out on road ride yesterday, noticed that the ascent/descent was only reading around 20m total during the ride, but when I looked back to ride history afterwards it was correct at around 450m.

Just a bug ? anyone else had this ?

Give their helpline a ring, they are very helpful. Mine froze a while back and they talked me through doing a full reset and it’s been good as new ever since…

make sure there’s no crud or anything blocking the 4 small holes on the back of the device. Its where the barometer samples the air pressure from to get the height reading on the fly.

When you upload the file then (depending on your elevation correction settings) garmin connect (and possibly) use a high resolution digital terrain map to derive the elevation based on gps location, rather than obtaining it from the barometer data. It’s a more accurate reading as elevation derived from a barometer will drift as temperature, and atmospheric pressure changes as a result of weather patterns.

Also try and set elevation points at the locations you normally start from. It is a way of effectively zeroing the barometer each ride.

Thanks, will give that a go tomorrow