Calculating The Time Cut



There’s a time cut for every stage of the Tour de France. A rider finishing outside of the time limit is out of the race. Another of the Tour de France’s Frequently Asked Questions is how are the time cuts calculated. Here’s the explainer and the numbers for this year’s Tour.

Why?

The time cut ensures no rider can coast around the course all day long, taking it easy when they’re supposed to race. It ensures a homogeneous peloton of riders making similar efforts each day.

Moving target

The time cut varies and is based on a percentage of the winner’s time on the day. But it’s more complicated than that because the percentage varies according to the type of stage and then the speed on the day. The idea behind this is to have a small amount of time for a short and flat stage, and a larger amount for a big day in the mountains.

Do the maths

First you have to check the “coefficient” of the stage. These are awarded to different stages to reflect their difficulty. Here is the table.

Once you have worked out the stage you need to know the winner’s time. You can of course wait for the winner to cross the line but you can also work out their average speed so far during the stage and forecast a probable arrival time. Once you have the winner’s time, real or forecast, you then calculate their average speed for the day because you know the stage distance, ie the distance divided by the winning time.

Once you have this number and the coefficient then it’s time to use one of the tables below to work out what the percentage limit is.

Let’s imagine today’s stage from Grenoble to Risoul, Stage 14 which is a Coefficient 4. If the winner does the course in 5h08m then this works out at 34.5km/h. So the time cut is 12% of this. 5h08m is 308 minutes and 12% of this is 36m56s. So the time cut is 5h08m + 36m56s = 5h44m52s.

If anyone knows of a website tool where I could embed a function on here to calculate this it’d be a useful tool sometimes.

Any rider outside the time cut is eliminated. Here is a snippet from yesterday’s post-race bulletin:

Dossard 25 is Rider 25, aka Alexander Porsev of the Katusha team and he’s out of the Tour de France because he finished 34 seconds after the cut.

@inrng Here he is half-way up Chamrousse. As always – he got the biggest cheers of the day 🙂 @letour #voiturebalai pic.twitter.com/O09avTdgBk — Mike de Garry (@Paparrazifull) July 18, 2014

There are two exceptions to the rule or rather the rule includes two exceptions. Here’s the wording:

Finishing times may be adapted under exceptional situations and unforeseen acts of God (weather conditions, blocked roads, serious accident or incident, etc.) according to the assessment of the Stewards’ Committee, with the agreement of the race management. If the percentage of eliminated riders rises above 20% of starters in the stage, permitted finishing times may be increased upon the decision of the Stewards’ Committee, with the agreement of the race management. It is understood that the riders who finish within the new permitted times will qualify for following stages, without a precedent being set for the rest of the race.

Tiago Machado crashed on Stage 10 and finished outside the time limit along with team mate Andreas Schillinger. But he was in ambulance for 12 minutes after the crash and the commissaires decided to deduct this time and therefore he and Schillinger made the time cut, that’s an example of the “serious accident” component. It could also include a level crossing or some other event that blocks or slows the rider.

The second point is the safety in numbers element where the gruppetto might contain 20% of the field. The idea is that the race cannot afford to see the peloton reduced by a mountain stage. But this is subjective and only applied in rare cases and when it happens riders are docked points from the points competition, a real penalty for any sprinters who miss the time cut as if they’re allowed in the race their chances of taking the green jersey can vanish.

Summary

Hopefully this explains the time cut and how it’s calculated. If you’re inclined you can create a spreadsheet where you have fields for the distance, winning time, stage coefficient and so on. Better still try doing the maths in your head. If you find it hard, spare a thought for the riders at the back of the race today who are doing the calculation several times a day all. Who said maths was easy?