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Edge 820 not showing Grade above 16%

Former Member
Former Member over 6 years ago
I have an Edge 820 with Firmware 11.0 and a speed sensor which I use when Mountainbiking.

The "Grade" is unreliable around 15% and generally does not show values above 16% - it just shows 0%, or sometimes a few %. The "Totl. Ascent" will increase, but only seems to do that every now and then ... lets say each 15 seconds ... and normally in larger increments (like 5-10 meters). So, overall its accurate.

To me it seems like there are some smoothing algorithms in place, and perhaps I don't ride fast enough on the very steep climbs (8 kph on a 20% climb) for those algorithms to correctly evaluate the Grade.

My previous Edge 510 worked just fine up to and beyond 30%. At that point it might not have been that accurate ... but it was closer to the truth than 0% is!


Any ideas?
  • 0 over 6 years ago
    I have exactly the same expercience as described above. I also have external speed sensor deployed and communication set to GPS+Galileo. Almost (rougly over 90%) all steep climbs are recognized as "zero" by the unit.
  • 0 over 6 years ago
    Did a little comparison today: mountain biking with both the Edge 820 and the older Edge 810 on the same bike (+ speed sensor on the hub paired with the 820). On some forest trails, the 810 produces the same symptoms (i.e. 0 instead of double-digit percentage gradient on steep climbs), but less often than the 820. I installed 3 different Connect IQ gradient apps and had them on the 820 screen displayed simultaneously: RGrade, Sensible Grade, and Altimetric Gradient (they all claim to rely on pressure, bypassing the GPS). Sensible Grade is somewhat more similar to the default Garmin (takes a bit longer to adjust), but is still reliable and shows, for instance, 10% or 13% where the default Garmin field would still show 0. Rgrade and Sensible Grade are pretty comparable and they seemed to converge the most with the old Edge 810 values. As I said before, on longer climbs without trees, the Garmin default gradient field settles on the correct value after a while, but its behavior during mountain biking is really sub par. For some reason, riding downhill the 820 shows correct gradient values more in line with the Connect IQ apps (and the 810) even in areas with tree coverage (so I guess this problem also has sth. to do with speed)
  • 0 over 6 years ago
    I pretty much always experience this issue. I have a speed sensor and use GPS. 800 used to do this also, I had hoped the 820 would be better but no. TBH I don't generally need to know how much above 16% a climb is as my lungs are telling me it's steep enough..
  • 0 over 6 years ago
    I'm a road rider and my routes have lots of shortish (a few hundred yards to 1 mile), steep hills @ 10-17%. I bought a Garmin Edge 705 in 2010 and never had any issues with % grade going to 0%. The % grade varied some from day to day (due to the atmospheric conditions/barometric readings I assume) but it was consistent within a few degrees and never went to 0%.

    So the 705 finally gave out and I just bought a 520 Plus. Now I'm having the same issues described above i.e. 0 grade reading on steep hills etc, etc. Did some searching and it seems this issue runs across many/all recent Edge models? I'm thinking I'll return it but not sure what model to replace it with. Maybe another brand? Anyone know of a newish model bike computer that actually works on steep grades?
  • 0 over 6 years ago
    I'm a road rider and my routes have lots of shortish (a few hundred yards to 1 mile), steep hills @ 10-17%. I bought a Garmin Edge 705 in 2010 and never had any issues with % grade going to 0%. The % grade varied some from day to day (due to the atmospheric conditions/barometric readings I assume) but it was consistent within a few degrees and never went to 0%.

    So the 705 finally gave out and I just bought a 520 Plus. Now I'm having the same issues described above i.e. 0 grade reading on steep hills etc, etc. Did some searching and it seems this issue runs across many/all recent Edge models? I'm thinking I'll return it but not sure what model to replace it with. Maybe another brand? Anyone know of a newish model bike computer that actually works on steep grades?


    Just install a grade app from Connect IQ. That's what I've done
  • Former Member
    0 Former Member over 6 years ago
    I gave a few Connect IQ apps a test today ... here is a summary of my observations:

    Garmin Grade - actually works quite well for moderate grades; reacts fastest to large changes from +ve to -ve grades; but has the most lag for more moderate changes in grade. Without a good GPS Signal (i.e. Mountainbiking) it will loose the grade on 15%+ climbs.

    Sensible Grade - accurately shows grades above 15%, has about a 5 second lag to grade changes, and slow to react to negative grade changes, or large changes (perhaps both or the same).

    Altitude-Grade - pointless (on an 820 at least). Had no idea what was going on.

    Grade - Tended to be fairly different to any other grade field, not as bad as Altitude Grade, but generally always off the others.

    Rgrade - More reactive than Sensible Grade, perhaps too reactive as the values were sometimes too high. Otherwise, similar to Sensible Grade.


    If I would do it myself, I would take the algorithm from Sensible Grade and combine with with Garmin Grade, selecting the value from one or the other based on the quality of the data. Garmin handled the end of a steep climb better than Sensible Grade, mostly because Sensible Grade had that consistent lag to grade changes. Or both values actually - there is room.