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Cateye cordless 7 accuracy

Started by Brian Wakem · · Last activity · 40 posts · 1,956 views

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UK and Europe
Published
6 January 2005
Last activity
10 January 2005
Original author
Brian Wakem
Posts
40
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  1. I have a couple of regular off-road routes that I do at night on my mountain
    bike. Bizarrely the distance of each course seems to be getting
    progressively shorter.

    Route 1 distances - ordered by date

    17.73m
    17.71m
    17.40m
    17.42m
    17.17m

    Route 2 distances - ordered by date

    12.59m
    12.48m
    12.40m
    12.40m
    12.41m
    12.38m
    12.22m
    12.24m
    12.26m
    12.22m
    12.25m
    12.25m
    12.24m

    I am 100% sure I am doing the same routes each time as I know the woods like
    the back of my hand.

    Anybody have any clue as to what might be going on here?

    --
    Brian Wakem

  2. Brian Wakem said:

    I have a couple of regular off-road routes that I do at night on my mountain
    bike. Bizarrely the distance of each course seems to be getting
    progressively shorter.

    Anybody have any clue as to what might be going on here?

    Tyres getting softer, thereforereducing the effective circumference of
    the wheel, therefore reducing the distance recorded?

    (Goes to do sums)

    Hmm, or possibly the other way round.

    Tim

  3. Brian Wakem said:

    I have a couple of regular off-road routes that I do at night on my mountain
    bike. Bizarrely the distance of each course seems to be getting
    progressively shorter.

    Route 1 distances - ordered by date

    17.73m
    17.71m
    17.40m
    17.42m
    17.17m

    Route 2 distances - ordered by date

    12.59m
    12.48m
    12.40m
    12.40m
    12.41m
    12.38m
    12.22m
    12.24m
    12.26m
    12.22m
    12.25m
    12.25m
    12.24m

    I am 100% sure I am doing the same routes each time as I know the woods like
    the back of my hand.

    Anybody have any clue as to what might be going on here?

    You are cutting the corners tighter.
    You are going faster so less low speed wobble.
    You are pumping the tyres up.
    As the planet cools down it is shrinking.

    ...d

  4. Quoted message said:

    (Goes to do sums)

    Hmm, or possibly the other way round.

    What about rider getting lighter?

    Either recalibrate cycle computer from time to time or eat more pies.

  5. Brian Wakem said:

    I have a couple of regular off-road routes that I do at night on my mountain
    bike. Bizarrely the distance of each course seems to be getting
    progressively shorter.
    Anybody have any clue as to what might be going on here?

    Are you travelling at or near the speed of light?

    --
    Amazon: "If you are interested in 'Asimov's I-Robot',
    you may also be interested in 'Garfield - The Movie'.
    ... erm, how do they figure that one out?

  6. Richard Bates said:
    Brian Wakem said:

    I have a couple of regular off-road routes that I do at night on my mountain
    bike. Bizarrely the distance of each course seems to be getting
    progressively shorter.
    Anybody have any clue as to what might be going on here?

    Are you travelling at or near the speed of light?

    "No, but I know where I am."

    Tim

  7. in message <[email hidden]>, Brian Wakem

    (') said:

    I have a couple of regular off-road routes that I do at night on my
    mountain
    bike. Bizarrely the distance of each course seems to be getting
    progressively shorter.


    [Snip: reducing distances]

    Quoted message said:


    I am 100% sure I am doing the same routes each time as I know the
    woods like the back of my hand.

    Anybody have any clue as to what might be going on here?

    You're picking better lines and riding more smoothly?

    --
    [email hidden] (Simon Brooke) http://www.jasmine.org.uk/~simon/

    ;; no eternal reward will forgive us now for wasting the dawn.
    ;; Jim Morrison

  8. "Brian Wakem" <[email hidden]> wrote in message
    news:[email hidden]...

    Quoted message said:

    I have a couple of regular off-road routes that I do at night on my
    mountain
    bike. Bizarrely the distance of each course seems to be getting
    progressively shorter.

    Route 1 distances - ordered by date

    17.73m
    17.71m
    17.40m
    17.42m
    17.17m

    Route 2 distances - ordered by date

    12.59m
    12.48m
    12.40m
    12.40m
    12.41m
    12.38m
    12.22m
    12.24m
    12.26m
    12.22m
    12.25m
    12.25m
    12.24m

    I am 100% sure I am doing the same routes each time as I know the woods
    like
    the back of my hand.

    Anybody have any clue as to what might be going on here?

    --
    Brian Wakem

    When the battery runs down the accuracy gets iffy. Is it likely that the
    battery might be running down? Try switching the batteries, in the sending
    and receiving units to see if that has any effect. I found when the battery
    in the sender was no longer working it was still perfectly good enough for
    the receiver so I just switched the batteries round. Also found that the
    readings became very iffy in the last few rides before the sender battery
    gave up the ghost.

    Cheers,
    Dave

  9. Brian Wakem said:


    Anybody have any clue as to what might be going on here?

    The tyre pressure - and hence the circumference - is not constant?

  10. Brian Wakem said:

    I have a couple of regular off-road routes that I do at night on my mountain
    bike. Bizarrely the distance of each course seems to be getting
    progressively shorter.

    Quoted message said:

    I am 100% sure I am doing the same routes each time as I know the woods like
    the back of my hand.

    Anybody have any clue as to what might be going on here?

    You're wearing a rut in the route, bypassing some of the curvature of
    the Earth.

    Unless...does your route cross between two tectonic plates?

    --
    Mark.
    http://tranchant.plus.com/

  11. Brian Wakem said:

    I have a couple of regular off-road routes that I do at night on my mountain
    bike. Bizarrely the distance of each course seems to be getting
    progressively shorter.

    Route 1 distances - ordered by date

    17.73m
    17.71m
    17.40m
    17.42m
    17.17m

    Route 2 distances - ordered by date

    12.59m
    12.48m
    12.40m
    12.40m
    12.41m
    12.38m
    12.22m
    12.24m
    12.26m
    12.22m
    12.25m
    12.25m
    12.24m

    I am 100% sure I am doing the same routes each time as I know the woods like
    the back of my hand.

    Anybody have any clue as to what might be going on here?

    I don't think these things are guarenteed to be accurate to that amount
    so it wouldn't surprise me if thats just the way it is inside the
    devices. My best gusess would be the performance of the device including
    its batteries changing with the temperature/humidity etc. I'd expect to
    pay alot more money than we do for electronic devices that are
    consistent to a hand full of yards everytime. Fit a third wheel with
    clicks to be more consistent if you really care.

  12. Brian Wakem composed the following;:

    Quoted message said:

    I have a couple of regular off-road routes that I do at night on my
    mountain bike. Bizarrely the distance of each course seems to be getting
    progressively shorter.

    Route 1 distances - ordered by date

    17.73m
    17.17m

    That's about, rough approximation, a 0.1 % difference in distance, over 17
    miles, which is bloody good accuracy for a cycle computer, I'd say. I'd also
    say you're probably picking slightly tighter lines, possibly also, as you
    get to know the route better, going faster with less 'wobble', which
    obviously decreases the distance travelled by the front wheel by a small
    amount.

    Quoted message said:

    Route 2 distances - ordered by date

    12.59m
    12.24m

    I'd say similar to the first route, again bugger all change in percentage
    terms of the whole distance covered, and such a small distance change might
    easily be explained as above.

    You don't say how long you've been travelling the route, but if you've only
    recently started 'logging' it, then maybe, over a much longer timeframe, the
    distance will tend to settle down to an optimum level, but that might take
    weeks or more.

    --
    Paul ...
    http://www.4x4prejudice.org/index.php
    (8(!) Homer Rules ... 😉
    "A [censored] is a [censored], no matter what mode of transport they're using."

  13. Mark Thompson said:
    Quoted message said:

    (Goes to do sums)

    Hmm, or possibly the other way round.

    What about rider getting lighter?

    Either recalibrate cycle computer from time to time or eat more pies.

    Even with recalibration you assume that the device IS accurate. Just
    because it says 17.55 miles is no guarantee the distance IS 17.55 miles.
    You need a certified device to compare it against.

  14. "Paul - [censored]" <[email hidden]> wrote in message
    news:[email hidden]...

    Quoted message said:

    Brian Wakem composed the following;:

    Quoted message said:

    I have a couple of regular off-road routes that I do at night on my
    mountain bike. Bizarrely the distance of each course seems to be


    getting

    Quoted message said:
    Quoted message said:

    progressively shorter.

    Route 1 distances - ordered by date

    17.73m
    17.17m

    That's about, rough approximation, a 0.1 % difference in distance, over 17
    miles, which is bloody good accuracy for a cycle computer, I'd say.

    I make it a 3% difference.

    Quoted message said:

    I'd also
    say you're probably picking slightly tighter lines, possibly also, as you
    get to know the route better, going faster with less 'wobble', which
    obviously decreases the distance travelled by the front wheel by a small
    amount.

    Yes tighter lines would go some way to explain the difference.

    Quoted message said:
    Quoted message said:

    Route 2 distances - ordered by date

    12.59m
    12.24m

    I'd say similar to the first route, again bugger all change in percentage
    terms of the whole distance covered, and such a small distance change


    might

    Quoted message said:

    easily be explained as above.

    You don't say how long you've been travelling the route, but if you've


    only

    Quoted message said:

    recently started 'logging' it, then maybe, over a much longer timeframe,


    the

    Quoted message said:

    distance will tend to settle down to an optimum level, but that might take
    weeks or more.

    All these times were logged between Nov 22nd and Jan 6th.

    --
    Brian Wakem

  15. "Mark Tranchant" <[email hidden]> wrote in message
    news:[email hidden]...

    Quoted message said:
    Brian Wakem said:

    I have a couple of regular off-road routes that I do at night on my


    mountain

    Quoted message said:
    Quoted message said:

    bike. Bizarrely the distance of each course seems to be getting
    progressively shorter.

    Quoted message said:

    I am 100% sure I am doing the same routes each time as I know the woods


    like

    Quoted message said:
    Quoted message said:

    the back of my hand.

    Anybody have any clue as to what might be going on here?

    You're wearing a rut in the route, bypassing some of the curvature of
    the Earth.

    Unless...does your route cross between two tectonic plates?

    I'm not aware of any plate boundaries in North East Hampshire!

    --
    Brian Wakem

  16. "Paul Rudin" <[email hidden]> wrote in message
    news:[email hidden]...

    Quoted message said:
    Brian Wakem said:


    Anybody have any clue as to what might be going on here?

    The tyre pressure - and hence the circumference - is not constant?

    But I'd need to be increasing the tyre pressure every time. They'd have
    popped by now! The pressure is fairly constant.

    --
    Brian Wakem

  17. "David Barnes" <[email hidden]> wrote in message
    news:[email hidden]...

    Quoted message said:

    When the battery runs down the accuracy gets iffy. Is it likely that the
    battery might be running down? Try switching the batteries, in the sending
    and receiving units to see if that has any effect. I found when the


    battery

    Quoted message said:

    in the sender was no longer working it was still perfectly good enough for
    the receiver so I just switched the batteries round. Also found that the
    readings became very iffy in the last few rides before the sender battery
    gave up the ghost.

    The device is only 6 or 7 weeks old so I doubt the battery is low.

    --
    Brian Wakem

  18. "Simon Brooke" <[email hidden]> wrote in message
    news:[email hidden]...

    Quoted message said:

    in message <[email hidden]>, Brian Wakem

    (') said:

    I have a couple of regular off-road routes that I do at night on my
    mountain
    bike. Bizarrely the distance of each course seems to be getting
    progressively shorter.


    [Snip: reducing distances]

    Quoted message said:


    I am 100% sure I am doing the same routes each time as I know the
    woods like the back of my hand.

    Anybody have any clue as to what might be going on here?

    You're picking better lines and riding more smoothly?

    Yes this is the best explanation I could come up with, but a difference of
    0.56 miles seems excessive to me. It's not like I was learning the route as
    I have run 1000's of miles on these trails before I started cycling.

    --
    Brian Wakem

  19. "David Martin" <[email hidden]> wrote in message
    news:[email hidden]...

    Quoted message said:

    On 6/1/05 8:40 pm, in article [email hidden], "Brian


    Wakem"

    Quoted message said:
    Quoted message said:

    I have a couple of regular off-road routes that I do at night on my


    mountain

    Quoted message said:
    Quoted message said:

    bike. Bizarrely the distance of each course seems to be getting
    progressively shorter.

    Route 1 distances - ordered by date

    17.73m
    17.71m
    17.40m
    17.42m
    17.17m

    Route 2 distances - ordered by date

    12.59m
    12.48m
    12.40m
    12.40m
    12.41m
    12.38m
    12.22m
    12.24m
    12.26m
    12.22m
    12.25m
    12.25m
    12.24m

    I am 100% sure I am doing the same routes each time as I know the woods


    like

    Quoted message said:
    Quoted message said:

    the back of my hand.

    Anybody have any clue as to what might be going on here?

    You are cutting the corners tighter.

    Probably.

    Quoted message said:

    You are going faster so less low speed wobble.

    Faster yes, but I wasn't going that slow enough to wobble to start with.

    Quoted message said:

    You are pumping the tyres up.

    No.

    --
    Brian Wakem

  20. "Mark Thompson" <[email hidden]> wrote in message
    news:[email hidden]...

    Quoted message said:
    Quoted message said:

    (Goes to do sums)

    Hmm, or possibly the other way round.

    What about rider getting lighter?

    My weight had increased from 10st 9lb before I started cycling to 11st 2lb.
    Now that I have started running again (I started cycling due to a running
    injury) I am back down to 10st 12lb and the routes are still getting
    shorter.

    Quoted message said:

    Either recalibrate cycle computer from time to time or eat more pies.

    I shall measure the circumference of the front wheel again and see if it
    different from what I originally inputted into the cateye.

    --
    Brian Wakem

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