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Additional Cyclecomputer Calibration Procedures - Ascent to Avocet
Original article: https://www.sheldonbrown.com/cyclecom_cal_proc-A.html on sheldonbrown.com
- Reproduced with the permission of John Allen and Harriet Fell — all rights reserved. The version on sheldonbrown.com is authoritative.
- Mirrored: 2026-10-05 · Last update of the original: see original
Our Cyclecomputer database is your starting point when looking for information on cyclecomputers. It links to owner's manuals for most cyclecomputers. Sometimes we had to work without a manual, or have additional information. It's on this page if the brand name begins with an A or B.
Look for similarities in appearance and function when trying instructions for a computer not on our list. Many bicycle computers are rebranded. Please let us know of rebranded models which you have identified.
Old versions of manufacturers' Web sites preserved on the Internet Archive may list older models. A Web search on the make and model, plus "manual" or "instructions" sometimes turns up information posted by an owner. If you have information on a model not covered here, please send it in.
Atech KA-4, 8, 10
- Battery: LR43/186/L1142 1.5 volt
- === Click here for manual as 832 kb jpeg file ===
(Thanks to Joao Marcelo Soares)
Avocet 15
15 and 25 Manual from before 2000-05-01
15 manual from after 2000-05-01
- Battery
- 675 zinc/air 1.4 volt (originally used 675 mercury)
- Miles or kilometers (total reset)
- ;# While in "D" mode (cumulative odometer) press and hold the left button for 12 seconds, until test pattern appears and all data are cleared.
- 4 seconds after releasing, "mi" or "km" appears.
- Use right button to select "mi" or "km".
- Press left button to continue with calibration.
- Entering "Set" mode
- ;# while in "D" mode (cumulative odometer) press and hold the left button for 8 seconds.
- Calibration number will appear, with right digit blinking.
- Changing setting
- ;# Press right button to increase the blinking digit to the correct value.
- Press left button to select next digit...etc.
- Exiting "Set" mode
- Push the left button after all digits have been set.
Avocet 20
Calibration: B (Miles) / F x 0.108 (Km)
- Battery
- 386 silver oxide (originally used 386 mercury)
- Entering "Set" mode
- While in "D" mode (cumulative odometer) press and hold both buttons for two seconds. Calibration number will appear.
- Changing setting.
- Advance numbers with the left button.
- Exiting "Set" mode
- Push the right button.
Avocet 25
15 and 25 manual from before 2000-05-01
25 manual from after 2000-05-01
- Battery
- 675 zinc/air 1.4 volt (originally used 675 mercury)
- Miles or kilometers (Stored speed and distance data are automatically converted to the units chosen.)
- ;# While in "d" mode (daily odometer) press and hold the left button for 6 seconds.
- Release left button when "mi" or "km" appears.
- Use right button to select "mi" or "km".
- Use left button to exit.
- Entering "Set" mode
- ;# while in "D" mode (cumulative odometer) press and hold the left button for 4 seconds.
- Calibration number will appear.
- Release left button, then press and hold it again for 4 seconds until the right digit blinks.
- Changing setting
- ;# Press right button to increase the blinking digit to the correct value.
- Press left button to select next digit...etc.
- Exiting "Set" mode
- Push the left button after all digits have been set.
Avocet 30
- Battery
- 386 silver oxide (originally used 386 mercury)
- Entering "Set" mode
- While in "D" mode (cumulative odometer-"D" will be flashing) press and hold both buttons for three seconds. Calibration number will appear.
- Changing setting
- Advance numbers with the left button. There are two ranges of numbers, from 100 to 299. One range is for miles ("mi" shows in lower right corner) and one for kilometers ("km" shows in lower left corner.
- Exiting "Set" mode
- Push the right button.
- User notes
- short push on right button selects speed, trip distance or stopwatch. holding right button in speed mode gives maximum speed; in trip distance mode, gives total distance; in stopwatch mode, gives time of day.
- To set the clock
- Go to the clock function (the secondary time function) and press both buttons. The hour digits will flash. Advance the hours with the left button. At the correct hour press the right button and the minutes will flash. Advance the minutes with the left button. At the correct minute press the right button to complete setup.
Avocet 31
- Battery
- 675 zinc/air 1.4 volt (originally used 675 mercury)
- Entering "Set" mode
- While in "D" mode (cumulative odometer) press and hold both buttons for two seconds. Calibration number will appear.
- Changing setting
- Advance numbers with the left button. There are two ranges of numbers, from 100 to 299. One range is for miles ("mi" shows in lower right corner) and one for kilometers ("km" shows in lower left corner.
- Exiting "Set" mode
- Push the right button.
- User notes
- short push on right button selects speed, trip distance or stopwatch. holding right button in speed mode gives maximum speed; in trip distance mode, gives total distance; in stopwatch mode, gives time of day.
Avocet 35
Calibration: A (Miles) / F (Km)
- Battery
- 675 zinc/air 1.4 volt (originally used 675 mercury)
- For models 35 and 45, total reset is recommended before battery installation.
- For total reset, hold both buttons down for 35 seconds with battery out.
Avocet 40
- Battery
- 675 zinc/air 1.4 volt (originally used 675 mercury)
- Entering "Set" mode
- Press and hold both buttons for 5 seconds.
- Changing setting
- ;# Left button selects miles/kilometers.
- Right button goes to wheel calibration mode.
- Left button raises or lowers calibration value, depending on the position of the arrow on the right of the display.
- Right button goes to cadence select mode.
- Left button selects cadence mode ("RPM" in display). Most 40s do not have the cadence feature, so this mode should not be activated.
- Right button goes to clock-set mode.
- Left button selects 12 hour or 24 hour clock.
- Right button goes to hour-set mode.
- Left button selects hour.
- Right button goes to minute-set mode.
- Left button selects minute.
- Exiting "Set" mode
- push the right button.
Avocet 45, 45tt
- Battery
- 675 zinc/air 1.4 volt (originally used 675 mercury)
- For models 35 and 45, total reset is recommended before battery installation.
- For total reset, hold both buttons down for 35 seconds with battery out.
- Entering "Set" mode
- Press and hold both buttons for 8 seconds, all segments of display will turn on, continue holding both buttons, then release when "mi" or "km" appears. This does not reset stored data.
- Changing setting
- ;# Left button selects miles/kilometers.
- Right button goes to odometer mode, units digit.
- Left button raises units digit of odometer setting.
- Right button goes to odometer mode, next digit.
- Left button raises next digit of odometer setting...
- Right button goes to wheel calibration mode.
- Left button raises or lowers calibration value, depending on the position of the arrow on the right of the display.
- Right button goes to cadence select mode.
- Left button selects cadence mode ("RPM" in display).
- Right button goes to sleep select mode.
- Left button selects sleep mode. This is used if you are putting the unit in storage for more than two months.
- Right button goes to clock-set mode.
- Left button selects 12 hour or 24 hour clock.
- Right button goes to hour-set mode.
- Left button selects hour.
- Right button goes to minute-set mode.
- Left button selects minute
- Exiting "Set" mode
- push the right button.
Avocet 50
- Battery: two 386 silver oxide 1.5 volt.
- When installing batteries in the Cyclometer 50 use this special double insert procedure:
- Insert both batteries.
- Remove one battery and leave it out for 15 seconds.
- Reinsert the battery you removed. The unit will then go into calibration mode.
- To reach setup with a battery already in the unit, press and hold down both buttons 5 to 8 seconds. After all display segments show briefly the unit goes into setup. Move through the 5 setup functions by pressing the right button.
- Choose or English and metric units with the left button.
- In wheel size calibration, the default of 83.45 (English) or 2120 (metric) shows, and an arrow to the right of the numbers points up then down. Pressing or holding the left button increases or decreases the numbers according to the arrow direction.
- Choose whether trip climb or descent will be recorded by pressing the left button.
- Choose whether cadence will be displayed in the speed function by pressing the left button.
- Set the clock by first advancing the hours with the left button. Press the right button, then advance the minutes with the left button.
This unit doesn't store distance data, but counts revolutions. Accumulated data will change if wheel calibration is changed. Changing from miles to km will yield correct distances in the units concerned.
- When installing batteries in the Cyclometer 50 use this special double insert procedure:

