There’s no denying that the Garmin Edge 800 is an attractive and intelligent piece of kit. However it has a design flaw.
During last month’s climbing challenge I noticed that when it rained, the Garmin’s altitude readings went haywire. Typically, it stopped registering any change in elevation which was quite frustrating.
Initially I thought the device was faulty, but some Googling around revealed that the Garmin has a small hole in the back which allows an internal sensor detect atmospheric pressure and temperature. However, a small droplet of water can clog the hole and block the sensor.
After hunting around on the interwebs, I discovered that Garmin manufacture a silicone case for the E800 which covers the offending hole, but with a groove to still allow air movement.

The groove allows air movement but runs down the body of the Garmin so there should be no way water can find its way up

Product spec – this can be ordered from Amazon but be warned, they posted it in a parcel the size of a shoe box. The case could probably be rolled to fit in a matchbox
My verdict on this accessory is that it is essential if you own a Garmin E800 and cycle in the rain. But what irks is that you shouldn’t have to hand over more cash to Garmin to resolve their own design flaw.
If you really don’t want to pay extra to protect the device, there is always the sammidge bag solution. However I was consuming two sammidge bags a month which would have equated to the cost of one Garmin silicone case in less than a year. The price you pay for living in the rainiest part of the UK…
It annoys me too that there’s a design fault like that. I am finding that the SD / USB slots keep coming open on my Garmin Edge 800. I use mine on my motorbike as well as on my bicycle and I hold it when I run / hike. Sometimes I worry that it will suffer water damage from the SD / USB slots not staying closed …
Apparently the SD & USB slots are waterproof but you can have an issue if you’re using a micro-SD card as it won’t be waterproof. I use a micro-SD card for maps so I guess the answer is to take it out from time to time and give it a wipe. Not something I’ve ever done, but maybe something I should do right now ……. thanks for the prompt 😉
When they designed the rubber case, why didn’t they close the part of the cable and the SD too? Just take it out of the case when you charge it, not a big deal. I have doubts with the way the Edge is fixed to the bike. The very first day I used it on my mountain bike I found it was half way turned, close to falling of from the bike fixing. If it fell I wouldn’t even realise. I guess a brunch or a hard jump or whatever made it turn and nearly come out. I don’t care what did it, it simply shouldn’t happen!!
I bought the rubber case with the intention to make a small hole on it and fix that to the bike with a string or something… just for safety…
I haven’t ridden with my Garmin for over 2 weeks now. It’s a nice bit of kit but is overpriced and I wouldn’t buy it if I had a second chance. Oh well… Thanks for commenting
I have the rubber case and the hole still gets blocked in heavy rain!