Ability of zeroing a separate power meter

[Bradox78]

Zero-offsetting or zeroing a power meter, is a procedure that is performed before every ride. When you do a zero-offset, the power meter zeros out any residual torque that has built up in the power meter from previous rides, temperature changes or installations. In essence, zeroing wipes the power meter clean.

I personally have a PowerTap G3 hub on the bike I ride on my Lynx trainer. Before starting the Vride software, I perform this zero-offsetting using the "IpSensorMan" app on my Android smartphone.

If this is feasible, it would be a very practical and confortable feature to have this zeroing function directly integrated in the Vride software.

[admin]

I thought that Powertaps are auto zeroing during coasting/backpedaling. I've never had mine showing non zero power during coasting.

[Bradox78]

I thought that Powertaps are auto zeroing during coasting/backpedaling. I've never had mine showing non zero power during coasting.

All PowerTap power meters (and the Garmin Vector pedals) have to be manually zeroed

Garmin recommends to do it before each ride :
https://www.youtube.com/watch?v=ZTW6HItltPU


For a PowerTap Hub using a Joule Computer :
https://www.youtube.com/watch?v=Tj9ob5p3r3Y

Same principle on a Garmin Egde computer or using a third party app on a smartphone :
https://www.youtube.com/watch?v=4UHPGT2WW-g


For PowerTap P1 pedals :

CALIBRATION AND MANUAL ZERO
Each PowerTap P1 pedal is dynamically calibrated from the factory to the highest standard. Calibration values cannot be changed by the
user. However, it is important to periodically zero the offset manually.

Before performing a manual zero unclip from the pedals and make sure there is nothing contacting either pedal. Navigate to the sensor
screen on the Joule GPS+ or other head unit and select Calibration. Initially, numbers will display related to the previous zeroing of the
calibration offset. With Manual Zero selected Press the ENTER button to zero the offset.


For PowerTap C1 chainring :

SECTION 4 - CALIBRATION AND MANUAL ZERO
Each PowerTap C1 chainring is dynamically calibrated from the factory to the highest standard. Calibration values cannot be changed by the user. However, it is important to periodically zero the offset manually.

Before performing a manual zero unclip from the pedals and make sure there is no load on the drivetrain. Navigate to the sensor screen on the Joule GPS+ and select Calibration. Initially, numbers will display related to the previous zeroing of the calibration offset. With Manual Zero selected Press the ENTER button to zero the offset. If using different brand head unit refer to the manual for specific zero offset (calibration)
instructions.

[admin]

...All PowerTap power meters (and the Garmin Vector pedals) have to be manually zeroed ...

In regards to Powertap I would rather listen to what they say. I understand that in your case we are talking about hub version of powertap. In this case as it says in Powertap blog:

"https://www.powertap.com/post/blog-15-1 ... tap-g3-hub"

"Auto-zero functionality. Temperature compensation is an important factor when measuring power in the real world. Temperatures fluctuate, and sometimes they fluctuate by a lot. The mechanism by which a cycling power meter accounts for this is crucial to your data integrity. The G3 has the same auto-zero functionality that we've been using for over a decade. The intelligence in the hub dictates that when you coast the hub knows there is zero torque, so the hub assigns a new offset value based on the new zero point. This all happens behind the scenes if you have your 'Auto-Zero' ON. Super easy."

You can also set your Garmin unit to use that Autozero function. I Myself use this functionality.

[Bradox78]

Granted but zeroing manually a power meter returns an offset value. If this returned offset value falls outside the normal offset range, this will alert the user that his power meter is in need of service. That's also why I am used to perform it.

On the other hand, pedals or cranks with power meter do require a manual zeroing because you have to unclip from the pedals since there should be no weight on them during the procedure.

Anyway, that was only a suggestion to put a small cherry on the superb Vride cake !

[admin]

Granted but zeroing manually a power meter returns an offset value. If this returned offset value falls outside the normal offset range, this will alert the user that his power meter is in need of service. That's also why I am used to perform it.

On the other hand, pedals or cranks with power meter do require a manual zeroing because you have to unclip from the pedals since there should be no weight on them during the procedure.

Anyway, that was only a suggestion to put a small cherry on the superb Vride cake !

Actually for SRM as it is crank based we do supply ability to enter offset. I have to see how much work will it be to do for PT. ... Actually I just looked. PT does not automatically send ANT+ calibration messages as does SRM when it is active but idling. I have to manually set the mode and query it. that will require new GUI and I can not reuse the already existing code for SRM. So the cherry is a bit sour now and will have ripen

[Bradox78]

So the cherry is a bit sour now and will have ripen

The Austrian Sour Cherry cake is one of my favorite, especially the one that is offered at the finish of the Glocknerkönig sportive



Anyway, thank you for having taken the time to check this