Bosch’s flagship mountain bike system uses a mini drive ring with internal gearing to send its power to the drivetrain. There’s some resistance in the system over 25kph, but when you first press down on the pedals there’s an impressive surge of power, and it offers good support over a wide cadence range.
Its size has an impact on the width of the cranks (the Q-factor) as well as the chainstay length of the frame, and it’s not the lightest system on the market at 4kg for the motor. On the other hand, Bosch is the most established player on the market, and its system has proven itself over many years.
Bosch produces three display units of varying sizes. The most common units fitted to mountain bikes are the compact Purion and larger Intuvia. Should you want to stay in touch on epic rides, there’s even a Nyon unit that links to a smartphone, records data and displays navigation, texts and email.
Bosch offers four ride modes (Turbo, e-MTB, Tour and Eco) with a single walk mode. The e-MTB is the intelligent mode, offering tailored assistance from 120 to 300 per cent, depending on cadence and pedal pressure. Two external batteries (400 and 500Wh) are available and there’s a 500Wh PowerTube battery for internal use. Charge time for the 500Wh battery is 4.5hrs.