Stava reads Max speed of 51.8Mph

NITR8s
NITR8s Posts: 688
edited May 2012 in Road beginners
On saturdays cycle strava says on one decent I done 51.8Mph, now not having previously beaton 40mph I am a bit dubious if this is correct. Would I have noticed how rediculously fast I was going or not really noticed that much of a difference between 39mph to 51mph.

http://email.strava.com/wf/click?upn=FLdFplb9Rd0LY-2BmLy3OryuEnPQ4oTB4anhNPYw9LQjDFO5Bcq9tE-2FOk0ZUIzI5e0uNA-2BaC4MqODNS9bTRyshEeZ9ayQHYbTRkh1B288YKKNjPRZB3TjhMwZOYuL3Pvl2EUmP7s-2B00vCKjh95eHfheg-3D-3D_-2BPe06-2FbvfIwPZYvDYsJeB0MMrYeyesSGKtFC6GzISssbNM7hFkvMA7VPc8rcxiacsgMWBZoqf2IvcmLBdgwQ4D8mhRA9MALLQShpuH5UxExw2hdvopGRZHg9zLdt6-2FL1lTXL5PxNj0yimJkDmzZNv2C1YHZctpA-2Bj7jlApt4Ynk-3D

Comments

  • slowondefy2
    slowondefy2 Posts: 348
    Strava is a bit wild about calculating max speed. Phone GPS can be inaccurate from moment to moment, and this can cause hugely inaccurate current speeds. This doesn't affect the accuracy of the average speed though, which is generally pretty good.
  • Calpol
    Calpol Posts: 1,039
    I get this with my Iphone also. 48mph on my last run with it - I knew it wasnt right because I didn't crap myself on the way down the hill in question. Hence the reason I now have a Garmin.
  • NITR8s
    NITR8s Posts: 688
    I would assume that although it is not accuate, I must have aleast been doing 45mph+.

    I wonder why it is not accurate though, as the speedometer on a satnav is pretty damn accuarate and it effectivly does the same thing.
  • rick_chasey
    rick_chasey Posts: 75,661
    NITR8s wrote:
    I would assume that although it is not accuate, I must have aleast been doing 45mph+.

    I wonder why it is not accurate though, as the speedometer on a satnav is pretty damn accuarate and it effectivly does the same thing.

    Phone GPS isn't as good, innit? :p.

    There are bits in London which have people going at 900mph.
    _
  • NITR8s
    NITR8s Posts: 688
    Yer but i have cycled the route going the overdirection and not noticed any blips in data.
  • styxd
    styxd Posts: 3,234
    Yes, the difference between 39mph and 52mph is fairly noticeable!
  • majormantra
    majormantra Posts: 2,094
    I have an Edge 500 and I'm fairly sure that Strava has given a higher max speed on occasion. The Garmin is taking speed from the rear wheel but Strava seems to be estimating it from the GPS data, which isn't as accurate.
  • sancho1983
    sancho1983 Posts: 76
    One of my runs last week it said I was doing 78mph - Which I feel is inaccurate.

    Bit annoying though as I purposefully included a reasonable downhill section to see how fast my new toy would take me. But it definitely wasn't 78...

    I'm looking for a Garmin too, I love Strava but I dislike having to take my expensive phone out every time I go out.
  • NITR8s
    NITR8s Posts: 688
    You could always get your self one of these for £45

    http://www.maplin.co.uk/gps-travel-tracker-227620
  • springtide9
    springtide9 Posts: 1,731
    What's the saying...

    Garbage in, garbage out

    Strava is just processing the data you have given it. If the GPS data is not accurate, then Strava's data will also not be accurate.

    And some applications will provide more 'smoothing' of the data to get rid of these inaccuracies, but with the expense of introducing their own inaccuracies due to the smoothing
    i.e. if you want an application to present the most accurate data within the application - if you have inaccurate GPS data you want more smoothing; if you have accurate GPS data less smoothing.

    On a side not - there are a number of thresholds that each of the applications use for specific measurements, and they are not all the same.
    Simon
  • xpc316e
    xpc316e Posts: 43
    I lent a friend my satnav for a car journey to London. Just out of interest, I reset the max speed function before lending it out. When he returned it I checked and discovered he had reached 278 mph in his Vauxhall Vectra. I think it must have had a glitch.
    Riding a Dahon Jetstream P9 folder, a Decathlon Fitness 3 flat-barred road bike, a Claud Butler Cape Wrath MTB, a TW 'Bents recumbent trike, a Moulton-based tandem, and a Scott CR1 Comp road bike.
  • ShutUpLegs
    ShutUpLegs Posts: 3,522
    xpc316e wrote:
    I lent a friend my satnav for a car journey to London. Just out of interest, I reset the max speed function before lending it out. When he returned it I checked and discovered he had reached 278 mph in his Vauxhall Vectra. I think it must have had a glitch.

    Really :?:
  • nferrar
    nferrar Posts: 2,511
    I posted up a ride to both Strava and Garmin Connect a couple of days ago (recorded on an Edge 500), Connect showed my max speed as 42mph and Strava 53mph and I know it wasn't much over 40mph as I was on unfamiliar roads and not going for it on the descents. No clue where Strava is getting it's figures from considering it's been given the same data...
  • springtide9
    springtide9 Posts: 1,731
    nferrar wrote:
    I posted up a ride to both Strava and Garmin Connect a couple of days ago (recorded on an Edge 500), Connect showed my max speed as 42mph and Strava 53mph and I know it wasn't much over 40mph as I was on unfamiliar roads and not going for it on the descents. No clue where Strava is getting it's figures from considering it's been given the same data...

    Read my post above :) The data is the same... but the processing is different.
    Simon
  • snoopsmydogg
    snoopsmydogg Posts: 1,110
    Had a similar issue last night, quick ride out and only one sort of descent (110ft drop in about .2/.3 mile). The computer on the bike never went above 36 yet strava claims a max of 42mph.

    Once I uploaded to the pc and checked the data on the strava site there was nowhere that I went above 36 yet it still claims a max speed of 42. :?
  • tonyf34
    tonyf34 Posts: 194
    This is the problem with newer technolgies, there's more things to go wrong and infinitely more variables regarding data & the processing as mentioned. At least with a simple wheel circumference based bike comp (that you sat on & wheeled to be truly accurate) there's little to go wrong aside from batteries running out.
    I've had my Raleigh Echowell on the commuter/touring bike for over 10 years and it's never failed once come rain or shine, it did finally struggle at -14 though ...lol
  • NITR8s
    NITR8s Posts: 688
    snoopsmydogg wrote:
    Had a similar issue last night, quick ride out and only one sort of descent (110ft drop in about .2/.3 mile). The computer on the bike never went above 36 yet strava claims a max of 42mph.

    Once I uploaded to the pc and checked the data on the strava site there was nowhere that I went above 36 yet it still claims a max speed of 42. :?

    Crop you ride slightly and see if it makes a difference, I cropped my ride and afterwards it showed the section I supposely did 52 mph on.
  • Wirral_paul
    Wirral_paul Posts: 2,476
    I've managed 50mph recently and its b!oody fast. Strangely Strava had me at only 46mph maximum - opposite to the usual over-estimating that it usually does for me and everyone else as shown above.

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