Device Sample Rate Issues

Hey Folks,

I was comparing myself to my buddy on a short climb that we took very easy on a Sunday ride and I couldn’t help but notice what seems to be different kinds of smoothing across all fields over the different devices - I am using a Wahoo BOLT and he is using a Garmin Edge 830 - it’s pretty noticeable on the power readings but even more so on the gradient with the BOLT looking very wrong. Has anyone else experienced this? Is it a settings or a device issue?

My data on the left my friends on the right.

Does your friend also get activities into from Strava? It is possible that Strava is adjusting the altitude (and hence gradient) data. I know they do that for runs on devices without a barometric altitude sensor.

Your friends power looks a bit noisier but you both end up on more or less the same number.

Other than the 30s power trace only smooths power if there are very many more data points than pixels. So if you have 4000 points on a ride and 1000 pixels on the display it will smooth 4 to 1. As soon as you zoom in you will get the raw data.

Are both devices set to record every second?
From the picture, I would think that the Garmin is set to “every second”. I don’t know if the Bolt has a similar setting as the “Smart” recording on the Edge.

To my eye it does look like a sampling rate thing, I can’t find any settings to change it or make it more granular. It’s not necessarily an issue just an observation more than anything.

As @david said the intervals come out more or less the same which itself is interesting but for other reasons mostly around that our FTP’s and weights are different but our power output and average speed on the same interval are nearly identical. Not looking at HR data as our hearts rev very differently.

@david both are from Strava into ICU but I see that the Bolt kind of “flattens” the gradient data and likely the other data too. I’ve never looked directly at the .FIT files so haven’t checked the granularity of the logging to the file.

@david as an aside, do you have plans to have a “show raw data” button for selected intervals? Something like a table for each data field with the logged value?

If this is available already I’ve not stumbled on it yet.

The reason I ask is for comparison sake. I find it hard to match selections to each other easily whereas if I could view it in a table and match the time stamps that would be useful.

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Which data points are you looking for? You can see interval data in tabular form on the activity /data page.