Confused with averages again.

[SilasGreenback]

I've been tinkering with set up to try and get some sort of consistency with my Edge 1030 (4 weeks into powerpod ownership) and thought I'd got to the point where I had my edge set properly. Was getting a lot more consistent readings and less spikey power results.

Today I switched to my winter commuter due to cr4p weather and it having mudguards. Also, decided to "check calibration" as I'd only done an out and back previously on that back.

Garmin said Avg power at 193 watts. The summary ride file in ISAAC says avg 180. It felt like a ride where ISAAC said I'd average 190-200 on my other bike. Yet in the "Check calibration" ISAAC itself says analysed 194 watts so inline with garmin and the calibration puts it up to 205 watts if I accept it. I havent done as that'd put it over my garmin and not sure I believe it just yet.I did have to stop to plug a puncture so my garmin autopauses which could be part of the garmin to isaac difference it it keeps recording.

What's going on here....I can understand garmin giving a different reading but ISAAC; surely it should give me consistent results? Am i reading it wrong? Boxes on the left say avg 180 yet the calibration box says something different. see screenshot. And ridefile also attached.

At the moment I'm really not bothered about it being 250 / 150 / 50 or something else, I just want consistency. I know "garmin may do crap stuff" but the bottom line is if I'm going to train to power I need to see on screen real time and not analyse at a PC when I get back as I cant be saying "ohhh...that bit. Should a pedalled or done something different". Not sure where my readings are or what to trust at the moment.

[Velocomp]

When you ride PowerPod does two things:

1) it transmits its power readings, second-by-second, to your Garmin
2) It records the readings it's transmitting, second-by-second, in the ride file

When you download your ride, Isaac will display, second-by-second, the power readings recorded in your ride file.

Why your Garmin shows different averages from Isaac is not something I can say. I am 100% confident Isaac is correctly computing the averages it shows. Garmin has many, many ways it reports power numbers; 3 second, with zeros, without zeros, power balance...the list goes on and on.

When you do a "Check Calibration" the power numbers in your ride file might be adjusted. But this happens AFTER the ride, so there is no reason that the numbers shown on your Garmin have any relationship to the numbers in the corrected ride file. Unless you have reason to believe your device is not correctly calibrated, then don't use this function. Consistency happens when you leave the knobs alone...

[SilasGreenback]

Thanks. I can understand the garmin to isaac differences but within isaac why does the avg show 180 in the ride summary but PRE calibration at 193?

[Velocomp]

You are not using Check Calibration according to the instructions. This is not an out and back ride. It is not surprising the window is showing different numbers.

[SilasGreenback]

Yes....but i’d read somewhere that closed loop rides could be calibrated and this ride started and ended at the same place. But if its only an out and back what's the point of The calibration check on the PC? Seems easier to just do it on the bike?....but fair enough. I can learn from that.

That aside surely the starting pre calibration average should be the same regardless? Then it’d be the “calibrated power” that’d be wrong.

I dont understand why averages on the PC before anything has been done are so different. Ride file averages all the 1s readings. If the calibration is averaging something else how does it relate to the ride average and what is it averaging to get a starting point nearly 15watts higher than the ride file?

[SilasGreenback]

I’m also seeing the avg at 194 in all of the “analyse” windows too....even if i’m using the calibrate incorrectly the ride summary window isnt consistent with the other windows.

Thats the power avg thats confusing me. Is this rides avg 180 or is it 194?

[Velocomp]

I just noticed that your ride file as posted has been analyzed by Isaac; the "180" value you are seeing is a result of that processing.

To see the original data recorded by your PP, use the "Analyze/Return to Original download" command.

Original ride file is attached.

The original file has the 193W value, and you will why it is higher. At the 19 mile mark it looks like you stopped, and that your PP was bumped out of position. There are crazy-high watts for the first mile when you start riding again, after which everything returns to normal.

So, what has happened is that your Garmin is correctly reporting the 193W value, because that is the actual number recorded by your PP. But the 180 number is the correct number, because the corrected ride file gets rid of the bumped device problem at mile 19.

To get consistent results make sure you don't bump your PP during the ride

[SilasGreenback]

Cool - that makes sense. Thanks. The 19mile bump must have been my stop to fix tubeless puncture. didnt seal so had to stop and plug it. I wasn’t the most delicate whilst it Was piddling down. And once again tubeless sealant didnt seal.....but dont get me started on that one!

I wondered why the spike but dont even remember coming close to it so didnt think it’d be disturbed. Given everything set back to normal after that, Presumably it’s sorted itself out so I dont need to reset the position or anything other than just ride it?

I’m using the garmin out front with Varia mount and small gopro extender adapter so think i’ll score an alignment mark on it. The 1/4 turn varia mount makes it so much easier to switch bikes.