Proposal 66: 3D.15.2 Distance Measurement for Fixed Distance Races [ Revision 3 ]

Committee: 3. Road Racing
Submitted on 2025-07-09
Status: Passed on August 10, 2025

Background

The current wording of Rule 3D.15.2 does not provide a sufficiently precise framework for the measurement of fixed-distance races, especially in the context of potential World Records. This limitation has been identified and discussed with the World Record Committee. To ensure that fixed-distance race results can qualify for record recognition, it is essential that the course be measured before the event using a method that guarantees both accuracy and consistency.

Ideally, an official measurement should be conducted in advance using a Jones Counter, following World Athletics procedures or a method of comparable precision. However, in situations where such a full official measurement is not feasible before the race, a simplified but conservative method can be used instead. This method does not allow for direct recognition of records, but it ensures that the course length is not underestimated.

The proposed simplified method maintains key elements of best practice: it includes the careful calibration of the Jones Counter on a straight, stable calibration course of 300 to 500 meters, measured with a certified steel tape of at least 30 meters. It eliminates lower-priority steps such as post-race recalibration or temperature correction, and instead requires both calibration and course measurement to be performed at a time of day when ambient temperature is stable. A correction factor of 1.003 is applied to the calibration factor to introduce a deliberate margin of safety, ensuring that the measured course is slightly longer than the advertised distance. This ensures credibility while maintaining practicality.

This dual approach—allowing both official and simplified pre-race measurements—ensures that fixed-distance races are measured with appropriate rigor, while also providing organizers with a workable alternative when official measurement is not logistically possible. Any potential World Record performances based on the simplified method must still be confirmed by an official measurement conducted after the event.

Proposal

Old rule :

3D.15.2 Distance Measurement for Fixed Distance Races
In the case of fixed distance races, the course must be accurately measured along the shortest possible path. The course must be guaranteed to be no shorter than the advertised distance.
The following procedure is acceptable for accuracy. A more accurate method is also allowed.

  1. Set out a calibration course on straight, flat asphalt, with a minimum length of 100 meters, using a steel measuring tape of 5 meters or longer.

  2. Ride the calibration course at least once with a bike or unicycle (minimum wheel size 24 inch). Ride normally, without too much wobble, and at normal speed. Take care that mounting and dismounting don't cause the wheel to swerve, or be lifted from the surface. Carefully count the number of wheel revolutions required to ride the calibration course. Include partial wheel revolutions (for example through counting the number of spokes passed for the last partial revolution).

  3. Calculate the wheel roll‑out (meters per revolution) from step 2.

  4. If you are going to use a cycle computer: enter the wheel roll‑out value to the nearest millimeter in a reliable cycle computer with a wheel sensor (such as a magnet).

  5. Fit the cycle computer, or a wheel revolution counter, to the same bike or unicycle used in Step 2.

  6. Ride the actual race course, following the shortest possible path. Take care to ride in the same way as in step 2.

  7. Read the distance from the cycle computer, or calculate from wheel revolutions and wheel roll‑out.

  8. Calculate the applicable safety margin by adding up (1) 0.4% of the measured distance, and (2) the resolution of the cycle computer distance readout. Example: if your cycle computer shows 10.15 km, the safety margin is 0.4% · 10.15 km + 0.01 km = 0.0506 km = 50.6 m. Note: you can skip (2) if you use a wheel revolution counter that can resolve single wheel revolutions.

  9. Add the safety margin to the actual course (for example shift the start and/or finish line), to guarantee that the course is at least the advertised distance.

    Note that Steps 2 through 7 must be done without breaks. The same rider should ride the calibration course and the race course. The tire pressure should not be altered in the meantime.

New rule :

3D.15.2 Distance Measurement for Fixed Distance Races

1. For fixed-distance races, the course must be measured accurately along a path 30 cm from the kerb or other solid boundaries to the riding surface, to ensure that the measured distance is at least equal to the advertised distance.
1.1. When ever possible an official measurement must be carried out before the race. For this the course distance must be measured using a Jones Counter, following the official IAAF recommendations or an equivalent method offering comparable accuracy. This measurement ensures the validity of the results and the potential recognition of records.
1.2. If an official measurement before the race is not feasible, a simplified method using a Jones Counter may be used. This method maintains a high level of accuracy and ensures a conservative measurement by applying a correction factor of 1.003. No records can be recognized by this measurement.
2. If the simplified method was used before the race, an official measurement must be conducted after the event to validate any potential record.

3D.15.2.1 Simplified method using a Jones Counter

1. The following equipment is required for measurements using a Jones Counter:
i A certified Jones Counter, mounted on a bicycle wheel (preferably with a smooth, well-inflated tire).
ii A calibration course: a straight, flat, and stable section of road with a known precise length, ideally between 300 m and 500 m.
iii A certified steel measuring tape of at least 30 meters, used to confirm or verify the exact length of the calibration course.
iv Markers to clearly define the start and end points of the calibration course.
v A notebook or app to record all measurements.
2. The simplified method using a Jones Counter consists of three steps, according to i - iii. Calibration and course measurement must be carried out consecutively at a time of day when there is no great variation in temperature.
i Calibration of the Jones Counter: a critical step
Calibrating the Jones Counter is essential to ensure the accuracy of all subsequent measurements. This step must be performed meticulously:
i.i Setting up the calibration course: Choose a straight, stable section of road, and confirm its exact length using a steel measuring tape. Ensure that the start and end points are clearly marked and fixed.
i.ii Measuring the calibration course: Perform 4 measurements (2 round trips) of the calibration course with the Jones Counter:
Ride slowly and steadily along the full length of the course, maintaining a straight line.
Record the Jones Counter readings at each end for every pass.
i.iii Managing errors: If any reading deviates significantly from the others, it must be discarded. Such errors may arise from deviations in the bicycle’s path or instability. If necessary, repeat the 4 measurements to obtain reliable data.
i.iv Calculating the calibration factor (CF):
Average the valid readings to determine the calibration factor:
CF = Average number of Jones Counter counts over 4 measurements / Length of the calibration course in meters
i.v Applying the correction factor: Apply a correction factor of 1.003 to ensure a conservative measurement: 
CFcorrected = CF × 1.003
ii Measuring the course:
ii.i Starting point: Position the bicycle equipped with the Jones Counter at the starting point of the course.
ii.ii Measurement: Ride slowly and steadily along the shortest possible path of the course (the "ideal line").
ii.iii Final reading: Record the Jones Counter reading at the finish point.
iii Calculating the measured distance:
Use the corrected calibration factor to convert the Jones Counter readings into the actual distance:
Actual distance (m)= Total number of Jones Counter counts over the course / CFcorrected

Body

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References

Discussion

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Change Log:

Revision 3 changed by Simon JAN (09 Jul 07:59)

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Revision 2 changed by Simon JAN (09 Jul 07:57)

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Revision 1 changed by Simon JAN (09 Jul 07:54)

Votes on this proposal:

10 out of 14 voting members have voted.

Agree: 8, Disagree: 0, Abstain: 2.

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