I calibrate before every bike ride.

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Zero off-set on race morning. If there is a big temp swing, you can always rezero your Riken by pedaling backwards 4 times once you get rolling.

So do you wait for the calibration to finish at T1? Do you do it while running to the mounting line?

I calibrate before I go to swim start.

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Calibrate? No.

Zero the offset? Yes.

(There's a difference, despite Garmin's misuse of the term "calibrate")

"Zero early, and zero often"...and with your Riken, you can zero anytime while you're riding just by backwards pedaling while coasting :-)

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I wasn't aware backpedaling does the zero-offset. Thank you all for the info!

I'd consider them both forms of calibration. In both cases a parameter is being calculated based on comparison of a measurement to a known quantity. One is a zero offset calibration, another is slope calibration.

Yeah, just make sure you backpedal at least 5 times to ensure a complete zeroing (there are apparently 4 memory registers that are averaged for the zero calculation, and one register is overwritten in each backwards cycle). The backwards pedaling zero isn't as potentially accurate as doing a static, manual zero through the head unit (since it makes an assumption about drivetrain friction), but as long as your drivetrain is in well-maintained shape, it seems to do fairly well.

Sometimes, if I'm curious if the zero may have drifted on one of my Quarqs, I'll just look to see if the output drops to zero as I soft-pedal forwards while coasting. That's an easy "in situ" check you can make while riding...

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I think of it more as a power meter is basically a fancy mobile weight scale. Setting the zero, or tare, is easy to do and check. Making sure its output is "calibrated", takes more time and a series of loads. Complete calibration requires BOTH. To call zeroing "calibration" is being incomplete.

Garmin could have used the term "tare", or "zero" instead of calibrate for the offset zeroing process. That would have saved a TON of confusion when people are asked if they are using a calibrated PM, and many answer "Sure, I calibrate it before every ride" :-/

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I agree that would clarify the terminology used by users.