In the end I was out for about 10 hours and 145km of trail, hill and the occasional road. I did some pretty long detours…some of which were my fault.
I suspected the battery wouldn’t last so I also had some reserves with my 920XT (course loaded just in case) and a MIO 505HC (course loaded) which I’m not really always happy with. The BePros were switched to my MTB within the usual 5 minutes, the sturdy aluminium frame was dwarfed in weight by gels and liquids, the HRM-RUN strap was on. What could possibly go wrong?
Bearing in mind that all that I wanted to do was complete this particular route in one day AND get a complete power track. That was my exercise and my data goal. Simple huh?
When it’s sweet, it’s really sweet. The Edge 820 had me navigating perfectly for over 5 hours. Although I have some vague familiarity with the route I really don’t know all the turns, so the edge got me started at a cracking pace. I was 36 minutes faster than previously on the first half – helped by good navigation AND, of course, by previous familiarisation.
The Edge 820 was used with turn-by-turn (TBT) navigation – GPS+GLONASS, HRV/per-second recording, HRM and PM. It lasted between 7.5 or 8.5 hours, I’m not exactly sure – you’d have thought I could tell from the FIT file but the reality was too complex for me to decipher, so I won’t. Let’s say 8 hours 15 minutes for those of you who want a number.


The Edge 820 seemed to turn TBT off in certain circumstances. And then a reload was required. At the Olympic Park I thought the Edge was broke as everything went super, super slow. When I tried it again later in nav-gadget desperation it was Ok if I left it alone. Various navigation settings seemed to have turned themselves on or off.; maybe it was me. Not sure what went on nor quite sure how to change them back.
The Edge’s screen size is fairly small. However the clear screen/good resolution made it pretty good for navigation in my opinion. It seems to have lots of navigational options – more than I’d ever use.
The one thing that was unusual was that it insisted on drawing a straight pink line from where I was to the next point, as well as the actual route. That was useful in giving me an indication of generally what direction to go in but otherwise a little annoying. No doubt it could be turned off if I knew what is was called. I’m sure it wasn’t on at the start (whatever it was). Oh well.
Even with GLONASS on the 820 seemed about 4 or 5 metres out in the sense of there sometimes being that equivalent amount of delay in telling me I’d missed a turn. Also sometimes when I was SURE I was following the route under tree cover it told me I was 4 or 5 metres out. On the other hand I was sure I was going the right way when I blasted off 2km down a towpath the wrong way…that shows something about my sense of direction and general intuitive navigational abilities.
The 920XT lasted about 9 hours. 8 hours with GPS+GLONASS, HRV/per-second recording, HRM and PM. Then, when I realised the battery was running out I switched on ULTRATRAC and turned GLONASS off to eek out the extra hour or so. So much for the full backup track. Of course there are other power saving features I could have used. I never used the 920 for navigation, although I had the map on it just in case.
Providing you stay ‘vaguely on course’ the MIO navigates quite well. Once you go too far off piste it goes a bit pear shaped and gets confused. Occasionally it comes up with a Windows error for no apparent reason.
The BePro PMs just worked. Lots of battery left.
Life Saver: Combined the resulting data files using the awesome fit file repair tool. It combines, merges, fixes AND makes a mean Latte. so it combined two fit files and added on the TCX file from STRAVA that came via MIO Share (MIO seemed to have turned off FIT export…Grrrrr).
Analysis: Not much to analyse really. Golden Cheetah told me I’d done a Zone 1 ride for a long time. I kinda knew that. Although surprising how many times the zone 4 alert popped up on the Edge for the hills and harder bits in general. I failed even to extend my Zone 2 power duration PB. Oh well.
Other issues:
- Cornering on near-flat front tyre. Ouch. I always wanted a good excuse to buy a new brake lever.
- Danger/Stupidity. My rear has had a slow puncture for months. I liked living on the edge to see if it got me around.
- Not carrying a pump or repair patch and instead relying on an ancient patched inner tube as a backup (that strategy sort of worked).
- The trusting generosity of a random cycling bloke who gave me his pump and sped off and just said ‘post it in that letterbox over there when you are done’ … awesome free pump!! (Joking, I did post it obviously).
- Sugar. You can only drink so much Lucozade Sport. There should be a dental-law against drinking more than 4 in a day. (Actually there is, in Lithuania. I was in London.)
- Dog owners. Actually most of them seemed pretty good and realised that it was their responsibility to keep their animals under control. Wonder never cease.
- Dog mess not cleaned up – Worst in SE London especially anywhere near a train line, best in SW London where there are most dogs and best in N London where dogs appear to be banned.
- Multiple dogs. How many dogs can a single person own? The answer is at least 8. Wow.
- Extending leads. How long can they be. Answer: always just that little bit TOO long for safety.
Great Article. Thanks