Bosch engine tuning at home

Last year greatest ebike story was the introduction of the Bosch middle motor engines. If you are one of the people who are not satisfied with the 25 km/h top speed limitation, here you have a complete guide how to hack the system! 🙂

The smaller engine of Bosch is a pedelec-system with the top speed of 25 km/h; above that you can count on your muscle power only. But the 50 Nm top torque provided by the motor is enough to reach 50 km/h without the electrical limitation.

The principle of this hack is to modify the speed signal sensor, which normally based on the rotation of the rear wheel, by the rotation speed of the crank. So the system will be cheated      by measuring around 30% of the actual speed, and the top speed of the bike will over 50 km/h based on the measurements. 🙂

Here you can see the result:


And here you have the complete tutorial of the rework:

And if you want to know, what is inside the motor, watch this:

I’m not sure if Bosch is happy to see this… 😉


Bosch changed the controller software of the drive unit to look for this change! If your motor came after April 2012, then you have the modified version already. If you try this hack, you will get an error message of 102, and the speed of the bike will be limited to 15 km/h. Currently we don’t have any solution to change the speed limit of the drive unit!