Bike Computer To Strava.

Roger Longbottom

Über Member
All, am new to the world of cycle computers, (birthday present).

Used it for first time yesterday, have it on auto upload to Strava and everything matched fine.

Went out today, being egged on by being able to see time and distance so was computing average mph in my head and was pleased on my return. Was pleased with what the bike computer said, fastest I have been for a while.
However when it uploads to Strava it gives my mph .2 slower than the bike computer showing I was out longer than the computer says. What Strava says doesn't even match the elapsed time on the computer.
.2 mph may not sound a lot but I was pulling my tripe out for it!!
 

cyberknight

As long as I breathe, I attack.
thats normal
strava auto corrects your data based on better maps and elevation data.
 

Dogtrousers

Kilometre nibbler
If you calculate something that depends on an estimation algorithm - like moving average speed, total elevation gain, watts or calories then you will get different answers depending on who does the calculating : different websites, GPS devices etc.

That's why you should choose one method and stick with it. Never compare between methods. And don't ask what is the most accurate. Just pick one and stick with it.
 
OP
R

Roger Longbottom

Über Member
I'm still a bit sceptical based on yesterday's upload.

Bike Computer.
Moving Time 1.01.06
Elapsed Time 1.02.24
Strava 1.01.06 Identical to the moving time on the computer.

Today
Bike Computer
Moving Time 54.49
Elapsed Time 55.54
Strava 55.30.

Surely when it uploads, it should upload the moving time.
N.B. Strava was not running concurrently, this is an after ride upload so the satellites would have bearing.
 

Dogtrousers

Kilometre nibbler
Surely when it uploads, it should upload the moving time.
No, it will upload the ride as a series of location points with the time at which the location was recorded. Strava will interpret this string of points as a track, and from the position and time will infer whether the GPS was in motion.

Your GPS will also, independently figure out whether or not it is in motion and will come up with a moving time.

The two will differ.
 

newfhouse

Regressive elitist lefty
Had it confirmed that it had a full GPS fix before you pressed the start button?
 
OP
R

Roger Longbottom

Über Member
No, it will upload the ride as a series of location points with the time at which the location was recorded. Strava will interpret this string of points as a track, and from the position and time will infer whether the GPS was in motion.

Your GPS will also, independently figure out whether or not it is in motion and will come up with a moving time.

The two will differ.
Still seems queer to me that the moving time yesterday was identical on both the computer and Strava yet today Strava has added forty seconds on what was the same route.
 

Dogtrousers

Kilometre nibbler
Still seems queer to me that the moving time yesterday was identical on both the computer and Strava yet today Strava has added forty seconds on what was the same route.
They're different tracks. It's fairly tricky to detect on a GPS track whether the recorder is stopped. Even when stopped the points will dither around. So two different tracks will give different results.

Seriously, choose one method to trust and stick with it. Ignore other methods. Comparing methods will just cause premature ageing and general woe.
 
Still seems queer to me that the moving time yesterday was identical on both the computer and Strava yet today Strava has added forty seconds on what was the same route.
Its quite simple, the bike computer autopauses at say 4mph but strava doesn't autopause to say 2mph (I dont know the exact mph numbers) so if you're travelling at 3mph for a second or two strava hasn't autopaused but the computer has paused the timer. Over the course of a ride these differences will easily add up to 40sec. 0.2mph is very normal nearly all my rides are 0.1-0.2mph slower in strava than on the computer unless its a ride with minimal stops.
 
OP
R

Roger Longbottom

Über Member
Sorry I still can't get my head around it, I wasn't recording on Strava so I don't see how the auto pause comes into it, I uploaded the ride, and it still doesn't explain how yesterday the timings were identical and yesterday's ride like today's involved road junction / traffic light stops hence the elapsed being over a minute longer than the moving.
Guess I'll see what happens tomorrow.
 

figbat

Slippery scientist
When the data goes to Strava, it goes as raw waypoints, it doesn't go as the 'processed' speed and distance data. Strava then treats that data as if it had recorded it itself, interpreting the waypoints and processing it in its own way to give speed and distance results. Your first ride coincidentally gave the same time result but this is likely to be the exception rather than norm.
 
Top Bottom