Can today’s cyclists be trusted or are they pedaling through deceit? A statistical analysis of cheating in the Tour de France's history

[#1]

As the summer approaches, so does the 111^th edition of the Tour de France, which begins on June 29 in Florence, Italy. For those who are not familiar with the Tour de France (aka the Tour), it began in 1903 and takes place annually in late June thru mid-July. The race is broken up into stages that are ridden daily throughout France and surrounding countries. The Tour is one of the most grueling athletic competitions, and the winners are some of the most celebrated and famous athletes on the planet. The quest for Tour de France glory has driven cyclists to transcend the boundaries of human potential. Transcending those boundaries has led some cyclists down the unscrupulous path of winning at any cost. This blog looks at past winners – both scrupulous and unscrupulous – to determine if today’s cyclists can be trusted.

In July 2023, the 110^th edition of the Tour de France finished with Danish rider Jonas Vingegaard winning the race, which began in Bilbao, Spain, and ended in Paris after 21 stages. The map of the race is shown below.

In winning the race, Vingegaard completed the 3,404-kilometer route in 82 hours, 5 minutes, and 42 seconds. He bested his closest rival, Tadej Pogacar from Slovenia, by 7 minutes and 29 seconds. My colleague and fellow cycling fan Peter Polito mentioned that the margin of victory was remarkably small, even though most commentary on the victory asserted it was a convincing blowout win by Vingegaard. To sum it up, Vingegaard won by 449 seconds after ridding over 82 hours, which translates to about ~0.15% margin of victory. In other competitions, this would be considered a photo finish; it is equivalent to winning the 100-meter dash by a little over a hundredth of a second. How does this compare to time gaps in past Tours?

This graph shows the time gaps between the winner and second-place rider throughout the years. The time gap in 2023 is the largest gap since 2014. In fact, the gap between first and second place has only been larger three times since 1984. In Tour de France terms, 2023 really was a blowout win for Vingegaard.

However, this result brought up a few questions about the performance:

1. Was this version of the Tour longer than usual, thus resulting in bigger time gaps?
2. How did Vingegaard’s speed over the course of the Tour compare to speeds in the past?
3. Should fans question the validity of this win with so much controversy in cycling history?

The first question is very easy to answer. In 2023, the race was 3,404 km, which is slightly longer than the 3,328 km of 2022 and 3,383 km of 2021; it was shorter than the 3,483-km race in 2020. While length might be playing a role, it does not appear to be the major driver. It did make me wonder about the history of the distances, as it appears the gap between first and second place finishes had been trending downward. If we look at the average distance for a Tour de France by decade, it is clear that these races have become shorter over the years.

Let’s look at the second question. Was Vingegaard faster than expected when looking at past results? The graph below shows the average speed of the Tour de France winner each year. The race was not timed from 1905 to 1912; rather, points were given based on finishing position (there is more on the reasoning for that below). There was no race during both World Wars. The doping era (1999-2006) is highlighted, when all the winners during that span were found to have doped so their wins were vacated. The Tour has had many more doping issues, which we will delve into later.

Looking at the graph, Vingegaard had the third-fastest average pace of a Tour winner throughout its history, only bested by himself last year and Lance Armstrong in 2005. We will look at this in a little more detail when we answer the last question.

There is a strong trend upward in speed throughout the years. There are plenty of reasons to believe that speeds have improved naturally: improved roads, improved bikes, shorter Tour distances, support vehicles, and sponsored teams that spend all year training for this event. If you look at the picture below from the 1927 Tour de France, you can see a lot has changed over the last hundred years of cycling.

Julien Vervaecke and Maurice Geldhof are smoking during the 1927 Tour de France. Gustaaf van Slembrouck is lightning the cigarette.

While there are many natural reasons for the increased Tour speeds, the race is also full of controversy and scandal, which means, unfortunately, every win faces extra scrutiny. If you are not familiar with the history of the Tour, the most infamous villain in the cycling world is Lance Armstrong. He won the Tour a record seven times in a row (1999-2005) before he was found guilty of doping and thus stripped of all those titles. Armstrong is not the only cyclist to use doping to gain an advantage. 2006 winner Floyd Landis and 2007 third-place finisher Levi Leipheimer were also found guilty and stripped of their titles, as well as a long list of riders that were caught with positive tests during the races. It is safe to say that the Tour in the late ’90s and early 2000s was heavily influenced by doping.

Doping in the Tour de France started long before the 1990s. Many doping scandals have plagued the Tour through the years, including wide use of alcohol, ether, amphetamines, opioids, steroids, human growth hormone (HGH), and erythropoietin (EPO). In fact, up until the 1966 Tour, it was not illegal to dope in the race and no testing was performed. Testing became mandatory after British rider Tom Simpson died during the 1967 Tour de France with vials of amphetamines found on his body https://en.wikipedia.org/wiki/Tom_Simpson. Even with the advent of testing and the death of a fellow rider, the doping continued, with many of the champions throughout the years being caught or linked to doping. It has been a constant struggle to police doping. Since 1966, nearly half of the Tour winners (25 of the 56 winners) admitted to doping or failed doping tests. https://en.wikipedia.org/wiki/Doping_at_the_Tour_de_France

There has been controversy in the Tour de France long before Lance Armstrong or the doping of champions in the 1960s. All the way back in 1904, all top four finishers and 12 of the 27 finishers were disqualified. The reasons for specific disqualifications were never made public, but allegations of illegal use of cars, trains, and spectator interference have been cited (https://www.rediff.com/sports/2004/jul/06tour.htm). The 1904 Tour was so bad that it led to a change in the rules, creating a point-based system instead of a timed event. This system lasted until the 1912 Tour. The modern-day Tour de France still has two competitions that harken back to the point-based system of those early Tours. The Sprint and King of the Mountain competitions (which award green and polka-dotted jerseys) are based on points awarded throughout the race.

Now let’s look at the last question. Should cycling fans be skeptical of Vingegaard’s 2023 win?

I have been following cycling for years, and it is very hard to give riders the benefit of the doubt. Looking at the winners’ speeds dating back to 1966 when testing for doping started, there is a clear trend. https://bikeraceinfo.com/tdf/tdfstats.html.

Since 1966, the average speed of Tour de France winners has increased ~0.12 km/hr each year. The average winning speed today is ~6.8km/hr faster than in 1966. Seeing faster speeds each year is an expected trend. In this graph, the champions who have been caught doping are represented with a red plus sign. If we look at Vingegaard’s speed over the last two years, it doesn’t seem to raise any suspicion. His 2022 ride and 2023 ride are both close to the trend line of improved speed throughout the years. If we look at the trends of the known dopers vs. the clean riders, the story is a little different. The 2023 ride for Vingegaard seems to be well-aligned with clean riders of the past. The 2022 ride is much closer to the known doping riders trend line.

This is not to say that Vingegaard was doping in 2022 and not doping in 2023. It seems like a very unlikely scenario that a rider would dope to win one year, decide not to dope the following year, and then win again. It appears that Vingegaard is not doping to win the race and is one of the greatest cyclists of all time.

It appears that the 2023 Tour de France was a dominant win for Vingegaard, who had the third-greatest margin of victory since 1984. In winning the Tour, Vingegaard had an average speed of 41.4 km/hr, which translates to the third-fastest Tour of all time. Despite the history of doping in the Tour and the fast pace of Vingegaard, the 2023 Tour seems to be a believable win for a clean rider. As a jaded cycling fan, it wouldn’t surprise me if the recent Tour de France cyclists followed the long tradition of cheating to win the race, but for now it does not appear that is the case. Looking forward to this year’s race!