Post by Johannes Gießibl

A Japanese customer explained their overload requirement for an eBike torque sensor. 600 Nm. The sensor must not break or change its characteristics. I asked what scenario they were designing for. A cyclist riding at 25 km/h hits a Bordstein - a kerb - with the pedal at full speed. The impact torque travels instantly through the crank, through the bottom bracket, into the torque sensor. 600 Nm in a fraction of a millisecond. I said: you are worried about the sensor shaft. He looked at me. I am actually worried about the bicycle rider. He smiled. Both need to survive, he said. In Europe the overload requirement for eBike and mountain bike torque sensors is approximately 340 Nm, derived from ISO 4210 standardised lab test procedures. Defined scenarios, reproducible results, documented methodology. In Japan the requirement is 600 Nm. Because someone asked what actually happens in the real world when a cyclist hits a kerb at full speed. Same sensor technology. Same measurement range. Completely different overload requirement. The standard defines what you test. The market defines what you survive. Nobody in Europe has hit a kerb at 25 km/h with their pedal and thought: I wonder if the torque sensor is okay. In Japan, someone did.