Virtual Speed and Distance, moving from Strava to Garmin Connect

Like so many people who are pissed off at Strava right now, I’m planning on canceling my premium subscription and moving to Garmin Connect as my main tracking platform. One question I have is around virtual speed and distance that Trainerroad pushes to Strava. I compared the data in Garmin Connect to Strava and realized the virtual speed and distance is about 17% lower on Garmin rather than Strava. I like to compare yoy mileage and 17% variable seems like a big difference. Does this discrepancy sound normal, do other people see a similar difference?

GC just calculates virtual speed/distance on the speed of your freewheel whereas the TR estimate is based on you’re power to weight. I can’t remember the stats but my GC ride recorded something like 12mph the other night (I do all my work in the small ring) , whereas the estimate pushed to Strava was something like 19.9mph.

Sounds like:

  • Garmin is recording speed as reported by your trainer setup
  • Strava receives speed/distance from TrainerRoad

The accuracy of either is up for your review. With my Kickr 2017, the ‘speed’ recorded was based on flywheel speed. Put it in the big ring and 11 ring cassette, and I’d get 25mph while doing endurance which is completely ridiculous. But put it in big ring and something like 18 or 20 on the rear, and I got reasonable speed estimates.

Another example - 2 hours on Zwift a couple days ago and it gave me 20.1mph on a flat course. In the real world that would by closer to 18+mph.

Tracking year-over-year hours is better than tracking miles IMHO. The basics of getting faster start with increasing the amount of time you ride, not how far you ride.


In the past when doing TR workouts on my Kickr Snap the mileage and speed data that eventually were reported in Training Peaks and Strava (pushed out by TR) were identical. As of the past 2 weeks the mileage data have been significantly higher and unreasonable in Strava (i.e., 37.3 Strava vs 33.0 miles Training Peaks) compared to Training Peaks. Been playing around and trying to figure it out, but haven’t figured it out yet.

1 Like

Could it be something to do with your body weight in each platform?

I’ve added 60lbs on to my weight in TR to bring my Strava speed/mileage down.

The idea of tracking hours rather than distance makes a lot of sense, thanks for the suggestion. I do feel like the virtual distances in Strava are a bit generous. Although I guess virtual miles are all made up anyways.