Torques: Rear wheel axle and TMM sensor

Support problems - where do they come from?

Many customer feedbacks complain about support problems with the Stromer, which are often caused by the tightening torques of the thru axle and the torque sensor plate. Only the correct setting for the specific model and subsequent calibration allow the typical Stromer riding pleasure to emerge.

As I explained in the topic 'Functional principle' the TMM sensor is actually a force sensor and not a torque sensor. It measures the force exerted on the chain/belt by pedaling. The measured force is directly proportional to the torque on the bottom bracket which is generated by pedaling.

In everyday use, the term torque sensor has become commonplace. This is also the case when talking about the tightening torques of the rear wheel axle and the sensor plate.

Both have a decisive influence on the support regulation of the hub motor. If something is wrong here, this is immediately noticeable in the assistance.

Torques of the rear wheel axle 

I have explained how to solve support problems in the chapter 'Problems with support and possible solutions' described. Here is an excerpt from the torque table. The compilation comes from officially accessible sources such as Stromer operating manuals, forums, FB groups etc. and is without guarantee.

* Assembly sequence / setting
ST2/ST3 Pinion: First tighten the axle, then the sensor plate!
Pinion belt opening: secure 10 Nm with Loctite 243

If support is too agile: reduce torque to approx. 30 Nm
ST7 axles: front and rear axle both with 10mm Allen key