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Cyclecomputer Calibration Group D

If the model name is highlighted, clicking on it will take you to detailed setting instructions.

Ciclomaster models except CM-37, which uses group C
Magura Velotronic Easy: multiply these values by 2 for km, or by 1.243 for miles.


The setting is the tire's radius in millimeters

See further notes by John Allen if doing a rollout text.


Circumference in centimeters

700 X 44 354
700 X 38 347
700 X 35 345
700 X 32 342
700 X 28 336
700 X 25 335
700 X 23 333
700 X 20 332
27 X 1 3/8 345
27 X 1 1/4 343
27 X 1 1/8 342
27 X 1 340
26 X 2.125 330
26 X 1.9 324
26 X 1.5 312
26 X 1.25 311
26 X 1.0 (559 mm) 305
26 x 1 (650C) 311
Wide 700  C Tubular 338
Narrow 700C Tubular 335
26 X 1 3/8 330
24 305
24 x 1 279
20 X 1.75 (406) 254
20 X 1 1/4 (451) 257
17 x 1 1/4 211
16 x 1 3/8 204

If using a rollout test for greater accuracy, divide the result by 6.2832 (that is, divide by 2 * π). If you are using a calculator, it's easier and more accurate to use the π button!

For the Velotronic Easy, divide by 3.142 (or π) and also do the multiplication for miles. The exact multiplication factor for miles is 2/1.609344.

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