odometer wheel size help

[newuser]

I am trying to fit an odometer but am not sure of the wheel size chart I've been given in the oh so un-helpful manual.

My bike tyre reads 42 - 622 (700 x 40c - 26 x 1 5/8ths)

So I've figured out that the wheel is 700mm from tip to tip and that is also 26 inches.

The chart that comes with the Sigma 906 odometer isn't very clear. It's multi lingual and offers no explanation (nor does their website, nor can I find anything on google) I am sure I made a mess of my last odometer and I'd like to get this one accurate. So please help.

The chart seems to be divided up into 3 columns. The closest match is
column 1| column 2 | column 3 (shows kmh mph)
40 - 622 | 700 x 40c| 2224

So as an experiment I entered 2224 into my Odometer.

Is that right?
Out of interest, what do all those numbers mean anyway?

Thanks.

 

[threefingerjoe]

The 2224 is the circumference of your tyre, in mm. Different makes and models of tyres vary greatly in actual size. The best way to find the number to enter in your computer, is to use the "rollout" method.

1. Be sure your tyres are pumped up to whatever pressure you plan to run.
2. Place your bike with the valvestem, or some other mark, directly down, on the floor. Make a mark on the floor next to the valve stem.
3. Sit on the bike. Hold the bars so that they are facing straight forward. Roll the bike forward, exactly 1 revolution of a wheel, until that valvestem, or whatever mark you used, is back at the floor.
4. Make a new mark on the floor, where the valvestem landed, after that one revolution.
5. Measure the distance between your first mark on the floor (starting point) and your second mark on the floor (ending point). This distance, in millimeters, is the number that you enter into the computer/odometer.

 

[jay clock]

Agreed, measure it yourself as above. It only takes a minute or two. Most do require the circumference to be entered in mm. It then uses its brain to know that each time the magnet passes the sensor the wheel has travelled that distance.

 

[bonj2]

The 2224 is the circumference of your tyre, in mm. Different makes and models of tyres vary greatly in actual size. The best way to find the number to enter in your computer, is to use the "rollout" method.

1. Be sure your tyres are pumped up to whatever pressure you plan to run.
2. Place your bike with the valvestem, or some other mark, directly down, on the floor. Make a mark on the floor next to the valve stem.
3. Sit on the bike. Hold the bars so that they are facing straight forward. Roll the bike forward, exactly 1 revolution of a wheel, until that valvestem, or whatever mark you used, is back at the floor.
4. Make a new mark on the floor, where the valvestem landed, after that one revolution.
5. Measure the distance between your first mark on the floor (starting point) and your second mark on the floor (ending point). This distance, in millimeters, is the number that you enter into the computer/odometer.

or a few, then divide it by how many you do, for more accuracy. (as long as your tapemeasure/measuing device will allow)

 

[newuser]

cheers