I'll try in english, probably easier for you
Have a look here
https://www.roboternetz.de/phpBB2/motordrehmoment.php
(in German)
You have to measure the the required Newtons on your byc. brake, and then you can find the motor power you need
You're tying to make something like ABS on your bicylce ? I would not rely on that.
G.luck
Lesezeichen