My friend and I went out last night, both using the aforementioned, Garmin Edge 510. We were no more than a wheel apart for the ride. We did 18 miles. Apart from the parting at the end of the ride, we only live a mile apart. Our stats were so different. According to Garmin, I was 0.5 mph faster than her. Also a few segments were missing. On certain segments, I was finished before her, up to 3 seconds at times. This was not the case as she was in front 100% of the time.


I am waiting on a response form Garmin on this issue.


Anyone else have any or similar issues, if so, did you manage to resolve?


Cheers....

One of you have a speed sensor ?. Maybe the GPS track recording method is different on one unit ?.

When you say you were .5mph faster, does that mean moving average or average? A moving average speed can be different if for instance one of you have autostop on, and the other doesn't, or if one gps drifts around more and the web site ends up considering one of the moving times different than another. If it's average speed for the ride including times you were stopped, then it could come down to when the gps was started and stopped. You could try looking at the reported ride times and moving times.

As for segments... The winner isn't necessarily the person in front at the end. The back person's start on the segment comes after the person in the front. If, for instance, you start 2s later being 2s behind , but then catch up to the leaders wheel by the end, you will have a faster time on that segment because you started 2s later but finished at the same time. Add to that the +/- 1s drift you would probably get from the 1s recording rate of the GPS and you typically wont have identical times even if you think you should have.

My wife very often comes out 1s faster on segments where's she's been drafting behind me the whole way.

If you try to count beans and think that one device should show the same as another you will soon be in the funny house.

There are a slew of differences that might be the cause of the issue. Some already mentioned. One device may have missed the corners of a turn while another didn't. One of you may have been mostly on the outside of a turn the other mostly inside. Either way, one gets less distance.

Are the differences actually as you read them on the device? Or did you upload one or both and get them from a website? Different websites handle the data differently. Differences in how frequent a device logs data will really make a difference from how another device shows up on the same or different website.

The things I'm talking about are really easy to explain graphically, but I don't have any graphics handy.