Update your Robak 2 with this 19:1 gear reduction mod, which increases torque at the expense of top speed. Benefits include:

• Higher acceleration
• Improved climbing capacity
• Reduced motor startup hesitation with sensorless setups
• More energy efficient at low speeds.

You'll need to print the updated version of the TopDeck rear 

and remove the thin piece of plastic from the Chassis using pliers.

Fasteners

Bearings

• 3x 15x10x4mm bearing
• 2x 10x5x4mm bearing