Garmin speed dropout problems.

anyone seen anything like this before? regular and repeated drops in speed? this was on the road bike which has the new style wheel speed sensor but I’ve seen it less frequently on the MTB which only uses GPS for speed.

its a garmin 520 running the latest firmware (3.10)

I thought it only used the speed sensor if the GPS signal disappeared?

I think it uses it to detect movement and it possibly overrides the GPS speed as well.
Best way to debug this would be to first do the same route with the sensor disabled and see if it does the same, then try giving the sensor to someone else.

a lot clearer on garmin connect.

only seems to do it when climbing at less than 10mph.

You haven’t got auto pause set at a relatively high speed have you?

nope. auto-pause turned off.

There’s a Quinetic research establishment near me, and a Navy radar test station type place (on Portsdown Hill) and whenever I ride within a mile or so of there I get terrible glitches in my speed data from the Garmin. My wife’s does the same.

Check the magnet? Had this with the sensor. Since then I’ve not bothered with sensor. Just use GPS. Otherwise not seen this on my Garmin 800 or 1000 both with GPS only

It’s not a magnet speed sensor, it’s the newer interial unit