Greetings from Sweden! Any friendly power guru out there with some advise? What equipment do I trust and how can I feel confident in the accuracy?
I have a Hammer H3 trainer, and a left sided Stages Ultegra crank. These are now reporting quite different numbers. Comparing the rides for the past 2 weeks, my impression is that the Stages reads around 10% lower than the Hammer H3; persisting through calibration/zero offset on both units and a hard reset of the Stages. Meaning 200W on TR is around 180 on the Stages, 300W is around 270W and so on.
Here’s a comparison between Hammer H3/TR and Stages/Garmin530 on my ramp test today (don’t mind beyond the ramp as the Garmin recording time spent vehemently panting):
My power training history is:
Wahoo Kickr Snap in October 2018 (wildly inaccurate, tightened until no wheel slip but comparing to the Stages power could differ ±80W even between consecutive calibrations)
Stages (L) in April 2020
Elite Turno in August 2020
Hammer H3 in October 2020
My impression in the autumn’20 was that both the Turno (hated the feel) and the H3 matched my Stages result (TR on a laptop, Stages on my Garmin). Having followed a training plan since October, I’m now checking in on the Stages power meter again so that I can ride within my ability outdoors.
Now this has me either confused or disappointed. During the past 6 month of training, I have seen a decent improvement in FTP (245 27-Oct, 249 today with high point of 257 at the end of Base). Burnt out a bit on mid volume halfway through Build and learnt my lesson. But mostly I have been able to spend a lot more time in each Zone which has me excited to ride outside again and continue to work on my power.
Best 20m Power outdoors (though I never went full gas for 20m) was 216w, best effort on a TR ride (Galena -1) was 241w. Riding outdoors I ended last outside season averaging 31-32kmh on 40-80km rides, and perception wise it feels like I have pushed more watts indoors than outdoors.
As both devices seemingly are consistent, what would you do in my cycling shoes? I want to enjoy riding outdoors again but I also want to trust the numbers.
- Carry on riding, recalculate my training zones, my left leg is probably just weaker?
- Distrust either device as something might be off?
- Invest in a new power meter for both legs (thinking Assioma’s or P2M) and use power match indoors instead?
I would prefer to avoid the third, I don’t print money for a living! But will bite the bullet for the best option.
Thanks to anyone who made it this far! //Michael