Bike computer (wahoo) v running watch (Garmin)

Did a 5k run using my wahoo today, and my time was quite different from my running buddy who had a Garmin running watch (not sure which one but high end).

I’ve checked my wahoo is 200 meters short on distance over 5k, so 4% out. (Not due to gps thinking I was cutting corners or anything, and it’s short so not an over estimate due to gps zig zaging around actual route).

Comparing the data, I noticed that his data appears more detailed - seems to be taking more readings. Is this a running watch v bike computer thing? wahoo v garmin?

I record my gravel rides on my Garmin 245 and Bolt, as Wahoo’s calorie count (without a power meter) is off the wall in my experience. Garmin normally records longer, but I put that down to the Bolt being paired with the speed sensor (and the watch isn’t). I’m not quite sure of my logic, on reflection…

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Interesting. I think it uses gps for distance but maybe not?

I’ve also suspected my wahoo of stealing seconds off me on shortish strava segments - but had put it down to wishful thinking

GPS is not very precise when you get down to specifics. I seem to recall that they GPS measurements can have a error range of +/- 30 ft, but I could be wrong on the number. I first came across this in my first half-marathon when the first 2 or 3 miles were bang on with the course markers and then started differing. By the end of my HM, I had a couple extra tenths of a mile vs. the course.

But the course was USATF-certified, so GPS error was the likely culprit.

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I should also add, in my case, the Garmin 245 is newer tech than my Bolt, so I would expect it to be more accurate.

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Do you have any sort of smart recording on the Wahoo (do they even have that?)? A lower sampling rate could affect your final distance measurement.

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Not sure what smart recording is? :slight_smile:

Yeah, the inaccuracies would normally be due to zig zagging (extra distance), or cutting corners (less distance). Neither the case here though - I have a couple of random drops in pace that didn’t happen in real life that seem to be the culprets but not really sure how that would happen without mostly evening themselves out over the course

Garmin has an option they call ‘smart recording’ that will have the unit record in larger time intervals when it thinks there isn’t much changing to save battery and memory. E.g. a slow uphill ride it will record every 4 seconds but on a fast downhill MTB trail it would record every second (the fastest possible). Though I’m not sure if Wahoo has something similar.

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I was seeing something similar, and apparently it’s something that Wahoo fixed with a firmware update in early June or thereabouts. My problem has gone away.

Likely due to the ‘Smart Recording’ aspect (I think that’s default for Garmin). I was running a Forerunner 945 and Wahoo ELEMNT Bolt cuncurrently for awhile on my rides and was ususally within +/-0.2 of one another for 40+ mile rides. Those differences were likely just the slight deviation in auto-pause thresholds between the two units.

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Don’t think that’ll be the case here, as it was just 5k, no stops, decent pace the whole way

Timely article on the subject…

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Back on the gravel, so no power meter, and still the Bolt reporting way more than Garmin. Garmin weight is accurate to that day (via smart scale sync), with the Bolt still set to a somewhat “aspirational” pre-covid race weight (so generally a couple of KG lower than Garmin).

Obviously with a power meter, the Bolt uses the KJ now.

Just on those gravel spins, I’ve had to re-route. Santa will probably be bringing me a Garmin 530 or 830 as re-routing on top of having to run two devices without power tipping the “can I justify an upgrade” balance.