AeroPod, PowerPod and Newton

Rode using the iAero this evening when I got home. It was windy cool and rainy. I was a little disappointed in my results with the iAero, and wondering if anyone had any suggestions.

First, this was my TT bike which I recently just set up. I sent my cal ride data in and was told it was a really good cal. Before riding, I did a good wind offset. I then rode from my house down to the beach, about 18 mins. Along the way, I observed that my W readings were much higher than I usually see on that same stretch of the ride (this is one of my stock rides). Got to the beach and began my interval (at about 18:40 on the ride). It was a 6 min interval and I was attempting to keep my Watts at my FTP (about 221, measured on a PT a week ago). As you can see for that 6 min interval, I was holding an avg of 272W but my HR was spot on what it should have been at 221W.

Did a short rest interval then another 6 min interval starting at around 26:40 and ending around 35:00). Unfortunately, I had some twists and turns during this interval, so not as easy to hold good watts. Again, my Watts were higher than expected (229W/148 HR). The watts were lower thanks to some coasting around corners and turns.

Also, it began raining and my watts dropped off from 49:30 to about 57:00 then magically began working again.

I’m sure that the latter problem may have been weather related? Any ideas or suggestions?

Attached the CSV file to see if anyone has any suggestions.

Your Crr is too high; for asphalt roads it should be around 0.004, not the 0.008 in your ride.

Tweak your Crr to 0.004 in iB3 and you'll see the results you expected.

You can see where rain filled your wind sensor port between minutes 47 and 57. You can remove the iBike blow the wind out of the port, then resume.

Thanks John.

I fixed the Crr as suggested. This Crr was from my cal ride I did on Sunday, so unsure as to why the Crr was so high.

After fixing the Crr I reanalyzed the file and I came up with 264 avg power for the first int and 218 for the second int. I think the first int is a bit on the high side, perhaps 25-30W high. I think the second int is also a bit on the high side, but not as much. I think that int is around 10-15W off. However, this is only the first ride and I am basing those #s off of an FTP test done on a trainer with a power tap. It would most likely be worth my while to perform another FTP test using the iAero to see what kind of numbers I get.

About the rain: yes, when I started getting wacky wattage numbers, I immediately pulled over, shook out the iAero and remounted it. Started getting better numbers after that.

Do you think I should do another cal ride?