P R O G R A M W H E E L S I Z E , U N I T S A N D C H R O N O G R A P H
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P R O G R A M W H E E L S I Z E , U N I T S A N D C H R O N O G R A P H
ENGLISH
M E A S U R E D W H E E L S I Z E
If your wheel/tire size is not one of the pre-programmed sizes, or if you desire absolute accuracy, you may
enter an exact wheel circumference into the system. Use one of the two following methods for measuring
the circumference of your wheel/tire combination.
M E A S U R I N G W H E E L S I Z E U S I N G R A D I U S M E T H O D
The wheel radius method is quick, easy and very accurate.
1. With your bike standing vertically on a flat surface, measure the distance in millimeters from the
center of the front axle or quick release to the floor. If your measurement is in inches, multiply by
25.4 to convert to millimeters.
2. Multiply the measurement in millimeters by 6.28 and enter the resulting number into your computer
using the steps on Page 35.
M E A S U R I N G W H E E L S I Z E U S I N G R O L L O U T M E T H O D
The roll-out method is the most accurate method for determining the circumference of your wheel/tire
combination.
1. On a flat open surface make a mark on your tire and the floor exactly where they meet.
2. Roll your bike forward one full revolution of the front wheel and mark the point on the floor where the
revolution is complete. For maximum accuracy be sitting on the bike while someone rolls you and the
bike forward.
3. Measure the distance from the first mark to the second in millimeters and enter the resulting number
into your computer using the steps on Page 35.
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C Y C L E C O M P U T E R
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