Help setting up cycle computer

Bungee8
Bungee8 Posts: 2
edited May 2009 in MTB beginners
I've just got a wireless cycle computer, and need to setup wheel circumference settings for it.
The bike is a GT Aggressor XC2 with 26" wheels, but the manual for the computer is a bit confusing, with lots of different settings like:

26 X 1
26 X 1.5
26 X 1,6
26 X 1.75 X 2
26 X 1.9
26 x 2.0
26 x 2.2
26 X 1 3/8
26 X 3/4

I assume its the tyre size, but it doesn't have a setting for this bikes 2.3" ones.

Any ideas :oops:

Comments

  • Si78
    Si78 Posts: 963
    hi

    Measure the total diameter of the wheel and tyre in millimeters, then multiply it by 3.14 (Pi).
    This will give the circumference of the wheel and tyre in millimeters. should be a 4 figure number. Enter this into the computer.

    hope that helps

    Si
    Why has my sig been removed by the admins???
  • Andy B
    Andy B Posts: 8,115
    best way is to mark the tyre, with say a bit of masking tape & a pen mark on it

    then stick some masking tape on the floor with a pen mark on it

    line the two marks up so the pen mark on the tyre lines up with the one on the floor

    roll the bike forwards in a straight line & mark the spot on the floor where the mark on the tyre is at the bottom again.

    Double check it, measure between the two lines on the floor & you have the correct number to enter into the computer (might be in inches or in mm)
    2385861000_d125abe796_m.jpg
  • xtreem
    xtreem Posts: 2,965
    [b]Andy_B[/b] wrote:
    ...to enter into the computer (might be in inches or in mm)
    If it's a cheap computer then he probably doesn't have that option.

    So mate if you can't do what Andy_B said, just set it to 26 x 2.2.
    Some 2.2 tires are bigger then 2.3 of other manufacturer, so more precision
    is achieved if you can enter the tire circumference in inches or mm as Andy_B sugested.
    NS Bikes Eccentric Alu custom - 2016
  • Andy B
    Andy B Posts: 8,115
    Xtreem wrote:
    [b]Andy_B[/b] wrote:
    ...to enter into the computer (might be in inches or in mm)
    If it's a cheap computer then he probably doesn't have that option.
    usually depends if you choose MPH (inches) or KPH (millimetres) when you set it up, but not always.
    2385861000_d125abe796_m.jpg
  • tri-sexual
    tri-sexual Posts: 672
    its always best to do as andy b suggest even if the instructions include your tyre size, you will be surprised at the variations in the wheel/tyre circumference between different tyre makers due to the profile height of the tyre.
    to be super accurate however its important to pump the tyres to the correct pressure and sit on the bike before rolling along the line then measure one revolution of the wheel.

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