Now and then, you read about the horn button mount breaking. The counterpart to the horn button is the brake lever. The mounting clamp is made of aluminum, and sometimes PVC. The connection is sensitive to impact. A fall or overtightening of the two mounting screws are usually the cause of the mount breaking.
The tightening torque is max. 2 Nm. It is recommended to use a torque wrench. This value is quickly exceeded when tightening by hand. Basically, it's enough to tighten the screws so that the brake lever can no longer be turned. In practice, this point is reached at approximately 1.3 Nm.
Source / Prices:
The knob with clamp is available as a spare part.
- ST7 2022 | ST5 2023 Pinion | ST5 2021 ABS | ST5 2018 | ST3 2022 Pinion | ST3 2018
Stromer-bike.de (35 €) | Fratello.bike (25 € ) - ST1/ST2
Addendum: ST7
Are there any instructions on how to replace the horn button? Cable routing.....
Not one that I am aware of. Stromer will presumably provide the dealers with corresponding work instructions. (unfortunately not public).
The cable runs through the handlebars, over the stem to the omni. To disconnect the plug there, it must be removed. You will also have to open the top of the stem so that you can feed the new cable and plug through.
Alternatively, you can disconnect the existing cable behind the horn button and re-solder it to the new cable. This saves you having to feed the cable through again.