Garmin Rally power meter pedals calibration

Broke some personal power records yesterday, but I didn’t calibrate the pedals before I started. Anyone have an idea how much difference this will make? Are we talking 30W? 100W?

Impossible question to answer, even if you had given more information.
Provided that they are working correctly, torqued down properly, were calibrated for your prior ride, and enviro/riding conditions were similar… not much at all.

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Ok so a bit more info:

Only recently got the power pedals (a few weeks ago). Have had a Power2Max power meter on the roadie since January - it calibrates itself any time I stop pedalling and has proved to be pretty consistent. Have been doing a lot more MTB riding over the past few months so my power data from the roadie and trainer (I use the Power2Max data on the trainer) is minimal during that time. I use Intervals.icu for all my data. Have not done any max efforts on the roadie for a while. So the estimates for my FTP on intervals.icu have been going down gradually when in fact it’s likely to have gone up based on what I’ve been seeing with my heart rate and times for various segments (including 3 KOMs the previous week). After yesterday’s ride the machine learning at intervals.icu says it’s estimate for my FTP is +102W on what it previously thought. I have no doubt it has increased and yesterday’s efforts were after only a single 90min ride last week so I was very fresh. I’m not naive enough to think I’ve increased my FTP by a legit 102W in the last few months though lol.

Yesterday the power meter said I did 8min @ ~424W. I was watching it during this climb and it felt like at least a mid-high 300s effort and I figured I would start to fade at 4-5min but my legs said “nope, I’m happy let’s keep going at this effort”.

I’ve gather the Garmin Rally pedals are fairly sensitive to being torqued properly (which isn’t easy since they don’t take a hex key, you need to use an old fashioned pedal wrench). I just order things to be able to torque mine properly. I too I am seeing numbers that I would like to believe, but just can’t wrap my head around them. They appear to be about 50 watts high.

While there are many factors that could have affected your power readings in the moment, You can at least verify the pedals are reporting correct torque values by following the procedure in the link below.
https://support.garmin.com/en-CA/?faq=AVZeQisZvi3oBYZUUZdPV6

Either way, sounds like it’s time to calibrate and go out and smash a couple 8min intervals at 424W…

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I recently bought the RS200 version to use when travelling or using other bikes than my own. Matching data against my other power meters (Kickr Bike, S-Works/4iiii and Shimano DA Power), it seems the Rally pedals report consistently 1-3% lower power than the other powermeters on the same rides (15-30 min long climbs). I have made sure to calibrate the powermeters before each repeat, so that should not be an issue, and give that the differences seem consistent, who knows which one is most reliable - the numbers are valid enough for me to be happy.

But in regards to calibrating Rally: does it matter if the bike is slightly tilting towards either side during the calibration process? Or is it better to stand the bike against a wall or some other object and ensure that the pedals are as straight as possible before calibrating?