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  1. #1
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    accurate tire size set

    I have a tahoe 2.0 2012 & using a bike computer it's wheel size is :

    26*2.20
    54-559

    but the attached manual doesn't have this size what should I do ?
    Attached Thumbnails Attached Thumbnails accurate tire size set-scanimage001.jpg  


  2. #2
    Trailhead Poseur
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    Measure rollout. Using the valve stem for reference, sit on the bike and ride in a straight line for one complete revolution of the wheel, then measure the distance between the start and finish points. For more accuracy, ride farther (two or three revolutions) and take an average.

    It's the most accurate method anyway, because actual tire circumference will vary depending on tire model, pressure, and bike and rider weight.

  3. #3
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    accurate tire size set

    Quote Originally Posted by peaceful1 View Post
    I have a tahoe 2.0 2012 & using a bike computer it's wheel size is :

    26*2.20
    54-559

    but the attached manual doesn't have this size what should I do ?
    Do a roll out. Been discussed here many, Many, MANY times.
    mtbtires.com
    The trouble with common sense is it is no longer common

  4. #4
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    thanks guys for helping me out just fore making it clear

    when I find out the exact tire circumference what should I do with it?

    it suppose to make a special number in the chart right ?

  5. #5
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    Enter it directly as wheel circumference after adjusting it to the correct measurement asked for (cm or mm).

  6. #6
    Nouveau Retrogrouch SuperModerator
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    accurate tire size set

    Quote Originally Posted by peaceful1 View Post
    thanks guys for helping me out just fore making it clear

    when I find out the exact tire circumference what should I do with it?

    it suppose to make a special number in the chart right ?
    To quote your attached chart: "wheel circumference in mm"
    Clear enough?
    mtbtires.com
    The trouble with common sense is it is no longer common

  7. #7
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    hey! in the top it says "wheel circumference" why I haven't seen that before !

    by the way is the magnet placement important in the accuracy (answered)

    you guys are great I appreciate all the help

  8. #8
    Nouveau Retrogrouch SuperModerator
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    accurate tire size set

    Quote Originally Posted by peaceful1 View Post
    hey! in the top it says "wheel circumference" why I haven't seen that before !

    by the way is the magnet placement important in the accuracy (answered)

    you guys are great I appreciate all the help
    Only in that the magnet needs to properly align with the sensor.
    mtbtires.com
    The trouble with common sense is it is no longer common

  9. #9
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    Quote Originally Posted by shiggy View Post
    Only in that the magnet needs to properly align with the sensor.
    yup. that is all. the sensor is simply a reed switch that only ticks off revolutions. the computer head unit counts those revolutions and converts them to a distance using the wheel circumference.

  10. #10
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    when I ruled out it was 2100 mm but when I calculated with its radius it was 2136 mm

  11. #11
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    Quote Originally Posted by peaceful1 View Post
    when I ruled out it was 2100 mm but when I calculated with its radius it was 2136 mm
    a proper rollout accounts for tire pressure and rider weight compressing the tire as you ride, while using the radius does not.

  12. #12
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    Ride several revolutions and get an average.

    Put a zip tie around your wheel & tire so it marks the ground as you ride -- have also heard of people using a dot of paint.

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