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  1. #1
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    I Can no Longer Recommend Strava.(Strava fixed the issue)

    It use to be pretty awesome, but now they have switched over to just using GPS points to calculate ride data. When my rides start coming in 9 miles under what I actually rode and they take my speed/cadence sensor out of the calculations; I can no longer recommend it as a training tool.

    This was all done to account for the uptick of mobile phone users. So beware of using Strava for now.


    "Strava switched from processing the distance/speed data recorded by the Garmin, to creating our own data set. Basically, right now, we are taking the GPS data in the file, and processing the distance based on the GPS coordinates. So we are calculating the distance between each recorded GPS point and adding them up. This will override any data you may have from a speed sensor, and may even be different that the Garmin's GPS-based "real-time" distance calculation.

    We feel this is the most consistent way to get distance data across all devices, including mobile devices. We understand that the data may be different than what Garmin reports.

    Sorry for the confusion!

    Best,
    Elle
    Strava Support Team"
    Last edited by PainkillerSPE; 04-12-2012 at 05:26 AM.

  2. #2
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    Do you know when that changed?

    Comparing the data between Garmin Connect & Strava from my ride on 4/7/2012 using a Garmin Forerunner 410:

    Distance AvgSpeed MovingTime
    Strava 8.1 8.2mph 59:30
    Garmin 8.05 8.2mph 58:54

    This ride was pretty jacked, though. Tons of stops. Riding with a bunch of people with various fitness/skill so we stopped a good bit, then one of the guys dropped a kidney stone and was in bad shape so we hobbled him out. I wonder if the stops and such made any impact on how the data compares, so I'll keep an eye on how they line up going forward.

    Looking at a buddy's data for a road ride he did yesterday using a Garmin Edge 705, 4/8/2012:

    Distance AvgSpeed MovingTime
    Strava 43.4 15.6mph 2:46:32
    Garmin 43.48 16.0mph 2:43:09

    He said he stopped at a couple places to pick up a few items and have lunch, but that data lines up pretty well.

  3. #3
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    FWIW, I`ve been double-uploading all my Edge 500 rides to Strava and Garmin connect, and I`m not seeing any material difference in distances. Including (what I think are) twisty mountain bike trails.

    I dunno, are my trails just straighter than yours? Is your device set for 1-second logging?
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  4. #4
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    I hear ya.

    I don't see strava as a super accurate training tool. Its a way to compare times with other people, and a motivational tool. You could always upload your data to GTC or sporttracks as well as strava, or only upload the rides to strava that you want to get times on segments. That way you would have the more accurate data, as well as be able to see your times on segments etc. Since the main goal of strava is accurate comparision it makes sense to do that as accuratly as possible. Unfortunatly the GPS in mobile phones is not very accurate, and the GPS in garmin devices is very accurate. this makes comparision between the 2 difficult. So since there is no way to make the iphone more accurate they have sent with making the data from garmins less so. Pertsonally I think they should add a fliter so you could just look at data recorded from gps devices, or just data recoreded from phones, or all data.
    The Iphone 5 is rumored to have an improved GPS antenna so maybe it will help to close the gap.
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  5. #5
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    Quote Originally Posted by Pedalfaraway View Post
    The Iphone 5 is rumored to have an improved GPS antenna so maybe it will help to close the gap.
    A better antenna is only part of the equation. As mentioned in an earlier discussion (not specific to Strava), phone apps HEAVILY process the raw GPS data to get anything useful out of it.

    If phone users want better GPS accuracy, they should just buy a dedicated GPS. But of course that cuts into Strava's business model of selling its app to people. Strava is heavily invested in people using phones.

    You probably also shouldn't be using a low level website as your training logbook, either.

  6. #6
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    I liked the segments and competition on Strava. But with this screw up, I'm going back to Garmin Connect.

    My road rides are pretty accurate but my mountain rides are off by 9 miles on some occasions. I use one second recording and a wheel sensor.

    <iframe width='465' height='548' frameborder='0' src='http://connect.garmin.com:80/activity/embed/165738107'></iframe>

    Mountain Bike Ride Profile | 6 Hours of Warrior Creek near Beaver Creek | Times and Records | Strava

    Strava will not embed on this site, but the same ride in Strava comes out to be 45.3 miles and my average is only 9.0 mph. Way off and unacceptable for me especially if you are paying for the service.
    Last edited by PainkillerSPE; 04-09-2012 at 10:06 AM.

  7. #7
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    That's pretty ridiculous. I only use the free Strava, but I will definitely keep an eye on the data between it and Garmin Connect. Can you delete and then re-upload it? I don't think you can, but not sure.

    I went for a jog with the dogs during lunch today and the data compares fine, but that is only ~23min worth of time. Again using FR410.

  8. #8
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    Quote Originally Posted by NateHawk View Post
    But of course that cuts into Strava's business model of selling its app to people. Strava is heavily invested in people using phones.
    To be clear, the apps are free, they are selling the $6 a month subscription to idiots like me, which is much more lucrative.

    Quote Originally Posted by PainkillerSPE View Post
    Hours of Warrior Creek near Beaver Creek | Times and Records
    Alright, point is indeed taken, I can see that kind of ride causing some major mileage losses if the wheel magnet distance info is discarded.

    But I think the core of strava's popularity is letting people race one another on segments, and I think most or all of the mods they are making right now are towards improving that.

    Garmin connect does indeed have more overall functionality if you drop the segment racing crap out of the equation. But then, the segment racing crap is the reason I joined strava....
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  9. #9
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    Quote Originally Posted by ghettocruiser View Post
    To be clear, the apps are free, they are selling the $6 a month subscription to idiots like me, which is much more lucrative.



    Alright, point is indeed taken, I can see that kind of ride causing some major mileage losses if the wheel magnet distance info is discarded.

    But I think the core of strava's popularity is letting people race one another on segments, and I think most or all of the mods they are making right now are towards improving that.

    Garmin connect does indeed have more overall functionality if you drop the segment racing crap out of the equation. But then, the segment racing crap is the reason I joined strava....
    The segment racing was the reason that I joined as well, but if you are going to dumb down hard earned efforts then it's not worth it. Some rides I really hammer out trying to beat other peoples times, only to find out that it was no way near what my computer said.

  10. #10
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    I agree. If the data is being edited by Strava, then the times will be suspect.

    Next time I go out to ride (hopefully tomorrow after work) I'm gonna record with iPhone 4S and my Garmin at the same time and compare the data. Last time I did that, the data was pretty close. This was over a month ago. Here's how they compared:

    Device Garmin Forerunner 410
    Time 01:16:11
    Distance 21.0mi
    Elapsed Time 01:16:11
    Max Speed 24.4mph
    Avg Speed 16.6mph
    Cadence N/A
    Bike Redline D440 1x8 29er

    Device Strava iPhone App
    Time 01:17:22
    Distance 21.2mi
    Elapsed Time 01:48:49 (i forgot to stop the app after the ride for a bit)
    Max Speed 26.5mph
    Avg Speed 16.4mph
    Cadence N/A
    Bike Redline D440 1x8 29er

  11. #11
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    The problems I've seen with segments are threefold:

    -Failing to recognize a segment in a tracklog of a ride that includes it.
    - False recognition of a segment from a tracklog of someone riding a shorter variant or an adjacent route.
    - Questionable start-stop locations of segments due to a lack of well-placed tracklog points at or near the start and end of the segment.

    I'm not really sure that all of these problems can be solved with more server-power, and they may need to appoint regional moderators to look after some things manually, since they seem to have pretty limited staff available to solve all manner of inane complaints, myself being part of the problem.

    The issue they are having now seems to be that so many people have joined these last few weeks that their servers are overloaded half the time... someone makes a new segment, it takes four or five days just to pull in the archive segment times back to mid-2011.

    I'm not gonna make many friends for saying this, but they should probably cut back some of the functionality for unpaid members (create maximum of five segments maybe) to free up some resources.
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  12. #12
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    Sounds a lot like the issues Motionbased had back when their service really started to take off way back when. And a lot like a lot of the issues Garmin Connect had back when their service took over Motionbased and shut down the old site functionality prematurely.

    Some people just don't learn, which is a bit surprising to me, since AFAIK, Strava has a lot of the old Motionbased staff.

    To be clear, the apps are free, they are selling the $6 a month subscription to idiots like me, which is much more lucrative.
    If this is the case, I don't get why they're trying to put users of inaccurate cell phones in a position where they can potentially set an inaccurate segment record. Use speed/cad sensor data when available. It's not like that stuff is unavailable to cell phone users. The ANT+ protocol is available as OEM features on many phones, and many other phones can take a dongle. All it would take is Strava to make their app compatible with such a sensor for phone users to have the increased accuracy.

    And for all we know, they could be working on this already.

  13. #13
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    Quote Originally Posted by Camel Toad View Post
    I agree. If the data is being edited by Strava, then the times will be suspect.

    Next time I go out to ride (hopefully tomorrow after work) I'm gonna record with iPhone 4S and my Garmin at the same time and compare the data. Last time I did that, the data was pretty close. This was over a month ago. Here's how they compared:

    Device Garmin Forerunner 410
    Time 01:16:11
    Distance 21.0mi
    Elapsed Time 01:16:11
    Max Speed 24.4mph
    Avg Speed 16.6mph
    Cadence N/A
    Bike Redline D440 1x8 29er

    Device Strava iPhone App
    Time 01:17:22
    Distance 21.2mi
    Elapsed Time 01:48:49 (i forgot to stop the app after the ride for a bit)
    Max Speed 26.5mph
    Avg Speed 16.4mph
    Cadence N/A
    Bike Redline D440 1x8 29er
    They would probably be pretty close unless you use a wheel sensor. Even Garmin computers are inaccurate without the speed/cadence sensor. The sensor overrides the signal strength and drift issues that would otherwise cause your numbers to be off.

  14. #14
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    Quote Originally Posted by NateHawk View Post
    If this is the case, I don't get why they're trying to put users of inaccurate cell phones in a position where they can potentially set an inaccurate segment record.
    I guess people would rather risk losing a second or two to a technological glitch (and see themselves ranked in a much larger pool of riders) than be "1st overall out of 2 riders" that had garmins with wheel magnets?

    Maybe this isn't the case in places where everyone and their dog races SRM-equipped road and mountain bikes. I've actually seen complaints on line that strava should require power-meter input to prevent vehicle-assisted segment trolls. Go figure.

    But personally I used a phone for a few months, then bought the 500, and I haven't seen any material difference in ride times, other than the usual speeding-up as the weather gets warmer. Phone-GPS or not, I find the guys who are ahead of me on Strava segments can also drop me in real life.
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  15. #15
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    Quote Originally Posted by ghettocruiser View Post
    I guess people would rather risk losing a second or two to a technological glitch (and see themselves ranked in a much larger pool of riders) than be "1st overall out of 2 riders" that had garmins with wheel magnets?

    Maybe this isn't the case in places where everyone and their dog races SRM-equipped road and mountain bikes. I've actually seen complaints on line that strava should require power-meter input to prevent vehicle-assisted segment trolls. Go figure.

    But personally I used a phone for a few months, then bought the 500, and I haven't seen any material difference in ride times, other than the usual speeding-up as the weather gets warmer. Phone-GPS or not, I find the guys who are ahead of me on Strava segments can also drop me in real life.
    I don't remember which thread it was, but there was a guy saying in here that there was a lively discussion in his riding group about Garmin vs. cell phone specifically related to the Strava segment rankings.

    It may be more of a case that the cell phone users feel that they are disadvantaged compared to Garmin users because their cell phones are often underreporting by a hair compared to the Garmins.

  16. #16
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    Strava has been fixed!!

    Well it looks like enough of a fuss was raised.

    Elle Anderson
    Hello everyone:

    The change to distance calculation was done to improve some the errors we see from GPS devices. We now realize that the change adversely impacted some users and we have reverted our distance calculation to our previous method.

    We're always looking for better ways to tune data calculations to ensure the most accurate possible representations of activities for all of our athletes. Accuracy is a top priority here at Strava and we appreciate you bringing this to our attention.

    Please send Support the URLs to any adversely affected rides in a new support ticket, and we'll be happy to correct the distance for you.

    If you are experiencing issues with your moving time calculations and the correct detection of time spent in "auto-pause", we have not yet found a solution, but we are working on it. If you have any good examples of activities where auto-pause was not detected properly by Strava, send those along in a new support ticket too! It would help us track down the issue and appropriately design a fix.



    Thanks to all for your feedback and patience.


    -Elle

    Strava Support

    Just re-uploaded my ride and everything is spot on now. More segments are showing up as well.
    Last edited by PainkillerSPE; 04-10-2012 at 01:38 PM.

  17. #17
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    I did a little testing two weeks ago with a Droid X and Edge 200 on the same rides. They were usually pretty close, however if there was any time advantage on a segment it was always given to the phone (usually 1-2 secs. In one case my GPS was 1 sec faster). On some segments the advantage was 12-20 seconds. On one segment the phone gave 12 seconds - the difference between 1st and 5th place.

    It is frustrating getting beaten by someone you know was using an iPhone and suspect got a "bonus" - but maybe I shouldn't care so much.......
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  18. #18
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    good to hear they put it right. sounds like they're trying to figure out the auto pause inconsistencies. that's fair, I guess. I always found auto pause to be a PITA, anyway.

  19. #19
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    Not sure I'm buying that the phone can have consistently faster times, since as far as the phone 'knows' the segments are randomly selected from the tracklog, which has to give the same overall time at the end of the ride as the garmin.

    If the phone was using a longer sampling interval than the garmin, and strava was always picking the shorter trackpoint as the end of a segment rather than the longer one, then I can see an advantage of a second or two. But with my phone at least, I saw nothing.
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  20. #20
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    Quote Originally Posted by ghettocruiser View Post
    Not sure I'm buying that the phone can have consistently faster times, since as far as the phone 'knows' the segments are randomly selected from the tracklog, which has to give the same overall time at the end of the ride as the garmin.
    Hmmm, I don't know why it's true - but it is with the testing I did (in all but one instance). And friends have reported the same results. That's not to say I don't think a phone could also "rob" you of some time - but that hasn't been my experience.

    As an example, here is a comparison of the same trail as recorded by a Garmin Edge 200 and Android phone....



    As you can see the phone thinks you are wayyyyyyyyyy off the trail. So it probably thinks you crossed the finish line much earlier than you did.....
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  21. #21
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    Possibly, but when my phone did that it, it didn't recognize the segment at all,

    Which is a harsh result when you've busted yer ass to record a PR and get a mess of a tracklog that has nothing. But at least there's no inadvertent cheating.

    Could be a question of topography. I mean, it's pretty flat around here, no mountains to block skyview, and the few segments we have that do involve bridge underpasses and buildings are more error-prone.
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  22. #22
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    I have seen some activities that have to be messed up...like logged as a run, but the person was probably riding. He has a logged 8.5mile run, where somewhere in the middle he rocked a 3:24 mile...which would be a world record haha

  23. #23
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    Strava and Garmin are very close and I run a wheel sensor.

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    Quote Originally Posted by canuck_tacoma View Post
    Strava and Garmin are very close and I run a wheel sensor.
    They reverted back to the old method and everything is spot on now.

  25. #25
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    More information

    Hi Everyone - we, at Strava, wanted to send along a bit more information here to any one who is interested. I see some of our responses to this discussion have already been shared on this forum. Please see below for some a more in-depth response.

    When a Garmin file is uploaded, Strava takes the distance data recorded in the file and parses it into a data stream to calculate total distance, average speed and max speed. Depending on which method for recording distance is used, that data will be reflected in the distance stream, and thus on Strava. Differences should be minimal when comparing distance or speed metrics on Strava versus the Garmin device, but any small inconsistencies are likely due to number crunching on both ends - Strava proceses and analyzes the data in the file independently, whereas the Garmin tabulates these values on the device itself.

    When mobile data is synced with our servers from the iPhone or Android App, Strava runs a GPS-based distance calculation on the GPS coordinates, as there is not currently a way to gather data from a speed/cadence sensor from the Strava App.

    For a period of about three weeks at the end of March/beginning of April, Strava initiated a system-wide switch to post-upload GPS-calculated distance. This switch recalculated the distance streams coming from all Garmin uploads, regardless of whether the file contained data from a speed/cadence sensor, a Power Tap hub, or Garmin's GPS-calculated distance. This change was initiated in an attempt to improve some of the errors we see from GPS devices, like stuck points and inflated distance from badly calibrated speed/cadence sensors (always good to check if you entered your wheel size correctly for best distance measurements).

    This change was not motivated by mobile data, either to make Garmin data more comparable to mobile data, or to make all forms of data across Strava more consistent. Also, distance data does not affect Strava segment times.

    We realized that the change adversely impacted some users and we have reverted our distance calculation to our previous method, as stated above. We will continue the project and continue with our goal of improving the data and calculations on Strava. The reasons why we initiated the system-wide distance calculation change are well-intended and well thought through. Innovation and accuracy are top priorities at Strava. Going forward, we will continue to address the issues around stuck points, distance inaccuracies, and consistency with speed sensors.

    Thanks to all for your feedback on this.
    -Strava

  26. #26
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    Thanks for the clarification and thank you for continuing to innovate. That kind of creative thinking pushes everyone in the industry to do better

  27. #27
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    Quote Originally Posted by NateHawk View Post
    Strava's business model of selling its app to people.
    Isn't the Strava App free? I know I didn't pay for it, maybe I got it on a free weekend or something.

    Edit: Sorry, hadn't gotten through the whole thread to see this was already covered.

    FWIW, when I ride I typically have both the Strava cycling app on my iphone4 as well as my Garmin Edge 500 running. They are usually less than .1 of a mile difference between them at the end of a 20 - 25 mile ride. The reason I use the Strava app is the convenience of riding then immediately synching my ride to Strava.com without having to go to my computer, download my files, etc.

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    Good call Strava....I bought my speed sensor to be more accurate. If it was removed from the data collection, I would be annoyed.

    How about emailing people who have their stuff un-calibrated?

  29. #29
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    What bugs me is when you complete a segment, then check the times to see that other people took a totally different route over that section of trail and still had their times added to the segment. There's a segment near me where almost every person took a different route, but all of our times are still compared against eachother.

  30. #30
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    Quote Originally Posted by RaptorTC View Post
    What bugs me is when you complete a segment, then check the times to see that other people took a totally different route over that section of trail and still had their times added to the segment. There's a segment near me where almost every person took a different route, but all of our times are still compared against eachother.
    Segments are still calculated weird. One of our trails is set up as a whole segment on Strava. Even though my average for the ride is 12.5 the segment time is only 11.0 MPH. I don't know how that is possible.

    Mountain Bike Ride Profile | Fisher Farm near Davidson | Times and Records | Strava

    I can hammer all I want to but my times are still unrealistically slow on Strava segements.

  31. #31
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    There is a helpful Knowledge Base article on Segment Matching Issues on the Strava Support site - It may help answer your questions about bad segment matching for loops and similar segments. Click on "Support" in the footer of any Strava page, then find the "Segments" section of our Knowledge Base.

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    Kudo's to Strava for the good customer support and being on this forum. It's a great product. Keep up the good work!
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    Did a ride with another guy and we both tracked the ride with iPhones. I have the free Strava and I think he has the Premium service. We did exactly the same ride. I recorded 34km and he recorded 27km. That's a crazy difference. Looking at the maps, they were'n't that different. Although one section had me riding right thru a lake while his was álong the lake. Strange...

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    Quote Originally Posted by aizu1 View Post
    Did a ride with another guy and we both tracked the ride with iPhones. I have the free Strava and I think he has the Premium service. We did exactly the same ride. I recorded 34km and he recorded 27km. That's a crazy difference. Looking at the maps, they were'n't that different. Although one section had me riding right thru a lake while his was álong the lake. Strange...
    Sounds like it's your GPS data on the two iphones being different...that wouldn't be Strava's fault.

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    Strava has updated their processing again. - Strava does a different post-processing of your "moving time" vs. "resting time" than what will be displayed on your Garmin. This is not based on your DISTANCE but is based on your GPS coordinates, and is determined when Strava detects that you are "moving" or "stationary", meaning that you are not making significant forward progress. This can affect your overall average speed when compared to Garmin, especially if we interpret different moving time than Garmin. It is important to know that Strava is consistent across all data in this calculation, so even if Garmin says something different, Strava is just as "correct" in our own calculations.*

    - Lastly, there has been an update to how we calculate your Distance on Strava (I will update the Knowledge Base article on this). When you upload your Garmin data, Strava runs a clean-up code to remove and fix any GPS outliers in your data - meaning GPS points that are bad, inaccurate, or jump far away from where you really were. This improves the quality of your Garmin data. If (and only if) we detect such outliers, the "fix" includes resetting your Garmin's distance based on GPS coordinates, thus overriding your Garmin's native distance data. We are working on reviewing this automatic fix, as we understand how important displaying distance data from a speed/cadence sensor is to our users. So, please follow these instructions as a WORKAROUND in the short term:

    1. Start a new support ticket, titled 'Revert Distance'

    2. Include all affected URLs in the ticket body

    3. Your distance data for those included URLs will be reverted to your Garmin device's distance readings.*

    No wonder my distances were getting screwy.

  36. #36
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    Still waiting on that trackpoint interpolation roll-out....
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  37. #37
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    Quote Originally Posted by PainkillerSPE View Post
    I liked the segments and competition on Strava. But with this screw up, I'm going back to Garmin Connect.

    My road rides are pretty accurate but my mountain rides are off by 9 miles on some occasions. I use one second recording and a wheel sensor.

    <iframe width='465' height='548' frameborder='0' src='http://connect.garmin.com:80/activity/embed/165738107'></iframe>

    Mountain Bike Ride Profile | 6 Hours of Warrior Creek near Beaver Creek | Times and Records | Strava

    Strava will not embed on this site, but the same ride in Strava comes out to be 45.3 miles and my average is only 9.0 mph. Way off and unacceptable for me especially if you are paying for the service.
    Very interesting. Looking at the map, sometimes you get a difference of 100 feet riding the same trail. My phone creates GPS data poorly, and its better than that. Going on and off the trails (virtually) creates longer distance and significantly higher elevation gains. I can get up to 25% more elevation gain comparing to Garmin readings (on other riders bikes).

  38. #38
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    I feel like the quality of what mobile phone you have has alot to do with it. before i bought an iphone 4 i had the 3g, and my data was really messed up.
    with my 3g the line would be all jagged and not on the road, but with my iphone 4 i can zoom in all the way with satelite map and see where i got off my bike and walked 2 feet to go to the bano, or I can see where I was getting ready for the ride and had to run upstairs to grab a tube or something.
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  39. #39
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    Quote Originally Posted by RaptorTC View Post
    What bugs me is when you complete a segment, then check the times to see that other people took a totally different route over that section of trail and still had their times added to the segment. There's a segment near me where almost every person took a different route, but all of our times are still compared against eachother.
    This is my one beef with Strava. We have a single trail that fans out into three distinct "finishers" of various distance and challenge, but it appears that all three options count as the same segment. I suppose ending the segment before the junction would eliminate the issue, but that would make for a rather boring segment...

    It has occurred as well on shorter segs when riders only hit a small portion of the segment but still show up on the leaderboard (with an incredible time, no less!)

    Not the end of the world, of course...we're still riding and having fun. It just makes for a bigger challenge showcasing the size of your wee wee to the world...

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    Quote Originally Posted by PainkillerSPE View Post
    It use to be pretty awesome, but now they have switched over to just using GPS points to calculate ride data. When my rides start coming in 9 miles under what I actually rode and they take my speed/cadence sensor out of the calculations; I can no longer recommend it as a training tool.

    This was all done to account for the uptick of mobile phone users. So beware of using Strava for now.


    "Strava switched from processing the distance/speed data recorded by the Garmin, to creating our own data set. Basically, right now, we are taking the GPS data in the file, and processing the distance based on the GPS coordinates. So we are calculating the distance between each recorded GPS point and adding them up. This will override any data you may have from a speed sensor, and may even be different that the Garmin's GPS-based "real-time" distance calculation.

    We feel this is the most consistent way to get distance data across all devices, including mobile devices. We understand that the data may be different than what Garmin reports.

    Sorry for the confusion!

    Best,
    Elle
    Strava Support Team"

    Isn't this a benefit? I see this as a plus feature.

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    Quote Originally Posted by light0bike View Post
    Isn't this a benefit? I see this as a plus feature.
    Well this is no longer an issue since Strava went back to using wheel sensor data. To answer your question.

    No it was not a plus feature because your device of choice is usually only collecting a point every 1-5 seconds (it could be longer than that. At the speeds bikes can travel it misses sections of trails such as turns which in the end shortens your ride or your device could have terrible accuracy and your points are off which could add or decrease your mileage and screw up the average MPH. When you have a wheel sensor it's constantly feeding mileage data into your computer and gives you a more accurate number as long as you have it calibrated to your wheel size no matter how inaccurate your gps points are.

  42. #42
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    Just a note here that since Strava relies on the wheel sensor (if present) for total ride distance and speed , this can cause errors if you lose the sensor signal during the ride, or somehow have the wrong wheel size.

    If this happens, you can export from stava to a GPX file, which does not preserve non-GPS speed data, and then re-upload the GPX file to throw out the incorrect speed data.
    The above statements have not been evaluated by the Food and Drug Administration

  43. #43
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    Quote Originally Posted by ghettocruiser View Post
    Just a note here that since Strava relies on the wheel sensor (if present) for total ride distance and speed , this can cause errors if you lose the sensor signal during the ride, or somehow have the wrong wheel size.

    If this happens, you can export from stava to a GPX file, which does not preserve non-GPS speed data, and then re-upload the GPX file to throw out the incorrect speed data.
    I purchased my edge 800 with wheel sensor last month and have been playing around with exporting and importing from strava, garminsync, garminconnect > gpx > strava, strava > gpx > garminconnect. I have found that strava > gpx > strava elevates my original recorded elevation.

    example rides 6 July
    original 20.8km 490m elevation
    from strava gpx 20.6km 552m elevation

    29 June ride
    original 81.5km 488m elevation
    garminsync (bulk) 81.5km 462m elevation
    from strava gpx 80.0km 597m elevation

    15 June
    original 26.2km 1042m elevation
    from strava gpx 25.6km 1335m elevation

    June the sensor was calibrated using a strip of tape around the back wheel as a marker and tape on the ground for the starting point, using two full wheel rotations, wearing my normal riding gear and my standard tire pressures (23/27)
    Early July I recalibrated using 6 wheel rotations, tested 10 times sitting on the saddle to get an average reading as was getting a 25mm variation (properly from my standing start and different loading on the tire starting off). I found if I rode out of the saddle for the 6 wheel rotations, which unweighted the back wheel slightly I would average and extra 80mm distance compared to being seated. Here in NZ we have road odometer markers on some of the main roads to test your vehicles speedometer accuracy, my next step is to hopefully find one close to where I live so I can test how close to the mark I am when riding at my normal pace.
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  44. #44
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    I used the auto-calibrate function, and as long as I rode in a straight line (i.e. on a road) for the first 1 km until it confirmed the wheel size, it gave pretty repeatable results that agreed with google earth distances.

    When I did the roll-out test and put the diameter in manually, it ran a bit high, probably because I wasn't siting on the bike when I did it.
    The above statements have not been evaluated by the Food and Drug Administration

  45. #45
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    That's too simple . Why haven't I tried that
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  46. #46
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    I had played with the GPS I my cell phone a few years ago and ended up buying a simple wheel-driven computer because the GPS was so bad. I got a new-to-me Android phone and started playing with the GPS again. Strava was shortchanging me about 1/2 mile in five.

    Hearing that Strava was screwey, I tried another simple bike-computer app called CycleDroid. Due to rain, my first test was on a paved multipurpose trail. Lots of curves etc -- not at all like what you would find on the road. I was shortchanged only a couple of tenths in 5 miles. Ok, I thought, great! But when I tested it on the trail, I got similar results to what Strava gave me.

    Quote Originally Posted by The Strava people
    When mobile data is synced with our servers from the iPhone or Android App, Strava runs a GPS-based distance calculation on the GPS coordinates, as there is not currently a way to gather data from a speed/cadence sensor from the Strava App.
    Sure there is . When stopping a ride, ask the rider to enter the distance he rode.

    Or, if riding a segment whose length was properly measured, why do you even care what the reported distance is? You know how long the segment is. You know when the rider started and finished and how long he was actually moving if you want to factor out pee breaks. So use Distance over Time to calculate Rate.

    BTW, the ability to tell if you are moving or not seems to not work well. I stopped a few times to take pictures, and I had a lot lower reported speed than the first time I rode the same route and took almost no breaks, even though I rode faster when I was riding the second time.

    Anyway, if you (Strava) are looking for new-user first-impressions, it's a fun app, easy to learn and use. Great idea. I think for road guys it may be the thing. But for mountain biking, it needs work. Besides the distance problem, a lot of segments from popular riding areas are missing or show up intermittently on the map.

    I realize that the problem may well be limitations of GPS technology operating under heavy canopy at slow speeds on really crooked trails, so please take my criticism in that light.

    I have been researching attaching Ant+ stuff to the Android. Apparently you can get a USB-To-Go cable, a USB ANT+ stick, the ANT+ Radio and USB services from the App store, and you are in business. Check it out, Strava.

    Or, they have Bluetooth heart-rate monitors. So get someone to make a Bluetooth interval sensor.

    Edited to add: Check this out!
    http://velocomputer.com/views/index.jsp

  47. #47
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    Just to add my two cents. I am one of the users just using a cell phone and like others have said, I believe it really depends on your device how well strava will work. I will lose gps during storms, lose 3 miles or more in 20 mile rides, and it is now missing segments. Losing/missing segments only started with the last update.
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  48. #48
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    I Can no Longer Recommend Strava.

    Strange, I use a 705 and my Garmin and Strava are usually within .1-.2 km of each other.

  49. #49
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    Not much more to add that several people haven't said. But I recommend using "www.ridewithgps.com" inste a d of strava. They dont mess withyourdaga and the free membershipoffer a lot more services than strava.

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    Quote Originally Posted by xalos1 View Post
    Not much more to add that several people haven't said. But I recommend using "www.ridewithgps.com" inste a d of strava. They dont mess withyourdaga and the free membershipoffer a lot more services than strava.
    Can you elaborate? I find Strava to be an amazing site.

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