III. Basic Measurement

    Align the zero graduation on the rim accurately with the starting point on the ground and roll the wheel forward about 20 degrees until a magnet can be seen at the top of the wheel. (For the BC 800 and Targa manufactured in 2002 and for the Protégés in special single-magnet mode, rotate the wheel backward rather than forward 20 degrees.) Zero the trip meter and ride continuously until the desired revolutions are registered on the meter or until about one revolution before the desired finish. Stop the bicycle immediately and roll forward slowly until the desired reading is indicated on the wheel rim or until the wheel is aligned with the desired finish line. Rolling backward or going through the zero point again after the stop is no problem providing the meter reading has been noted at the stop and this is appropriately decremented or incremented. Repeat the whole process for measurements beyond the first finish point.

    Avoid stopping the bicycle during measurement, but if forced to do so, check that a magnet has rotated about ten degrees beyond its peak wheel position before releasing the brake. If a magnet has not reached this position, release the brake and instantly move the wheel forward to get a magnet into this position. The wheel can then rock 20 degrees backwards and forwards without generating spurious impulses or affecting the accuracy of measurement.

    To check for lost or spurious impulses to the meter at any time but particularly at the start of first measurement of the day, check the synchronization of the meter with the zero point on the wheel. The instant that the zero point reaches its lowest point, the reading on the meter should increment by one.