IDbike provides various sensor systems for measuring the crank torque.

The TMM4 Sensor

The TMM4 sensor has the world's best price performance. It is a patented development of IDbike, and can be used for measuring the crank torque of the cyclist. Because of its high precision this sensor can be applied in electric bicycles as well as in power measurement systems. Here you can find is a  nice example of the application of our TMM 4 sensor

Due to the sensor’s   low profile  the rear drop out  can be designed so  that it covers the sensor completely.  This way the sensor is fully protected  and the appearance improved.


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The TMM4 sensor consists of a housing of engineering plastic, which holds a printed circuit board (pcb) , a magnet and a small set screw, which is used to calibrate the zero value

The sensor, mounted on the sensor plate, measures the deflection of the plate caused by the chain force. This, in turn calculates the pedal torque of the cyclist. The deflection is detected using Hall technology  and is maximal 0.1 mm.



The sensor is connected to the control unit with a 3 wired cable. The sensor can be hardwired or can be connected with a little connector.

The printed circuit is protected against moisture, salt and dust, by a special coating. The sensors are tested by immersion- under current - in salt water for at least one week.

And of course our sensors are tested under  extreme outdoor conditions:


foto5CO / Andreas Gutmann 



The sensor units are available in 2 versions:

  • Medium sensitivity for sportive bicycles, such as mountain bikes and speed pedelecs
  • High sensitivity for normal bikes like city and touring bicycles



TMM Sensor Unit

Supply voltage:

5 V
Output voltage: 0,1 V- 4,9 V 
Measuring range sensor unit: 120 Nm ( High sensitivity) / 300 Nm  (medium sensitivity)
Sensitivity TMM sensor unit:

 40 Nm/V (High sensitivity)/ 100 Nm/V  (medium sensitivity)

Tolerance on sensitivity: < 3 %
Allowable range ZTV (zero torque value):   0,5-2 V 
Temperature influence: < 1 mV/ ºC
Electrical disturbance: < 10 mV
Effect of moisture: < 10 mV
Operational temperature: -10 - 60 ºC
Storage temperature: -40 - 85 ºC
Durability: At least 100 million cycles
Protection Class: IP66 >> protection aigainst water and dust



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