Precise Calibration.
To take full advantage of the precision of your Cyclometer 45tt, mea-
sure the tire's ‘rolling circumference’ by the following method: Mark the ground under the valve
stem when the stem is at its lowest point. Get on the bicycle and have a helper push you in your
normal riding position until the valve stem returns to its lowest point. Take care that the tire
travels in a straight line. Mark below the stem again, then measure the distance in inches between
the marks. This measurement is your calibration number. Tire pressure can have a big effect on
your measurement, so be sure to inflate your tires to your usual riding pressure. Recording the
measurements for different bicycles and wheels below will save you the trouble of remeasuring in
the future.
Bike/Wheel___________________ Calibration #:__________________________________
Bike/Wheel___________________ Calibration #:__________________________________
TOTAL DISTANCE SETUP.
If you want to adjust total distance,
hold the left button when ‘mi’ or ‘km’ is displayed. Total distance ap-
pears. Adjust the blinking digit with the left button, then go to the next
digit with the right button. After adjusting all digits, exit to calibration
with the right button.
When you install a new battery, accumulated total distance is lost. You
can reenter this distance and you can also transfer distance from an-
other computer by adjusting the total distance accumulated on your
Cyclometer 45tt.
If you want to use the Total Distance function as a second Trip Distance
function, you can adjust total distance to zero at the beginning of a
week, month, or multi-day tour to record weekly, monthly, or tour miles.
CALIBRATION.
Find the calibration number that matches your tire
size from the table, or measure tire circumference by the precise calibra-
tion method. Calibration by the table will give acceptable precision for
speed, but if you want to take advantage of your Cyclometer 45tt's ability
to measure distance with precision to 0.01 mile, you must measure your
tire circumference.
When the arrow at the lower right of the display points up, pressing the
left button increases the calibration number. When it points down, the
number decreases. Holding the left button increments rapidly through
the numbers. At the correct number, press the right button to go to
sleep setup.
SETUP STEPS 1a & 2
11
Calibration Table.
Tire sizes are molded into tire sidewalls. This table is based on popular
tire brands and assumes recommended inflation pressure and a rider weight of 165 lbs. (75 kg).
Rear tires carry more weight than front, and this makes them smaller. If you use a rear mount,
subtract .35" or 9 mm from the numbers below. There are many variables that affect tire size, so
the table numbers are only approximate. To account for your unique combination of weight, tire
pressure, and tire model, measure your tire circumference.
SETUP-PRECISE C
ALIBRA
TION
12
Calibration Number
Tire Size
Miles
Km
20 x 1.75
60.16 in
1528
24 x 1
69.02
1753
600 tubular
69.25
1759
650 tubular
75.95
1929
26 x 1
75.32
1913
26 x 1.25
76.89
1952
26 x 1.5
78.19
1986
Calibration Number
Tire Size
Miles
Km
26 x 1.95/2.0
80.51
2045
26 x 2.1
80.95
2056
26 x 1
3
/
8
81.42
2068
700 tubular
82.13
2083
700 x 20
81.93
2081
700 x 23
82.17
2087
700 x 25
82.32
2091
Calibration Number
Tire Size
Miles
Km
700 x 28
82.52
2096
700 x 32
83.31
2116
700 x 38
85.00
2159
27 x 7/8
81.77
2077
27 x 1
82.91
2105
27 x 1 1/8
83.58
2123
27 x 1 1/4
84.33
2142
D
mi
D
mi
mi
Step 1a
Step 2
