Instinct 2 with Edge 840 bike riding?

You don't need to record activity on your watch and on Edge. As long as Edge 840 is recording and true up is enabled in settings on both Edge and Instinct 2, you'll be ok. Instinct 2 will pick up your Edge statistics after activity is synced to Garmin Connect. In fact, using Instinct 2 for bike activities is not a good idea because the elevation data will be crap, since it's lacking maps.

elevation data comes from the barometer so it wont be crap. my instinct 2x have really good elevation data

Sorry but no barometer/gps data can be as accurate as topo maps. If you don't care about this that's fine but in more undulating and mountainous terrain these differences add up to significant variances which make the elevation data useless for more serious statistics. I'm talking from first hand experience.

during activity it only uses barometer. only starting point it calibrates with GPS and DEM. Instinct have DEM to and it will calibrate when you start activity.

"during activity it only uses barometer" - that's precisely the problem which leads to poor accuracy.

that was not the question. both instinct and 840 calcutes elevation the same way.

picture attached was from 840 manual

DURING ACTIVITY Edge takes elevation data from maps not from baro.

ok. can you link where you did found that?

Where I found what? That Edge uses maps for elevation? How do you think it produces the gradients?

that it takes map data instead of barometer of course!

if you load a course it will show you gradients but when you finnish eleveation data wont be the same as the course. that i beacuse it takes barometer data instead.

What if you ride on a bridge or cliff gps data is not that perfect and maybe gps point is 2 meters outside the bridge, then you would have really bad elevation gain

manuel never says anything about map altitude. only barometer

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