Calibrated bicycle course measurement

Assembled from 9 blocks · 1 evidence · 11 related

1. Story
2. A road course is certified by riding it on a bicycle fitted with a Jones counter, a geared revolution counter mounted on the front axle. The bicycle is calibrated against a steel-taped calibration course, ridden four times in each direction before and after the measurement, and the working constant is the mean of those rides. The measurer then rides the shortest possible route a runner could legally take — cutting tangents, holding roughly 30 cm from kerbs and boundaries — because that, not the centre line, is the distance the fastest runner will actually cover. Finally the counts-per-kilometre constant is multiplied by 1.001, the short course prevention factor, so that a certified marathon is laid out at about 42.237 km. The bias is deliberate and one-directional: a course may be very slightly long, but must never be short, because a short course silently converts every time run on it into a fiction.
3. Knowledge
4. Calibrated bicycle course measurement
5. Connections
6. The marathon distance (42.195 km / 26 miles 385 yards)
7. New York is remeasured and two world bests are voided
8. Evidence
9. Road courses are measured by the calibrated bicycle method with a Jones counter along the shortest possible route, with a short course prevention factor of 1/1000 applied to the calibration constant. V55 verification basis: the PDF was identified and summarised through search; direct retrieval was blocked by the egress proxy and the manual was not read in full.