Odd values (on 2 bikes) - must be doing something wrong

[Scaredypants]

Hi, I'm new to this forum so apologies if I'm in the wrong section or anything

I use a powerpod with a garmin 810 and garmin speed & cadence sensors (2 bikes, road & TT, with 2 different sets of sensors)Both bikes have had a best accuracy ride done and I've since been looking at the check accuracy function after out&back rides.
TT bike has pod under base bar (though initially was an out-front mount before I deleted profiles & started again). Road bike out front but has also been under the bars.

My problem is that power seems exaggerated when climbing and a little low when flat or descending, on both bikes. I don't have a direct power meter on either bike but I turbo on a supposedly very accurate machine and so think I have a reasonable feel on perceived effort. More than that, though, I get very odd numbers whenever I go out on rides after initial setup

When I try the check accuracy function after shortish rides on quite still days I get large changes being proposed by Isaac, including things like wind scaling over 3.5, which sounds very high from what I've read on here. I've deleted all profiles & repeated setup a couple of times but get the same thing happening

I will add that the roads I ride on are pretty variable surface and bumpy enough to have the pod read low or even zero on several stretches of any ride, though well under 5% of an entire ride (this is why I've changed around the mounts, to see if that helps but I don't think it alters the frequency of this happening)

Can "dropouts" make so much difference to the algorithm that my profiles go so far from the norm ?
Should I scrap the idea of checking accuracy and just delete, then rerun the best accuracy on a known smoother stretch, then never touch the software again ?

Thanks,
Mike

[Velocomp]

Please post .ibr ride files illustrating your concerns.

We will help you figure this out!

[Scaredypants]

Hi John, thanks

Road bike files initial calibration ride, plus yesterday's ride attached

[Velocomp]

Two things:

1) Your PP is recalibrating itself during the first 8 minutes of the ride

2) You are riding in some FIERCE head and tail winds at the top of your climb.

Please post a photo showing where your PP is mounted on your bike. Front and side views would be helpful.

[Scaredypants]

Thanks John

1) Recalibrating because I swap from one bike to the other ? (it reads zero watts initially - is that while it's recalibrating?)

2) Regarding wind, if you mean the longer ride on 9th July, it was 6-8 mph according to windytv, no gusting. Felt less than that, almost still

Pics attached I hope
(bar area is fairly "busy", I admit but everything's well behind the "mouth" of the pod which is pretty much level with the brake levers)
Garmin sits on top of the PPod mount

[Scaredypants]

err, pics this time, too !

[Scaredypants]

thinking about your comments regarding wind - my ride invovled a fairly steady climb up to a plateau where I did some pretty hard short sprints with quite low effort in-between - might that be what you're interpreting as high winds ?

[Velocomp]

Your ride file shows strong--and symmetrical--winds on the plateau.

If correct this would be anything but a calm wind day...

You can see this in the screen shot of your ride.

Your PP mount location looks fine, though I don't recognize the mount. Is it made of plastic?

[Scaredypants]

Honestly, wind was nowhere near that - I've attached a screenshot from (http://www.ogimet.com/gsynres.phtml.en) that shows historic wind data for an airstrip 10 miles from my ride site. You can see they also are reporting the 11am wind on Jul 9th as 6mpg, no gusting

I guess I'll delete profiles & start over, just to see what happens - do you think ?

Mount is plastic but really quite rigid, and I had much the same experience with a metal mount directly under the bars

Also, maybe relevant
- the plateau where I did the sprints is almost straight and lagely East-West, so the wind ought to have been mainly a sidewind
- WHen doing my bigger sprints I doubled back on the road and so went West, East, West, East

[Velocomp]

Hmm...please do a new O&B cal ride, then a ride afterwards. Please post the ride file.

[Scaredypants]

Hello John,
I did just that yesterday, so here we go:
(my calibration ride started with very slow riding as my gamin had reset itself to stop showing a power window so first 100 yards was coasting while setting up windows - would that matter?)

Wind was negligible, 2-4 mph I'd say

(I took a look; mount is a garmin out-front with an additional PPod mount fixed underneath (bolted on, not a sticky pad))

[Velocomp]

This looks much, much better. I think you're good to go now.

[Scaredypants]

Great, thanks - so I ignore any future "options" from coming rides and just stick with this profile ?

[Velocomp]

Stick with this one, and post your next ride if you like.