Please review files and assist me on getting things right

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naavt
Posts: 38
Joined: Wed May 30, 2018 7:40 am

Please review files and assist me on getting things right

Post by naavt »

Hi,

I've sent and email in Velocomp's webpage but had no feedback yet, so I'm posting my issues here:

I’ve just ended another ride with my new PowerPod and data is all over the place, again!,

At the beginning of this month I've received my unit and went out to make the Cal Ride which I'm sending to you (attached). This file has a 2017 date and I can't find out why. It's not that important but since we're here, can you please explain me why's that?

Now the important stuff:

Mounted the PP on my new K-Edge combo mount (Wahoo Bolt/GoPro) securely. Calibration went fine (or so it seemed), but after calibration the first thing I've noticed was a speed issue, with over the top real speed. Went ahead to try the PP and done a hilly section near my home. I top around 60 kph descending that section in a good day, but my Bolt was showing 100 after the iCal Ride!

Climbing had the same effect with misread instant speeds, and when braking to a stop it read 10 kph when I was almost stopped, taking a few seconds for it to read 0 kph after a stop.

So yesterday I went for a new ride and unfortunately issues with speed remained, albeit less significants. I can see in Isaac that my max speed for that ride was 55.2 kph, whereas Strava shows 60,5 and my Bolt states 145,7 kph!!! Well, I wish, but my Bolt is certainly the wronger here.

Nonetheless, is very annoying to read such a thing when you're riding, and have a record like that in my Wahoo Companion App, the one that's linked to TrainingPeaks, forcing me to change stats inside TP in every ride.

Besides all that, I've planned a route around an elevation of 900m and, to my surprise, I've ended the ride with my Bolt stating around 670m. I've found that very odd so I went to correct that automatically within Strava. It corrected the elevation to 912m which is undoubtedly more accurate, so I suspect that something's off with PP altimeter?

I’ve attached 2 files. One for the Cal Ride and one for my last ride. I can send an exported gpx of that ride from Strava for you to compare if you'd like.

I can't say I'm not thrilled to have a power meter outside my turbo trainer for the first time. I only wish I could rely on it to give me accurate results. I've read a lot about PP compatibility with Wahoo Bolt (including on this forum), before buying, so I was under the impression that everything should work out together, but it isn't.

If you can assist me on this issues I’ll be very appreciated, since everything was working perfectly before PP's introduction in this equation.

Thanks!
Attachments
iBike_11_15_2017_0026_4_km_CalRide.ibr
(39.16 KiB) Downloaded 195 times
iBike_06_13_2018_1050_128_km.ibr
(967.31 KiB) Downloaded 188 times
Velocomp
Velocomp CEO
Posts: 7793
Joined: Fri Jan 11, 2008 8:43 am

Re: Please review files and assist me on getting things right

Post by Velocomp »

The issues here are with your Bolt, not with PP.

PP transmits power data to Bolt. Your Bolt receives power data from PP, and speed and cadence data from your other sensors.

So, if the issues are with speed, the problem is how your Bolt is processing speed sensor data. This is not a PowerPod problem.

Why your Bolt is misbehaving I do not know. One thing that you can check is to make sure Bolt is paired in ANT+ mode, not BLE mode.

The reason your cal ride had a 2017 date is because your ride was done before you connected your PP to Isaac. Isaac sets the date and time of PP. Another possibility is that you did a hard reset of the unit. After a hard reset you need to reconnect to Isaac to restore the date/time.

Strava uses GPS speed for its calculations. I would trust the Isaac reading.
John Hamann
naavt
Posts: 38
Joined: Wed May 30, 2018 7:40 am

Re: Please review files and assist me on getting things right

Post by naavt »

Thanks a lot for the quick reply!

I’ve read the Bolt instructions and it’s paired trough BLE. I have no opportunity to test it this weekend but I’ll paired it trough ANT+ has you suggest and give it a try next Monday.

Regarding Elevation. I don’t see total elevation stats on Isaac. Only the highest altitude and maximum grade. Can you confirm on my 128km ride that PP registered a total elevation around 900m?

If yes, is it my Bolt again doing the wrong math? Again,it never happened before. Ca it be due to the same pairing issue?

Thanks!
Velocomp
Velocomp CEO
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Joined: Fri Jan 11, 2008 8:43 am

Re: Please review files and assist me on getting things right

Post by Velocomp »

Make sure you're looking at the advanced stats view in Isaac.

Isaac shows you gained a total of 662m on your ride.
Attachments
Screen Shot 2018-06-15 at 6.38.07 PM.png
Screen Shot 2018-06-15 at 6.38.07 PM.png (66.9 KiB) Viewed 6405 times
John Hamann
naavt
Posts: 38
Joined: Wed May 30, 2018 7:40 am

Re: Please review files and assist me on getting things right

Post by naavt »

Velocomp wrote: Fri Jun 15, 2018 6:39 pm Make sure you're looking at the advanced stats view in Isaac.

Isaac shows you gained a total of 662m on your ride.
Advanced stats. Thanks for the tip.

About gained elevation, that’s way off, hence my question on how it is measured. I can send you a Ride With GPS file with that route for you to confirm that elevation is around 900m.

Strava corrected it automatically to 912m. What can be wrong for PP to register such a different elevation gain?
Velocomp
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Re: Please review files and assist me on getting things right

Post by Velocomp »

I don't trust Stava elevation data at all. Strava uses maps to guess at elevation climbed information; we use actual on-the-bike measurement.

As an example of the kind of errors Strava produces: I live in south Florida, where it is EXTREMELY flat.

On June 2 I did a 9 mile ride ride, where my PP showed I gained about 72 feet (there are two short, 2% bumps; the rest is nearly flat) . Strava showed 161 feet gained for the same ride, over 2x the amount. The Strava guess is ridiculous. My consistent experience is that Strava overestimates elevation gained.
John Hamann
naavt
Posts: 38
Joined: Wed May 30, 2018 7:40 am

Re: Please review files and assist me on getting things right

Post by naavt »

Velocomp wrote: Sat Jun 16, 2018 12:51 pm its don't trust Stava elevation data at all. Strava uses maps to guess at elevation climbed information; we use actual on-the-bike measurement.

As an example of the kind of errors Strava produces: I live in south Florida, where it is EXTREMELY flat.

On June 2 I did a 9 mile ride ride, where my PP showed I gained about 72 feet (there are two short, 2% bumps; the rest is nearly flat) . Strava showed 161 feet gained for the same ride, over 2x the amount. The Strava guess is ridiculous. My consistent experience is that Strava overestimates elevation gained.
I understand that GPS elevation isn’t the most accurate as you say, but I’ve only resorted to Strava elevation estimation since I’ve found an enormous discrepancy between my past rides on this route and this one.

Past rides were done with Wahoo Bolt alone that has a barometric altimeter, and data from it for the same route always showed a bigger elevation than 600m climbed for this route.

I’m only concerned about this because it’s a 300m difference. That’s a third difference!
Velocomp
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Re: Please review files and assist me on getting things right

Post by Velocomp »

I really don't have anything extra to add to this.

GPS elevation is inherently inaccurate.

Strava uses maps and, maybe, GPS information. More guessing.

We use baro sensor data.

The thing to do is to pick your preferred way of getting the data, then stick with it. Consistency is sometimes more important than absolute accuracy.
John Hamann
naavt
Posts: 38
Joined: Wed May 30, 2018 7:40 am

Re: Please review files and assist me on getting things right

Post by naavt »

Velocomp wrote: Sat Jun 16, 2018 2:19 pm

The thing to do is to pick your preferred way of getting the data, then stick with it. Consistency is sometimes more important than absolute accuracy.
That’s true. Thanks anyway for your insights on this matter.
naavt
Posts: 38
Joined: Wed May 30, 2018 7:40 am

Re: Please review files and assist me on getting things right

Post by naavt »

Velocomp wrote: Sat Jun 16, 2018 2:19 pm I really don't have anything extra to add to this.

GPS elevation is inherently inaccurate.
I'm astonished by how much I was misinformed about all this elevation stuff. Been reading a lot about it after your insight on this matter and it's incredible how I and other fellow riders were mislead all this time about Strava elevation stats. Somehow is frustrating to finally understand that all my elevation data is some kind of a fraud. Many are asking Strava to look into it and I feel the same.

Once again, thanks for the insight.

I take this opportunity to send you another iCal file, since I've rotated the mount a bit and changed my Wahoo speed sensor for a Gamin one.

Regarding the levelling of the unit, I have a combo mount and for my Bolt to stay levelled, PP has to ride with a 4,5 degree upward angle. The combo mount won't let PP to rotate, so it's a levelled PP and a downward Bolt, or a levelled Bolt with a slight upward PP. Do you think that it will compromise PP's accuracy?

I've bought Garmin's sensor after reading one post of yours, were you've mention that it works better than Wahoo's. I think I'm obtaining slightly better power figures after my iCal today and that's the reason why I'm sending the file for you to see if I've done everything right.

I've noticed that the previous profile was created with a wrong wheel circumference. It's now manually entered with 2105 (700x25), even if I ride tubeless tires and don't really know if that circumference is comparable to clinchers. Previously that data was submitted automatically by the Wahoo's Companion App and the circumference was slightly shorter (don't know if that can affect the power numbers or not).

Isaac doesn't allow for tubeless tires on profiles page. Do you think that picking clinchers is the best option for profiling a tubeless tire, or do you recommend any other setup?

Thanks!
Attachments
iBike_06_22_2018_1032_5_km_CalRide.ibr
(43.58 KiB) Downloaded 174 times
Velocomp
Velocomp CEO
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Re: Please review files and assist me on getting things right

Post by Velocomp »

Please post a ride file after you did your cal ride.

You should be OK with the slight change in wheel circumference.

Clinchers is a good choice.
John Hamann
naavt
Posts: 38
Joined: Wed May 30, 2018 7:40 am

Re: Please review files and assist me on getting things right

Post by naavt »

Velocomp wrote: Fri Jun 22, 2018 1:11 pm Please post a ride file after you did your cal ride.

You should be OK with the slight change in wheel circumference.

Clinchers is a good choice.
Don't know if it will be enough for you to draw any conclusion since it was a mere back home ride (after iCal), doing only recovery work, but here it goes.
Attachments
iBike_06_22_2018_1131_4_km.ibr
(43.7 KiB) Downloaded 182 times
Velocomp
Velocomp CEO
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Re: Please review files and assist me on getting things right

Post by Velocomp »

Actually, it's plenty; looks great!
John Hamann
naavt
Posts: 38
Joined: Wed May 30, 2018 7:40 am

Re: Please review files and assist me on getting things right

Post by naavt »

Velocomp wrote: Fri Jun 22, 2018 3:29 pm Actually, it's plenty; looks great!
Thanks a lot ;)

By the way, do you have any plans to implement a way to check PP battery on Wahoo Bolt as you did on Garmin units?

Cheers
Velocomp
Velocomp CEO
Posts: 7793
Joined: Fri Jan 11, 2008 8:43 am

Re: Please review files and assist me on getting things right

Post by Velocomp »

We follow the standard ANT protocol for battery level. So, I would check your Bolt instructions.
John Hamann
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