Bryton Accuracy

[Dogfish]

A question for fellow Bryton Users.

when I look at the total elevation gain on historic rides on my device the Total elevation gain differs from the number once uploaded, and the difference can be as much as 8-10%.

 

I have also noticed that my total gain readings are always lower than what is stated in race profiles. this weekend on a race where there was a claimed 1050m my device showed 885m and once uploaded only 794m. This is a big difference!

 

the device is a rider 35.

 

Anyone else noticed this on their devices?

[JGR]

Ive had the same problem with my cardio 35 - also shows about 15-20% less than the route and other devies.

[Daxiet]

Can't comment on the deviation between on device and uploaded value. The difference between your device and the race organisers can possibly be explained by a difference in barometric pressure. Even pilots have to calibrate their altimeters to the airfield they are approaching (QFE for the airfield). Barometric pressure varies based on air temp, weather and possibly a couple more factors, can change rapidly.

 

I found with my ex Garmin Edge 705, that I would leave for a ride from my house at a particular altitude and return to my house which had suddenly dropped 50m's, sometimes even more than 50m (in as little as 1h30mins). All depends on the temp and weather changes during the ride. I also rarely matched up with race specs.

 

So I would say depending on the weather and air temp changes during the race plotting and the weather and temp changes during you completing the race, such a variance is feasible added to that these are 2 different devices used by the race organiser and yourself.

[Bobbo_SA]

I read up on the Garmin site that they do a compensation based on the map details (Topography) etc when the data is uploaded in order to try increase the accuracy of the elevation data, by default a GPS is only accurate to between 8-15m vertically (without a barometric pressure sensor - these can be accurate to about 8-10cm) - thus I can only assume the Bryton site does something similar.

 

Update: It appears that the 35 does have a barometric pressure sensor, thus it could be as Daxiet mentions above, Temperature and humidity related plus some additional calculations that the site does

Edited July 15, 2013 by Bobbo_SA

[Dogfish]

makes sense, but I didn't think that it would affect it by as much as 10%. I will compare exact same routes that I have done in different conditions and see what the deviation is if any.

[JGR]

makes sense, but I didn't think that it would affect it by as much as 10%. I will compare exact same routes that I have done in different conditions and see what the deviation is if any.

I agree - barometric surely cant effect it 10-20% and if so we should be told upfront. im not s astickler for the numbers but more than 5% in not really helpful

[flatwheel]

Can't comment on the deviation between on device and uploaded value. The difference between your device and the race organisers can possibly be explained by a difference in barometric pressure. Even pilots have to calibrate their altimeters to the airfield they are approaching (QFE for the airfield). Barometric pressure varies based on air temp, weather and possibly a couple more factors, can change rapidly.

 

I found with my ex Garmin Edge 705, that I would leave for a ride from my house at a particular altitude and return to my house which had suddenly dropped 50m's, sometimes even more than 50m (in as little as 1h30mins). All depends on the temp and weather changes during the ride. I also rarely matched up with race specs.

 

So I would say depending on the weather and air temp changes during the race plotting and the weather and temp changes during you completing the race, such a variance is feasible added to that these are 2 different devices used by the race organiser and yourself.

I have found the same thing on my Garmin Edge 705. Starting and finishing point at exactly the same place, yet a difference in altitude - suppose they are simply not 100% accurate. However sometimes can be a bit of a pain as you think that you can expect a flat ending to a race and then you continue to climb past your starting altitude :-(

[akneethling]

he difference in altitude stats comes with the upload. Your bryton device measures actual altitude changes, however, when you upload the data, it gets analyzed by an analysis application. So heres how it changes. When an analysis application (brytonsport, sports-tracker, SportTracks) they all have different thresholds at which a flat becomes a climb. Simply put, the application only marks a track an uphill when the gradient is greater than a certain number. With brytonsport, that magic number is 2.5% gradient, with other applications the number is lower, and some are higher. Theat is why you have different numbers after upload. Bryton are telling you that if you ridin a track less than 2.5%, YOU ARE NOT GOING UPHILL.

 

EDIT: Typo

Edited July 15, 2013 by akneethling

[Dogfish]

With brytonsport, that magic number is 2.5% gradient, with other applications the number is lower, and some are higher. Theat is why you have different numbers after upload. Bryton are telling you that if you ridin a track less than 2.5%, YOU ARE NOT GOING UPHILL.

 

 

interesting, that is good to know.

[JGR]

he difference in altitude stats comes with the upload. Your bryton device measures actual altitude changes, however, when you upload the data, it gets analyzed by an analysis application. So heres how it changes. When an analysis application (brytonsport, sports-tracker, SportTracks) they all have different thresholds at which a flat becomes a climb. Simply put, the application only marks a track an uphill when the gradient is greater than a certain number. With brytonsport, that magic number is 2.5% gradient, with other applications the number is lower, and some are higher. Theat is why you have different numbers after upload. Bryton are telling you that if you ridin a track less than 2.5%, YOU ARE NOT GOING UPHILL.

 

EDIT: Typo

I must have missed this on all their marketing material telling me how great their products are ....

[springmielie]

I can't say that I've noticed a significant difference between the device (use a Bryton 35) and the uploaded stats on my rides in the past. I know I did a 1100m climb route yesterday according to my device so I'll pay more attention to the data after I upload it later today.

 

The only significant gripe that I've had in the past is a large variance with the starting point of a route. For example, some days my starting point at home reads -20m and other days up to +30m. I guess that could be explained by the barometric influence as previously explained.

 

Aside from that, I've noticed that the distance readings are quite accurate for races. My readings on my Bryton are usually within less than 100m from the indicated race distance. I'll have to double check on the altitude loss and gain though.

[Vetseun]

Half hi jack...... My bloody Brytons heart rate monitor has just stopped working. Replaced the battery but it just doesnt want to pick up the chest belt sensor. Could it be becuase I havn't done an update in ages? Half hi jack off

Edited July 15, 2013 by T Man

[divernick]

On the altitude differences:

 

Calibrate the device often at a known altitude. I use my driveway, as that's where I start riding a lot. I find this value on Strava.

 

Bear in mind that the Bryton uses barometric data. Once uploaded, let's say to strava, the app itself checks the altitude data and corrects it according to known altitude values. I never trust what the device says, only what it says once downloaded to the app, be it Strava, Endomondo or Brytonsport....

 

On the heart rate strap malfunction: I have heard of this happening. Contact bryton.co.za, they have had a batch of faulties and may replace it under warranty. Don't quote me on that, but they did it for one of my mates who had the same issue.

[Dogfish]

Calibrate the device often at a known altitude. I use my driveway, as that's where I start riding a lot. I find this value on Strava.

 

 

how do I calibrate it?

Edited July 15, 2013 by Dogfish

[Vetseun]

On the altitude differences:

 

Calibrate the device often at a known altitude. I use my driveway, as that's where I start riding a lot. I find this value on Strava.

 

Bear in mind that the Bryton uses barometric data. Once uploaded, let's say to strava, the app itself checks the altitude data and corrects it according to known altitude values. I never trust what the device says, only what it says once downloaded to the app, be it Strava, Endomondo or Brytonsport....

 

On the heart rate strap malfunction: I have heard of this happening. Contact bryton.co.za, they have had a batch of faulties and may replace it under warranty. Don't quote me on that, but they did it for one of my mates who had the same issue.

Thanks! Ill contact them

[akneethling]

Half hi jack...... My bloody Brytons heart rate monitor has just stopped working. Replaced the battery but it just doesnt want to pick up the chest belt sensor. Could it be becuase I havn't done an update in ages? Half hi jack off

Try to reset the hr sensor. Put the battery in backwards. Also try to rescan the sensor. ........ but definitely DO THE UPDATES