Alongside the talk From Bit to Bulk, GeDy TrAss followed a project with the students of New York City College of Technology (City Tech, CUNY) within the Emerging Scholars Program, the college’s undergraduate research programme: “Innovative gearbox for greener e-bike”. The project ran in spring 2025 and again in spring 2026, in May.
The starting point is a new e-bike architecture. The electric motor no longer drives the wheel directly at variable speed: motor and pedals feed a gearbox that keeps the motor as close as possible to its most efficient speed, and the motor can also recharge the batteries. The students worked on real data: 125 kg for bike and rider, a 30 inch wheel, a 500 W motor at 2500 rpm, a 7:1 final drive and three targets to meet (45 km/h in electric mode, a 30% slope, 25 km/h on a 10% slope).
With a Python script they computed the required power, the wheel and gearbox speeds, the gear ratio and the torque requested to the motor, and checked that the working point fitted the motor characteristic. They then used GeDy TrAss, from the browser, to define gear type, geometry and profile of the gear pairs that deliver that torque and ratio.
The last step was the most tangible one: the students built the gear pairs they had designed with 3D printers, to hold in their hands the result of the calculation.
