Bosch ebike motor, dual chainring

Bosch Ebike: Double Chainring Motor Set Up Coming?

Electric mountain bikes are constantly evolving and their market has been dominated by Bosch until now. Over the last few months though a bunch of new producers have entered the market. Yamaha is having a huge success among ebikes fans. Haibike chose Yamaha to motorize their e-mtb Sduro series. Its success is due to two main factors: the higher torque of its motors and the option to use a double chainring set up, which allows a wider range of gear ratios. 

Many users of e-mtbs with a Bosch motor complain about the fact that the number of gears is not enough when you go uphill (beacause of the presence of just one chainring).
The problem is bigger than it seems: Bosch’s motor is at its best at a high cadence, which is impossible to reach on a steep hill with a standard chainring. At a low cadence the risk of being forced to stop is high because the motor can’t “push” efficiently enough.
That’s why there exist many unofficial “kits”, unapproved by Bosch, to modify its motor: one solution is to install a smaller chainring; it is also possible to install a dual chainring setup – yes, there’s enough room for both chainrings, though you have to manually shift between the two.

Bosch is a big company and it’s constantly monitoring its market. They have noticed the big success of Yamaha’s double chainring set up, and they decided to meet their customers’ needs by creating a new motor which is equipped with a double chainring.

This is the conclusion we came to after seeing the patent Bosch presented a while ago (found on the internet by
From the technical drawings we can see two chainrings which seem to have 16 and 22 teeth (even if they might look small, remember that Bosch’s motors have internal gears: small chainrings actually correspond to standard chainrings).
In the patent it’s clearly stated that this solution could be installed on an “electric vehicle”.

The patent was released in July 2014 but it was actually created in January 2013. Bosch engineers probably had all the time they needed to realize the definitive version of a double chainring set up motor. Bosch usually displays its new products at Eurobike, a fair that takes place yearly at the end of August. Should we expect a prototype for that date? Very likely!

We think that this episode shows the huge importance of competition in every field. If there are more players operating in the same field, they’re all pushed to offer better products… And consumers have everything to gain from it!

Bosch Ebike: Double Chainring Motor Set Up Coming? last modified: 2015-02-16T10:24:29+00:00 by Elisa

Leave a Reply

Your email address will not be published.