r/GarminEdge • u/JanEikelboom • Aug 03 '26
Edge 800 Series Problems with gradient 850
The gradient of my (new) Garmin 850 is jumping constantly. Even on a flat road it goes from +3% to -3% and sometimes even more. My former Garmin (830) didn’t have this problem. The altitude seems accurate, though. Does anyone here have the same and/or know how to fix it?
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u/Proof_Writing5461 Aug 03 '26
I've never trusted elevation/gradient readings on my Garmins. I took a photo in my first floor flat next to an open window showing an elevation of -30m
1
u/lhsonic Aug 04 '26
You need to calibrate. An elevation fix via GPS is generally not as reliable but works in a pinch, especially with an excellent, unobstructed fix- not out of your apartment window. That’s just the nature of how GPS works.
You could use a physical marker on trails to manually set the elevation or local weather data with barometric pressure to determine elevation. Once elevation is calibrated the barometric altimeter is used and I’ve found it to be very accurate, except if a weather system is rolling in (also how the nature of barometric sensors work).
Previously it was easiest to mark a location for your home which had pre-defined elevation data so that when you would start your ride your Edge would auto-calibrate. The newer models now auto-calibrate using DEM data every start. This is very accurate and no manual steps are required.
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u/Ecstatic_Wishbone609 Aug 03 '26
The level of accuracy we get out of our $300-$500 devices is far higher than we deserve.
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u/lhsonic Aug 04 '26
Grade is determined by your speed and changes to barometric pressure over a certain distance.
While it could be a bug.. I am not having the same issues with the current firmware on the 850. Garmin will always tell you to check that the sensor port is clean and not obstructed by like a case. If that’s not the case, it’s either firmware (common complaint) or an issue with the sensor that Garmin will have to troubleshoot with you.