Sport and timing
Tour de France: how the world’s most famous cycling race is timed
· 5 min read
In short
- Bicycles carry transponders with unique signals, detected by sensors at intermediate timing points and the finish. A decoder sends the data to the timing control centre known as Chronopole.
- A photo-finish camera at the finish captures up to 10,000 images per second and distinguishes differences with millimetre precision. In 2017, it separated the first two riders on stage seven by 3 ten-thousandths of a second.
- Times are added together across the stages, and the lowest overall time determines who wears the yellow jersey. Tissot is the official timekeeper.
A cycling race is timed differently from a running race. Riders travel at high speed, often finish in groups and accumulate their stage times for the general classification. The Tour de France is therefore an excellent example of professional race timing in action.
Transponders and Chronopole
Each bicycle is fitted with a transponder carrying a unique signal, detected by sensors along the course. At the finish, an antenna connected to a decoder identifies the rider and sends the data to the timing control centre known as Chronopole. We explain a similar system used for cars in How Formula 1 timing works.
In a time trial, each rider starts individually and is timed from their own start; in a mass-start stage, time is measured from the official start. The riders’ times are then added together, and the lowest overall time determines who wears the yellow jersey. The official timekeeper is Tissot, part of the Swatch Group. You can read more about such partnerships in Official timekeepers: Omega, TAG Heuer and Tissot.
Photo finishes and sprints
In a sprint, the front wheel can decide the finishing order. The finish-line camera records the line up to 10,000 times per second and creates a continuous photo-finish image from which officials determine the order with millimetre precision. In 2017, such a system separated the first two riders on stage seven by 3 ten-thousandths of a second. Learn how the photo finish was developed and how it works in Photo finishes in horse racing.
The timing team and the time trial
The time trial is a special discipline: riders start individually at intervals and race against the clock. We cover individual starts and their rules in Types of start: mass, wave and individual.
Groups and equal times
When riders finish in one group without a significant gap, they receive the same time in the general classification even though their finishing positions differ. This avoids endless disputes over fractions of a second in a bunch finish.
What this means for amateur events
A cycling marathon or gravel event can be timed with an RFID chip attached to the bicycle or helmet. Be careful with metal: a chip stuck directly to the frame may not work, but a chip designed for use on metal will. See Race timing for cycling and MTB events for practical guidance.
Frequently asked questions
How is the Tour de France timed?
The bicycles carry transponders with unique signals. Sensors at intermediate timing points and the finish detect them, and a decoder sends the data to the Chronopole centre. A photocell starts the clock at the beginning of a stage, and times are added together across the stages.
Why is a photo finish used in cycling?
Riders in a sprint are often separated by fractions of a second. The finish-line camera records the line up to 10,000 times per second and determines the finishing order with millimetre precision.
Who times the Tour de France?
The official timekeeper is Tissot, a brand within the Swatch Group. The timing control centre is known as Chronopole.
How is the order decided when riders finish in a group?
Under the rules, riders who finish in the same group without a significant gap receive the same time. In a bunch finish, the finishing order is therefore determined by photo finish, but each rider receives the same time in the general classification.