AeroPod, PowerPod and Newton

Hi Velocomp,

First of all thanks for this powerpod v3, great first rides and good installation instructions (and nice, the powerstroke feature). I've mounted and calibrated the pod with a short O&B. After a 38 mile longer O&B ride, I started to play with isaac's Check Calibration, see attached original ibr and screenshot. Check Calibration suggests to increase Aero and Windscaling up to ~3.5, see screenshot; I see the avg speed and windspeed get closer (there was not that much wind, about 3 m/h E, but a bit varying), but I am not sure whether I should update the settings, since the windplots look already reasonable with the original calibration settings (?). Hence a few questions (bike is Trek Checkpoint ALR5 700x38c Schwalbe gravel G-One, with fenders, racks, 2 750 ml water bottles, winter outfit, I guess total about 14kg-15kg, plus my weight about 80kg at 2m height, 61cm frame):
- What is the definition of wind speed? Is it the wind measured by the pod?
- What do the aero and windscaling settings do?
- What are reasonable values for Aero and Wind scaling? (I see big differences on the forum, hence a sanity check for the numbers would be helpful)
- The ride was an O&B, but at the start there was still an extra piece. I see isaac corrects for this by indicating start and end of O&B, so I assume this is ok?
- What would you suggest to do: update to suggested values or keep as-is?
- If I use the Analyze Route option, I get speed and windspeed exactly equal, but then it is not clear to me how aero and windscaling are adjusted and how I could save the associated updated calibration -- how can I find those in that scenario?
- In fact I went ahead and updated the calibration as suggested by Check Calibration. I went for a short ride with several steep climbs, see also attached. Initially I thought the power was overestimated on the climbs, but after careful trimming of segments and comparing to rides on a better bike (Emonda SL7 with 25mm Conti GP, summer outfit) with direct powermeter (stages) and http://www.wolfgang-menn.de/powerhill.htm, in fact I believe values are rather accurate (as expected). What do you advise: revert to original calibration settings with lower aero/wind scaling or keep the updated settings (with significantly higher windscaling factor)?
- When transitioning seasons, do you suggest to update the weights in the calibration?
- Any other things in the calibration that should be checked and/or look strange?

Thanks,

Joost

Lots of questions!

First, let me say that your 12/8 ride file is a nice example of a perfectly calibrated PowerPod! You were riding in a calm wind, and your wind speed is nearly identical to your bike speed.

Your PowerStroke is excellent, too; you have a very economical stroke, indicating that you pedal very smoothly on the bike.
Now, to answer all your questions:

1) I would continue to use the wind calibration of your 12/8 ride.
2) Wind speed is measured by the wind port. The value is the total wind opposing you as you ride the bike. It is the sum of ground wind speed and bike speed (when you ride a bike with zero ground wind, the value of the wind you feel is the same as your bike speed).
3) "aero" and "wind scaling" are factors calculated during the cal ride that cause average wind speed to be equal to average bike speed over the course of the cal ride.
4) The value of wind scaling depends on the location of your device on your bike. There is no "standard" value, so there is no reason to compare your value to others. When you look at your ride files, if in calm winds your wind speed is close to your bike speed then your wind scaling factor, whatever it is, is correct.
5) Analyze Route does correct problems with wind speed, but you can't save the correction. You were correct to use the Check Calibration feature, which does allow you to update the profile with the corrected wind scaling factor.
6) Stick with the profile from your 12/8 ride...you have really dialed-in things!
7) Unless your weight changes significantly, I would not change the weight setting in your profile.

Many thanks for the detailed response and explanation, John. I'll continue to use the 12/8 calibration. I did a mixed hill/flat ride (calm wind, some bursts) with it today again and compared afterwards by switching the profile to the original calibration of 12/6, and with your explanation indeed 12/8 looks better (avg windspeed and bike speed closer than with 12/6 cal). Watts vs heart beats also match closely with recent comparable rides. Powerstroke didn't look as nice as the 12/8, but still ok at 3W / yellow box and also expected as it was a much heavier ride (and I just found out you can actually do the powerstroke analysis for a selection of the ride, nice, looks like I have uphill wobbling to work on!). Thanks again, great to have such support via this forum, very glad to have now also reliable power measurements on my winter/gravel bike! Best, Joost