The Duowheel is a fun to drive MOC that is made up of a driving mechanism suspended between two large wheels.
The wheels are driven by two L motors with torque limited by two clutch gears on each axle to prevent the mechanism flipping over (most of the time, anyway). The battery box is mounted low and also helps minimise flipping.
Each wheel is made up of 46 tank treads turned inside out supported by four axles. The wheel is attached to the driving mechanism by a 36 tooth gear.
While it can be a bit tricky to get started (you need to give it a bit of a nudge, then you can get going), the Duowheel is very fun to drive and quite sturdy.