressure.