X.  Half-Marathon and Longer Distances

     This section need only concern the rare measurer who plans to measure a distance of  10,000 revolutions or more (approximately equivalent to a half-marathon or more) through a continuous ride. For this measurement the meter will display 9999 revolutions for two revolutions and the measurer should add one to all displays after the first one. Similarly, the meter will display 19998 revolutions for two revolutions and the measurer should add two to all displays after the first one.

     What happens is that although through the basic mode of operating in this report the computer seems to increment trip distance by 10 meters for every revolution, it actually only increments 9.999 meters. The following table for the first nine revolutions makes clear what happens:

After 9999 revolutions nothing remains in trip memory that is undisplayed, and at 10,000 revolutions the computer does not change the display but simply puts 9.999 meters into memory. At 10,001  the computer resumes incrementing with a display of 100.00.

     The above correction to the display can be avoided if the circumference in computer memory is set to 5000 and a second magnet is placed diametrically opposite the first on the same side of the wheel. Note that in this mode of operation after aligning with the start, the wheel must be rolled forward not backward before zeroing the meter. Care will have to be taken to avoid rolling back unintentionally near a rim reading of 0.5 as well as 0, but no correction to the display need be made no matter how long the continuous ride.