Roll Out Method
The roll out method will provide the most
accurate computer calibration accounts for
variables such as inflation pressure, rim
width and rider weight.
1. Extend a tape measure out to 3000mm
(120 inches) and lock it in place.
2. With your tire inflated to its proper pres-
sure, place the valve at the 6:00 position
(at the bottom) directly over the start of the
measuring tape.
3. Roll the wheel one complete revolution
until the valve stem is again at the 6:00
position. Read the tape directly under the
valve and note the distance in millimeters.
(To convert inches to millimeters, multiply
inches by 25.4) . This number represents
your tire circumference in millimeters.
Programming the circumference
The tire circumference (in millimeters) will be
flashing when you are in circumference pro-
gramming mode. Use the right button to
scroll up and the left one to scroll down.
Each push of the side button will change the
circumference one millimeter. Hold the right
or left button to scroll through the digits rap-
idly. When the desired selection is displayed,
press a side button and the top button simul-
taneously to enter the programmable
odometer mode.
7
The hour and minute digits will now
begin flashing. Again, use the right button to
scroll up and the left one to scroll down.
Each push of the side button will change one
minute. If either of the side buttons is held
down it will cause the time to scroll up or
down rapidly. When the desired selection is
displayed press a side button and the top
button simultaneously to enter the wheel
Circumference selection mode.
5. Wheel Circumference Selection
To set the circumference for the tires you
are using, you can either use the table below
to obtain an approximate tire circumference
or measure your actual tire circumference
by the roll-out method.
Specialized Tire Size Chart
SBC
20 X 1.8
1589
SBC
24 X 1.8
1893
SBC
26 X 1.0
1924
SBC
26 X 1.0
1962
SBC
26 X 1.25
1980
SBC
26 X 1.4
2010
SBC
26 X 1.5
2054
SBC
26 X 1.95
2061
SBC
20 X 2.0
2567
SBC
650 X 20
1930
SBC
700 X 20
2100
SBC
700 X 23
2113
SBC
700 X 38
2220
Generic Tire Size Chart
This chart is for non-Specialized tires
26 X 1.75
2140
26 X 2.0
2074
26 X 2.1
2090
650C X 20
1945
700C X 26
2124
700C X 38
2170
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A
M
DST ODO
Wheel
Circumference
Stem
Roll Forward