Tour de France Blog Series: Part 3

Hello and welcome to part 3 of my Tour de France blog series. If you haven't done so yet, please take a look at part 1 and part 2 - otherwise this entry might be a little confusing. This entry will highlight some basic concepts in cycling tactics, which are applicable in cycling group races of all levels.

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Drafting and Attacking

What sets cycling apart tactically from some other racing sports such as running is the concept of drafting. While riding a well-tuned bike on flat ground, the most significant source of energy (i.e. speed) loss is air resistance. This is unlike running, where much of the energy a runner exerts is ultimately absorbed by the ground, meaning a runner cannot "coast" the same way a cyclist can. When an object such as a cyclist moves forward, it moves air out of the way. Thus, the area immediately behind the cyclist - called a slipstream - has less air, and thus less air resistance. A cyclist will often draft behind another cyclist by riding very closely behind another cyclist.

On flat ground, a cyclist can use 40% less energy by drafting, and it is relatively easy to chase anyone while riding in their slipstream. Because of this, a cyclist who wants to get a lead on another cyclist can only do so with a quick burst of acceleration - called an attack - such that by the time he reacts, the opposing cyclist will be too far behind to take advantage of the slipstream. Ultimately, in a group race, acceleration is more important than speed. This concept becomes extremely important in group races, where riders begin racing all together and can ride as a pack. Conversely, it also explains why good time-trialling (where drafting is not allowed) is a different skill from good group racing; in time trials, it is speed and aerodynamics that are key.

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The Peloton

Now that we've learned what happens when one cyclist rides behind another, let's get into what happens when you have not just two but many dozens of cyclists. A peloton is essentially many cyclists riding in a bunch. When the peloton is in formation, riders at the very front are "doing the work" while all the others draft behind. Typically, riders will take turns doing the work, then "peel off" to put someone else in front. Therefore, it follows logically that, on average, riders in a larger peloton will use less effort than riders in a smaller peloton. Similarly, a larger peloton can more easily move faster and chase down a smaller group ahead.

Now here is where team-related tactics come into play. Because the riders in front control the pace of the peloton, a team or a group of teams can push to the front of the pack and increase or decrease the speed of the peloton depending on their strategy (more to come on when and why a team would increase or decrease pace). On the other hand, a team with no concern about the peloton's speed can choose to conserve energy by never coming to the front.

Riding near the front of the peloton is important for team leaders. The most obvious reason is that if the peloton splits up, the contenders don't want to be stuck in the back and lose time (recall that all riders in the same peloton receive the same time at the end of the stage). Additionally, if a crash occurs, riders near the front will be in less danger, as they will have fewer fallen riders to avoid. For these reasons, the back of the peloton will often be populated with domestiques.

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Breakaways: Attacking the Peloton

As we will learn later in more detail, if the peloton sticks together on a flat stage, the race will favor sprinters who will conserve as much energy as possible and go all out in the last few hundred meters.  Thus, all those non-sprinters who want a shot at winning a flat stage must eventually become part of a breakaway.  A breakaway occurs when one or more cyclists launch an attack on the rest of the peloton, forming a smaller group of their own ahead of the main peloton.  The riders on a breakaway, while ultimately competing against each other, must cooperate by sharing turns doing the work and not resorting to so-called "cat and mouse" tactics.  Occasionally, a cyclist will practice "wheel sucking" by constantly drafting and never moving to the front to do the work, then using all his conserved energy to steal the stage victory with a sprint at the finish.  Not only is this practice selfish and frowned upon - it also increases the chances that the breakaway will fail.  However, one in a breakaway might "wheel suck" in an acceptable fashion if he has no interest in the breakaway's success.

The dynamics of a breakaway are different in a stage race like the Tour de France as opposed to a single-day race, and this is because the objective of a single-day race is to finish in first, while in a stage race, there are different classifications to compete in, and furthermore cyclists must budget their energy over many days.  In a single-day race, whenever an attack happens, riders must decide whether the attackers are threats to win, or whether they will tire out and get caught.  This judgment will determine whether they should join the breakaway or stay with the peloton.  Eventually, multiple splits in the peloton will occur until a winner is crowned.  In a stage race, conserving energy is important, so teams aiming for more than just individual stage victories will usually adopt strategies that will give them the most returns for the least effort.  These strategies will be explained more in parts 4 and 5 of this blog series.

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Ascents and Descents

Drafting is most important on flat ground, where it saves a cyclist the most energy.  However, while going uphill, the main factor slowing the cyclist down changes from air resistance to gravity.  Thus, the effects of drafting are greatly diminished on a climb, and accordingly, the peloton will usually crumble on the tall mountains.  However, if possible, cyclists will often tend to ride in a pack anyway to make pacing and reacting to opponent's moves easier.  While the heavier riders fall behind, the GC contenders will usually form a lead peloton where they will make repeated attacks on each other to try to cause rivals to fall behind.

On descents, the bike will naturally accelerate even if the cyclist does not exert any energy, so drafting does not really give any additional advantages.  However, cyclists will often form a paceline to minimize the risk of crashing.  While the peloton will tend to split on climbs, it will tend to reform on the descents that follow.  Riders can catch up to those ahead of them if they dare do so by adopting a more aerodynamic position.  On descents, gaining ground becomes less related to energy output and more to aerodynamics and technique.  Therefore, even poor climbers can sometimes catch up to the group on a descent.  Additionally, on the flat ground at the bottom of a descent, attacking riders will then again be at a disadvantage compared to the peloton.  These are the reasons the GC contenders will almost always make their biggest moves on stages with mountaintop finishes, or stages that end on descents - so as to maximize time gaps.

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In part 4, we'll learn about all the different types of stages found in the Tour, and the strategies that are typically used for each type of stage.  Then in part 5, we'll wrap up this primer with some insight on long-term strategies that teams adopt in order to produce a winner.  Until then, thank you for reading!