Timeline for Does changing a chainring on a e-bike requires a "firmware change"? (setting or update)
Current License: CC BY-SA 4.0
13 events
| when toggle format | what | by | license | comment | |
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| Feb 25, 2023 at 22:09 | vote | accept | Rеnаud | ||
| Feb 25, 2023 at 22:09 | answer | added | Rеnаud | timeline score: 3 | |
| Feb 21, 2023 at 12:54 | history | edited | Rеnаud | CC BY-SA 4.0 |
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| Feb 21, 2023 at 12:05 | comment | added | Chris H | @Criggie (and Renaud) if we assume the smallest sprocket, the chainring could be used to work out the maximum speed - the speed sensor on the wheel might be only for display purposes and not hooked into the motor controller | |
| Feb 21, 2023 at 8:51 | review | Close votes | |||
| Feb 26, 2023 at 3:04 | |||||
| Feb 21, 2023 at 8:51 | comment | added | Rеnаud | @nightrider if it is necessary, but it's a setting that is only accessible to authorized mechanics, it will be mentioned in a service manual (or during a training). And even without providing the answer on how to dot it, it can be useful for future readers to know whether this operation is "limited to a chainring/chain change" or a passage to a LBS is required to take care of the software side. | |
| Feb 21, 2023 at 8:38 | comment | added | nightrider | I think this cannot be answered without reverse-engineering the firmware. Everything would be just speculation, we do not know which algorithm they have implemented and how. Torque depends first of all from the gear ratio, larger chain ring with larger sprocket would give the same. But the controller may be implemented to use individual approaches for each gear, assuming its ratio, and it may figure out the current gear from speed and cadence sensors even without dedicated sensor for the gear. And we do not know if they use so sophisticated approaches or not. The speed sensor would work. | |
| Feb 21, 2023 at 8:37 | comment | added | Rеnаud | @Criggie unless the derailleur is Di2, no way to know what is the actual gear and hence infer the speed from the cadence (there is a speed sensor on the rear wheel anyway). The manual mentions tire size related to frame/mudguards clearance. | |
| Feb 21, 2023 at 8:24 | comment | added | Criggie♦ | Does the manual talk about a preferred tyre sizes? Changing them would also cause the speed calculation to be out if its done on gear choice+crank-rotations, or on wheel rotations. | |
| Feb 21, 2023 at 8:22 | history | edited | Rеnаud | CC BY-SA 4.0 |
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| Feb 20, 2023 at 20:58 | comment | added | Weiwen Ng | Hmm, this is interesting. I assume that the motor has a torque sensor to calibrate its assistance. Bicycle power meters also have torque sensors, and we only need the crankarm length as the input, not chainring size. I'm going to leave this as a comment because I don't actually know the correct answer. | |
| Feb 20, 2023 at 19:53 | history | edited | Rеnаud | CC BY-SA 4.0 |
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| Feb 20, 2023 at 19:47 | history | asked | Rеnаud | CC BY-SA 4.0 |