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Bosch Vs Yamaha: Part 1: The Motor

Motor Comparison

Both Bosch and Yamaha use crank drive motors, they are integrated into the bottom bracket area and drive on the crank which gives full use of the gears and a natural efficient feel for the rider.

Bosch and Yamaha use high performance crank drive systems that optimise the use of 3 sensors – Cadence, Torque & Speed. These sensors are measured 1000’s of times a second to create a very responsive, efficient & natural rider experience. 



You will notice both the Yamaha and Bosch motors are similar shapes. They are also similar sizes, but the Yamaha motor is slightly smaller than the Bosch. 

The Bosch motor is internally geared, so it features a small drive sprocket. This sprocket turns 2.5 times to each crank rotation. This enables a higher ground clearance but still offers standard gear ratios. It’s also near impossible for the chain to come off.

You will notice the Yamaha motor uses a regular size sprocket and the drive is not internally geared. Yamaha have created this system to be compatible with a double ring set up on the front so you can have a larger gear ratio between the 2 sprockets.

The Bosch drive uses a ISIS crank fitment whereas the Yamaha drive uses a square taper crank fitting.

Motor specifications, comparison side by side – 


Bosch Motor

Yamaha Motor







Drive Sprockets


1 or 2

E.I Compatible



Light Outputs



Assisted Speed

Upt to 20MPH

Up to 28MPH on "S" models

Up to 20MPH


Very similar specifications between both manufacturers. Although the Yamaha system does have a little more torque, in fact we list a continuous torque figure but it will actually peak at a whopping 80Nm!

The Yamaha system offers slightly more assistance too and the power comes in a little earlier than the Bosch motor. Although the power curve is smoother on the Bosch system. Yamaha call this instant power ‘0 cadence’, it is there right from the off.

Other differences:  The Xduro line is also considered a little bit of a step above in terms of builds.  So you'll generally find similar models to be equipped/specked out a little better in terms of overall components used.

Our overall feedback:  We find that customers coming from a more traditional cyclist background tend to gravitate to the Xduro/bosch system as the system feels smoother and more like what they're used to on a traditional pedal bike.  That said, if you're doing some steep climbing or a touch on the heavier side, then you'll find the Yamaha system will not disappoint.  For where our shop is located, this system tackles the steep grades around here better than just about any other bike on our floor.  

Another point to consider.  All Sduoro/Yamaha systems are currently rated for a max speed of 20mph, while the Xduro/Bosch systems have at least 6 models labeled (S) which will allow for a max speed of 28mph. 

At the end of the day, don't over think're going to be super impressed with either choice you end up going with, I know we are!

Thanks for reading our article and don't hesitate reach out if you have any further questions about these systems.  

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