First Ride with Power Meter
Fair warning...I like data.
I installed a Stages power meter last night and took my first ride with it this morning. I'd often wondered how accurate Strava estimates were. Turns out, probably not very accurate. The ride this morning was only 20 miles. I recorded the ride in Strava on my iPhone (without the power meter) and on my Wahoo Elemnt Bolt with the power meter so I could compare. The data was depressing, encouraging, enlightening and interesting all at the same time.
To start with, Strava's estimates aren't too accurate. I'd read folks estimate their results were within 7-10%. That was nowhere near the case with me. My ride had 15 Strava segments. Only on one segment did Strava and the power meter agree and this was the longest segment of them all at 3.2 miles.
Strava estimated more power than the power meter on three segments. Interestingly two of the segments were back to back. One a max effort on a short climb (481 Watts vs. 527 watts) and the next was a short downhill segment where I was so wiped out that I didn't even peddle much (59 watts vs. 89 watts). So Strava read 9% high on the up hill segment, and 50% high on the down hill segment. On the third segment, 162 watts vs. 169 watts, or 104%.
On all the other segments, the power meter read higher than Strava. Between 111% and 195% high. That seems like an awfully wide margin. Interestingly, if I throw out the first four segments of the ride, the range is between 111% and 128%.
The depressing: when the legs start to hurt and I back off a bit, the power number is, um...unimpressive. Also unimpressive are long down hills, even when moving pretty quickly.
The encouraging: if the meter is correct, my weighted average power for this ride was higher than what I was expecting, at 190 watts, over 1 hour and 24 minutes.
The enlightening: it's interesting to put a label on various pain levels. Going up hill vs down hill, regardless of speed, you quickly learn what 250, 300, 400 and 500 watts feels like. I now know that 400 watts requires some serious attention and 500 watts starts to hurt pretty quickly. I also learned that I put out 749 watts at some point this morning...for a couple of seconds.
I need to do an FTP test now. Maybe I can get that done Sunday morning.
-Matt