Garmin or Strava?
enzo berzot
Posts: 96
On recent rides with my friend my Strava stats are way off his Garmin stats which he uploads to Strava.
Distances are identical, as are calories used but height climbed and average speed are very different despite us cycling together.
Should I bin my free Strava on my phone and upgrade to Garmin kit?
Distances are identical, as are calories used but height climbed and average speed are very different despite us cycling together.
Should I bin my free Strava on my phone and upgrade to Garmin kit?
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So what if it's different?
when computing average speed, i'd assume one is only including time when moving, that can cause a large variation if the other is simply doing speed = distance / (end time - start time)
altitude is always iffy - consumer gps altitude accuracy is poor, barometric sensors are slow to respond, strava has no special magic giving it accurate altitude data for each point on the road
and as m'learned colleague says above, so what? it really doesn't matter, switching to a garmin simply gives you a different set of data, which'll probably still be wrong
As a disillusioned Strava user I wondered if Garmin was more consistent and accurate?
The only discrepancies you mention were height gain and average speed. Those are hardly 'critical' in terms of training metrics.
The question is, does changing from one wrong model to another give you any additional utility? Probably not in this case.
Personally I like the barometric altitude from my garmin since it's more granular than the map-based calc from Strava, but it still has major flaws (such as if the ambient pressure is changing the altitude gain/lost can be ludicrous).
2) Average speed - moving or elapsed? - If you're trying to get faster over distance then a shorter elapsed time is the ultimate goal - however, most of us use moving speed as that's the one we have most control over.
3) Elevation gain - this differs on the same ride between units of the same make/model - Strava offers an elevation correction that resets it back to it's own calculation based on stored elevation data rather than barometric or consumer GPS derived data - both methods have their limitations - perhaps we should stop looking at absolute height gained (do you count the 6" over each speed bump - do a dozen of those and it's another 6' height gain!) and fuzzy the metric - flat, moderate, hilly or mountainous ... that'll do ..
If the elevation is recorded by a device with a barometer and Strava and Garmin are set to use the recorded data the elevation climbed will be identical. If elevation correction is turned on then the recorded elevation is ditched and the elevation is computed from various map data etc. This will produce differences.
Strava elevations generally over-read compared to a barometric altimeter.
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Thanks all for your input.
I'm merely looking for an acurate training mode and appreciate it is unhealthy to be too hung up on stats but it is confusing to see wildly conflicting results.
Here are the stats which are odd - both from 2 riders covering the same route pretty much behind each other with 1 cake stop:
My Strava = 35.7 miles / 1596 feet altitude / 15.8 Ave / moving time 2hrs 15
Pal's Garmin uploaded to Strava = 35.5 miles / 1863 feet altitude / 16.2 Ave / moving time 2hrs 12
Oddly different altitude and average.
I know it is freakishly pedantic but what's the point of basing your training stats on something completely unreliable!
I wonder if your stats had been better than his garmin ones then you would be looking to swap ?
Regarding the different moving time figures, you need to be aware of how Strava calculates what constitutes stoped time... and I quote Strava...
Strava considers a point "not moving" if your speed is less than 0.3 meters/sec (0.67 mph), but we don't start accumulating resting time unless you're "not moving" for at least 15 seconds.
Wilier Cento Uno SR/Wilier Mortirolo/Specialized Roubaix Comp/Kona Hei Hei/Calibre Bossnut
The averages are not bad. For altitude, it is complicated as others have said.
GPS calculated altitudes are inaccurate. Even more so they are inaccurate between each reading. If you are climbing a hill you would expect your altitudes to increase like this:
1,1.5,1.9,2.4,2.7,3,3.5...
but with a GPS you may get
1,1.5,1.3,2.0,2.5,2,4,3,3.5
Altitudes from GPS reported by Strava
where the altitude bounces around a lot, these cause cumulative errors.
Altitudes from Garmin 1000 with barometer - much smoother
If you take the strava altitude data you are relying on the strava data actually being accurate for a given point and your gps accurately reporting where you are. Lots of factors will affect this - terrain, trees, buildings etc. If you are climbing a road that traverses up a hill then a location a few meters to the left or right will make a big difference in altitude and again, all errors are cumulative.
A barometric altimeter is better but are affected by changes in barometric pressure (changing weather) and temperature and tend to under read over long climbs. As reported above some Garmin's are sensitive to wind. (see: https://forums.garmin.com/archive/index ... 33043.html)
Some altimeters will mix GPS and barometric data and you can even enter known waypoints to correct if you pass throught them (useful for summits and cols).
Just a note on the Strava data, they've built up their own database based on barometric data submitted by riders, which is a clever thing to have done but still relies on positions being accurate or dropping obviously erroneous locations from input data.
see also: https://support.strava.com/hc/en-us/com ... elev-gain-
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True!
Voltaire
It seems there is no definitive answer to my question but really interesting to hear of the pros and cons of both methods.
Looks as though I'll stick with Strava on the phone for now...
Yes - my average speed on familiar routes tells me (generally) if my overall fitness is improving over time. Elevation is more out of interest to be honest.
Plus, I like stats..
Only if you've not set it correctly. A Garmin or any other dedicated device, when set correctly, will show both average moving speed and average speed. It's easy enough to differentiate between the two.
How do you know that his Garmin isn't incorrect and your phone strava app correct???
Also on the Garmin you can set your home altitude and this may have an effect on altitude gained especially if you are starting from somewhere other than the home location.
My Garmin GPSMap handheld GPS device does have an average moving speed data field as well as an average speed data field.
Both are reporting very similar distances and average speeds, typically within 3-5%. The most obvious difference is the altitude gained reading. Garmin almost always reads less than Strava, as much as 30% less on one ride. The closest they have been is 4%.
One thing is for sure, the Garmin has a much more accurate GPS. Strava on my phone often ends up looking a bit zig-zagged. Strava must have some pretty clever ways of cleaning up that data.
From what I understand, these miniature barometric sensors are more accurate than GPS but not by a huge margin.... They still have a reasonable amount of error in them and things like temperature and humidity easily affect them.
I love the Garmin on the bike, I'm a bit of a data fiend. The only downside is it's crappy touch screen. It's SERIOUSLY censored .
Tip for the touch screen to try. Touch slightly longer than a 'normal' touch screen, about half a second works for me.
Voltaire