Torque Value is jumping after calibration

I have a brand new pair of dual-sided Vector 3 Pedals. I am using them with my Fenix 6x Pro.

I used to have a Powertap C1 Powermeter and after each Calibration I got a static Torque value displayed after calibration; most of the times it was shown to have 0.00 Torque offset.

However, after each calibration of my Vector 3 I get a Torque-value after successful calibration, which is never static, but that value is constantly changing. Most times the showing values are between +/-0.2. Is that normal? Why are the values constantly changing even though the calibration was performed and nothing is being moved on the bike. Are my pedals flawed?

Thank you for your help.

0 t_smit over 4 years ago

This is normal operation. The torque value that is shown is a real-time output of the applied load to the pedal. This is so that you can do a torque slope calibration by hanging a known load off the pedal.

0 alex11 over 4 years ago in reply to t_smit

Thank you VERY much for the quick reply. Just a suggestion: You could write that feature, i.e. behaviour in the owner's manual, so that new Vector customers don't get insecure if they are used a different Calibration behaviour.

0 Cugar over 4 years ago in reply to t_smit

I'd like to ask here again for this behavior. The question is specific to the fluctuation - and not to the output itself.

To be precise: I'm using the 'Calibration' feature on my Edge1030. Calibration is shown to be successful and the torque is displayed - which is what is expected in this mode.

Now, cranks are horizontal and there is NO load on them - all is static!

Despite this, there are torque fluctuation between +/- 0.3 Nm.

Doing a torque test with a weight, fluctuations in the same range can be observed.

If this is the case, why even going through the pain of applying a weight with good accuracy?

0 VeloManR over 4 years ago in reply to Cugar

It is the nature of the various devices we call “sensors.”

This term applies to any device that turns a physical parameter (light, sound, acceleration, rotation etc.) into a “signal.” A signal is some quantitative representation of the physical parameter being sensed.

The signal is numeric, whether discrete (a.k.a. “digital”) or continuous (“analog”). Whenever this sort of technology is employed, there are inaccuracies (they are truly inevitable). These inaccuracies have both systemic (predictable or computable) and a stochastic (random) components.

When you run the Vector calibration (under the assumption that the pedals are unloaded), it looks at a bunch of the “raw” or “uncorrected” or, more to the point, “uncalibrated” sensor data and it says “average is 1265” and calls that “zero applied force.” Now, as it sits there, it’s receiving ongoing sensor inputs. And they all exhibit the random inaccuracies.

And it’s those random “fluctuations” that you are seeing in the endlessly changing calibration display.

0 OlekM over 3 years ago

Hi, I have the same issue. I'm using Vector 3 for about 2 years. At the beginning (about 1 - 2 years ago) there was no such issue. Torque value has been static and equal zero without any fluctuations. I have noticed the change in this behavior after (I think so) Vectors latest firmware update (ca. few months ago).

BTW: The question is how to do the torque test with a weight described by Garmin (to precisely set power meters scale factors). If it's changing and fluctuating from minus to plus there is no way to get the right numbers from the test and calculate correct scale factor.

0 aweatherall over 3 years ago in reply to OlekM

You are seeing a small fluctuation in value under a minimal load condition. When doing the toque test you are placing a much larger load on the system that make this small fluctuation insignificant.

Part of the fluctuation under minimal load conditions is due to the ANT protocol only supporting increments of 1/32 Nm. If you are on the boundary between 2 values then the value can fluctuate by 1/32 Nm.