ALTIMETER 50
RPM
ALTIMETER 50
ALTIMETER 50
A
ALTIMETER 50
ENGLISH
ALTIMETER 50
Setup.
When the batteries are installed all display segments show briefly, then the unit goes through a 10-second
countdown before going into the setup sequence. Setup can also be reached from any function by holding both buttons
down more than eight seconds.
S E T U P S E Q U E N C E
Press the right button to
move from one setup
function to the next.
WHEEL SIZE CALIBRATION
ENGLISH OR METRIC
CLIMB OR DESCENT
CLICK
CADENCE ON/OFF
CLOCK SET
4.
5.
1.
2.
3.
CLICK
CLICK
CLICK
CLICK
6
S E T U P S E Q U E N C E
Precise Calibration.
To take full
advantage of the unit's precision, meas-
ure the front tire’s “rolling circumfer-
ence” 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. Mark below the stem again, and
measure the distance between the marks.
This measurement is the rolling circum-
ference of the tire and also the precise
calibration number.
Enter this calibration number, then
press the right button to go to the climb
or descent setup.
S E T U P S E Q U E N C E
Calibration Numbers
Number
Number
Tire Size
English
Metric
Tire Size
English
Metric
20 x 1.75
60.13 in
1528
700C tubular
82.12 in
2083
24 x 1
69.00
1753
700 x 20
81.02
2058
24 tubular
69.25
1759
700 x 25
82.13
2086
26 tubular
75.93
1929
700 x 28
82.52
2096
26 x 1
75.31
1913
700 x 32
83.23
2114
26 x 1.25
77.44
1967
700 x 35
84.21
2139
26 x 1.5
77.71
1974
27 x 7/8
81.77
2077
26 x 1.9/1.95
80.62
2048
27 x 1
82.92
2105
26 x 2.125/2.2
81.65
2074
27 x 1 1/8
83.58
2123
26 x 1
3
/
8
(3-speed) 81.42
2068
27 x 1 1/4
84.33
2142
Note:
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 150 lbs. (68 kg). If
your tire size is not included, or if you want to account for your particular combination of
weight, tire pressure, and tire brand, measure your tire circumference according to the
precise calibration method. Lowering tire pressure in a 26 x 1.9 mountain bike tire from
80 psi to 40 psi reduces in-use tire circumference by approximately 1 inch or 25 mm.
2. Wheel Size Calibration.
The wheel size
calibration default of 83.45 (English) or 2120 (metric)
shows, and an arrow to the right of the numbers points
up then down. Pressing the left button increases the
numbers one at a time when the arrow points up and
decreases them when the arrow points down. Holding
down the left button increments rapidly through the
numbers. Calibration numbers equal tire circumfer-
ence in either inches or mm. Choose a calibration
number from the table or measure tire circumference.
1. English/Metric Setup.
The display first shows
ENGLISH (feet/miles). Choose METRIC (meters/kilo-
meters) by pressing the left button. Return to English
units by pressing the left button again. Press the right
button to go to wheel size calibration.
mm
mm
ENGLISH
Left button selects English or Metric
WHEEL SIZE CALIBRATION
ENGLISH OR METRIC
Left button increments calibration numbers up
or down depending on arrow direction
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