AeroPod, PowerPod and Newton

I thought this would be interesting.

On my TT bike, I've moved the PP from the extensions to beneath the base bar (standard mount). The reason being that I want to test new arm positions and swap extensions. I rode 22 laps of my normal off-road calibration course last night and after the initial tilt adjustment, the PP reported power. The reading for power was, however much lower than I'd expect (about 140 watts) - bikecalculator would predict 200W. I've chopped off the last 11 circuits which I ran as a post-ride check calibration - it's a one mile circular circuit, and you can see that the wind/bike speed is clearly biased.

Now the odd part. When I run a Check Calibration to give a new profile, it gives me the expected 195 watts (which is the right answer). But when I try to upload this new profile to my PP, it says the tilt is -9 degrees and outside the range and won't upload.

Can you advise? I can move the PP back to the combined Garmin/Go Pro extension mount, once the new extensions are dialed in, I was just surprised at this finding.

Your PP internal slope setting so far away from correct that, when Isaac tries to fix it, you get an error message.

You should do a new, Best Accuracy calibration. This should fix things.

Thanks.

Is that for only for the post ride calibration? The original mount had some tilt due to being on the raised extensions, so I couldn't mount it level. I've the mounted pod absolutely level on the base bars now, so I'll start again with a full calibration ride when the new extensions are delivered this week. I'm right in thinking I don't have to ride both ways - Just stop on 50W and restart?

No, you should do a complete, both ways, O&B calibration.

Just a follow up for those interested. I rode an O&B calibration ride - basically three laps clockwise followed by three laps anticlockwise. Then I rode 11 laps to warm up and get a feel for target power. Finally I raced at a target power of 310 Watts per lap. Files attached for those that are interested.

Average power during the race was 312 Watts. Bikecalculator.com gives a prediction of 315 for 5% reduced Crr and 5% CdA - I'm pretty aero and run the fastest tyres ever tested on bicyclerollingresistance (Corsa Speed tubeless at 90 PSI). The race file includes an extra four laps with a different helmet at a power similar to the warm-up 11 laps, just to see if I could see much difference.

Very pleased with the results. And I won the race too

I won't be moving this Powerpod from the TT bike. I do however plan to couple it to a DFPM eventually for CdA evaluation.