I've been running my 520 on two separate bikes. My road bike has speed and cadence sensors. My MTB has no sensors, so I'm assuming the 520 is using GPS and GLONASS for speed and distance. The problem I'm having is that the 520 and the iPhone, running Strava, are way off in regards to distance. If I ride my road bike on my normal route, i'll get 20.7 miles on the 520 and 21 miles. I'm thinking .4 miles isn't a big deal. The problem is that on my MTB ride, the 520 will read 16.5 and iPhone will read 19.8. I'm not sure which unit is more accurate. I also believe I have everything set-up properly regarding settings
All programs that you have on your smartphone filter data this way or other. And actually Garmin has to do that as well (onboard I assume).
Just try and install 3 different programs on your phone (for example sportstracker, strava and endomondo) – and you’ll get 3 different distances due to different level of filtering.
That is just natural thing – since GPS never reports exact location, but “jumps” here and there every moment.
In brief it means that there is no “correct” distance (and I think garmin+wheel sensor is closer to that ideal distance then any gps-only device).
In addition to that – strava looks to post-process garmin tracks as well – at least when test-riding my new 520, garmin showed 14.0Km while strava reported the same ride (uploaded over BT) as 13.9Km (not a huge difference, but still a difference).
So choose either data and believe (strongly) it is correct. I use my old legacy wired bike computer for that (simply because it was installed way earlier then garmin purchase). It is pretty close to garmin, but strava app (used on old Defy) consistently reports shorter distances (it reported around 30Km less distance for the new bike for this season (I did around 1400 Km since I purchased it).
The weird thing is that I normally see Strava reporting _less_ distance (opposed to yours showing _more_ ).
Anyway I would recommend to check autopause options on both garmin and Strava.
If you have autopause off – different algorithms will report different distance when you are standing with no movement (just turn strava on with no autopause and leave for an hour - and enjoy your track afterwards).
And other way around – you have it on and one device may autopause while another will not do it.
So at least set it to the same speed to autopause.
I also recommend setting Garmin to 1Sec mode instead of Smart, that may result in less correct mileage especially if you have twisty trails when you change you direction 180 degrees often.
, so I'm assuming the 520 is using GPS and GLONASS for speed and distance.
If there is a wheel sensor it is used for distance and speed. The default mode is for auto calibration of wheel size using GPS data and that seems to be working correctly. If I understand correctly the MTB distance on the 510 of 16.5 seems to way off. Can you post the FIT files for a ride from the MTB and the road bike.
If there is a wheel sensor it is used for distance and speed. The default mode is for auto calibration of wheel size using GPS data and that seems to be working correctly. If I understand correctly the MTB distance on the 510 of 16.5 seems to way off. Can you post the FIT files for a ride from the MTB and the road bike.
I run the magnetless wheel sensor on my front wheel with an Edge 810. Do not use auto calibration!! It is never accurate. Pump your front tire up to what you would normally run it at have someone mark the floor and roll out one wheel revolution while on the bike. I have found this to be very accurate even when offroading.
It's like power meters, it doesn't really matter which one is exactly right.
The trick is just consistency, so use the same setup and you'll have comparable data if you're looking to analyze it for training purposes.
The 520 will record a location every second. The iPhone typically will not so won't be able to follow a course as accurately. What happens if you overlay the two tracks?
