Trek Bicycle Computer - Manual (Page 30)

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28 Advanced features
To measure rollout for wheel size
Table 1 approximates the circumference of
each tire size. Instead of using an approxima-
tion, you can measure the actual circumfer-
ence of your wheel. You need a helper, your
bike, and a smooth floor with enough room
to roll the bike about 7 feet (245 cm) in a
straight line.
1. With the valve stem of the front wheel directly
over the floor Figure 22), sit on the bike.
2. Have your helper mark the floor at the valve
stem.
3. While you sit on the bike, have the helper roll
the bike forward one revolution of the wheel, so
that the valve stem is again directly over the floor.
4. Mark the new location of the valve stem.
5. Measure the distance between the marks, in millimeters.
If you can only measure in inches, convert to millimeters by multiplying by 25.4.
6. Use the result to program your computer, following the instruc-
tions on page 25.
Fgure 22- Measurng rollout for
wheel sze
06 Incite ACH 07_13.indd 28 7/14/06 7:26:12 AM