The first thing to realize about the Tour de France is that it's about more than just guys going really fast on bikes. Also, it's more than just one race: there are races within races and other competitions unfolding nearly every day for the three weeks or so 200+ cyclists on 20+ teams wind their way through France 170-220 kilometers at a time. In any case, the Tour de France is not a solo sport. Cyclists like Lance Armstrong would not be able to do what they do were it not for the support of their teams.
The race itself:
The Tour de France is what is known as a stage race. That means that the whole race takes place over several days, with each day being its own race, or "stage." The winner of the race is the person who has ridden every day with the lowest cumulative time. It is possible for someone to win the entire Tour de France without ever having won a day's stage, just as it is possible for someone to win several stages but not the overall race. (More on the stages themselves and why that is later.)
The Tour de France itself is just that: a tour of France. Most of the stages bring the riders through the various parts of the French countryside, routinely finishing on the last day with an arrival in Paris and several laps up and down the Champs Elysees. In recent years the Tour has also gone into neighboring countries, and in one instance even included several days in Ireland. Much of France is flat, but the race usually spends several days in both the Pyrenees and the Alps, which offers several mountain stages and their race-altering dynamics. (See more on that later when the stages are discussed.) The race is run every day but two over about three weeks.
What riders can win:
Every day a rider can win a stage. Such a victory carries with it tremendous prestige, as well as a cash prize. A rider can also win the entire Tour if he has the lowest cumulative time at the end of it. Every day the race leader - meaning the person who as of that day has the lowest cumulative time - wears the "yellow jersey" (or "maillot jaune" as it's known in French). Armstrong doesn't care if he wears the yellow jersey every day - in fact, he would prefer not to (more on that later when strategy is discussed) - but he wants to be the one wearing it at the very end. (And actually, maybe a little earlier. But more on that later as well.)
(Incidentally, other stage races also use colored jersey to denote race leaders. The Tour of Italy, for instance, awards a pink jersey in honor of the color of the paper the sports newspaper sponsoring the race publishes on.)
Meanwhile, there are a few other significant jerseys that can be won and worn as the race goes on. The green jersey, for instance, is worn by the leader in the sprint points competition. At various points along the race route in any given stage there are spots where the first person to pass them gets a certain number of points. So even on a very long, flat 100+ mile stage there will be mini-races at these various junctures as the sprinters in the race jockey to pick up the available points. Whoever has the most points cumulatively gets to wear the green jersey in the next day's stage, but what they all want is to be awarded it at the very end of the entire Tour.
Similarly, there is also the polka-dot jersey (it's white with red polka-dots). This jersey is for the "king of the mountains." Like with sprints on the flat parts, there are points awarded to the first people to cross the mountain peaks. Whoever has the most points in this category at the very end of the race wins the jersey (just as whoever has the most cumulatively along the way gets to wear it during that next day's stage).
Not everyone in the race is out to win the yellow jersey at the end. There are some riders who come to the Tour only to win the green or polka-dot jerseys. Arguably they could win one of those jerseys and also be the race leader (in which case the lesser jersey gets awarded to the runner-up), and some courses some years cause such a scenario to happen during the race (for instance, Armstrong has sometimes been, particularly near the beginning of the race, the leader in both the green and yellow jerseys - in those instances he's worn the yellow), but for the most part that won't happen by the end of the race given the effort and strategy involved to win any of these jerseys.
(There's also the white jersey, worn by the best young rider, but though there's prestige for whomever wears it, it's not as sought after or coveted as the other jerseys, partly since only a small portion of the peloton is eligible for it. The race establishes an age cutoff, and the rider with the lowest cumulative time who's also younger than the cutoff gets the jersey.)
There are generally three types of stages, although within each type there are certain variations. The main types are time trials, flat stages, and mountain stages. Time trials (called "contre le montre" or "CLM" in French and on the Tour de France website) are distinctive because the racers ride one at a time against the clock. Normally all riders ride together in a giant pack known as a "peloton," where teammates are available to support each other and the other dynamics of riding with 150+ people affect the outcome of the stage. But with time trials the riders are on their own. Except when it's a team time trial. In a team time trial the entire team rides together and the first five riders are awarded with the time of the fifth rider to cross the finish line. Actually, if other riders finish at about the same time they get the same time too, but what's significant is that it requires the entire team to work together. So even if Armstrong could go out and ride faster than the rest of his team it would be pointless, because he'd still only get the time of the fifth rider. So it's in his interest to support his team and help them finish collectively fast. (See the discussion on drafting below for more on that.)
It's also worth noting that time trials can be either flat or mountainous, which can affect which riders will do well in it, and to mention the Prologue. The Prologue happens on the first day of the Tour de France. It's a time trial in that each rider races the clock. But it's short. Most time trials are about 35-50 kilometers, whereas the prologue is often less than 20. This means that someone who might win a regular time trial might not also win the prologue, or vice versa, although in recent years there's been a significant overlap.
Of the regular stages, when everyone races all at once, most are long and at least mostly flat (although there are some stages that seem flat but actually have enough low rolling hills in them to affect the race that day). On these days the peloton tends to stay close together so that teams can help their leaders conserve their energy, but at the very end and at the junctions where the sprint bonuses are awarded the contenders for the green jersey and their teammates tend to jockey heavily for position. These sprints, though exciting, can also be dangerous. Lots of closely cramped, uber-competitive riders make crashes a frequent occurrence, particularly on days when the weather is wet. And when one rider goes down, he often takes other riders with him as there's very little that crammed-together, speeding riders can do to avoid the fallen. Sometimes there are serious injuries as a result, with racers often being forced to drop out of the race. (Tyler Hamilton made history when, even after sustaining a broken collarbone in one of these crashes early on, he not only finished the entire race but later won a stage.)
When the entire peloton crosses the finish line in a bunch, every rider in that bunch gets awarded the same time. This is why Armstrong doesn't care so much if he finishes 143rd, because as long as there's no gap between person who finishes first and the group of people Armstrong's in, he'll still get the leader's time. Or very nearly: the winner (actually, the first three placers) of a stage gets a time "bonus," or deduction, from his cumulative time.
And then there are mountain stages. Mountain stages are grueling stages where the riders traverse hill after hill (usually), sometimes ending the race on an uphill climb. Mountains are ranked 1-4 based on their grade, with 1 being the most steep. There are also "HC" hills, meaning "hors category" (above categorization) and too steep to rank. These are found in the Alps and Pyrenees. Stages with a lot of 2-4 climbs are interesting, but not usually very pivotal to the race. Stages with a lot of 1 or HC climbs, especially when they end on an uphill, do tend to be very pivotal as only certain riders can really do well at them. Sprinters, for instance, tend to do dreadfully, and historically many of them have quit the race after winning some of the early long flat stages and before the Tour has arrived in the mountainous regions. In a mountain stage the people who are good climbers can often vastly improve their position in the overall race. As the non-climbers limp over the hilltops, the climbers (and their teams) can set the place and put minutes between them and their competition. (In the strategy section this will be explained more thoroughly.)
No rider goes to the race alone. He always starts out as one of nine people. Often that number drops, as people drop out of the race due to accidents - or, as in the case of some sprinters - by design. But the people with the best chance to win a jersey are usually those with the most and strongest teammates who are able to hang on the longest. Because no one can win a jersey alone.
Teammates serve a few functions that help the lead riders be competitive. For one, they can serve the leaders on a practical level. Races are long and riders need fresh food and water along the way. These are generally provided by the team cars that follow the pelotons. But it would slow the riders down too much and ruin their pacing if they had to constantly go back to the cars for refueling, so the leaders have their "domestiques," or supporting teammates, shuttle back and forth between the cars and the lead riders to get them what they need.
Teammates can also provide a lot of protection to their leaders. They can help position the rider at a good spot in the peloton, and strong teams can set the peloton's pace. They are also available to provide drafting to their leader so he can conserve his energy better. Even on the final climb of a long, mountainous stage, the rider with the most teammates left to support him will be in the best position to contend on that stage.
A note about drafting:
Except for individual time trials, drafting is a huge component of the Tour de France. Drafting involves having one rider do the extra work of absorbing wind resistance, and others following in his shadow. Vast amounts of energy can be saved by drafting (following) another rider, and these energy savings can significantly affect the outcome of both individual stages and the entire Tour as riders strategize when and how to burn their energy.
A rider who wants to win the green jersey will have teammates who know how, at the critical points, to "lead out" the sprinter. The sprinter will draft his teammate up until the last minute, and then take off in an all-out sprint to cross the lines before his competitors. The strategy demonstrated here depends on team construction - meaning what kinds of talents the riders on the team have - and, within the race, the positioning the team can give the lead rider. For example, it would be no good for a green jersey contender to end up lost in the middle of the peloton and not be able to get to the front to contend for the sprints. A strong team will make sure the contender is placed near the front at the critical times.
Polka-dot jersey contenders also use their teammates to help them draft and save their energy, although in some mountain stages you may see polka-dot jersey contenders do something that a yellow jersey contender will usually not: go out on their own. On a stage when there are many hills, each of them offering mountain points, you will sometimes see riders break away from the peloton and become several minutes ahead, just so that they can pick up all the mountain points on their own. The problem with this strategy, however, is that it burns a lot of energy and often they flame out before the end of the stage and finish near the back of the pack. It also saps a lot of energy that riders need to last the whole Tour, and that's why yellow jersey contenders rarely do this. On the other hand, for those who can do it, (e.g., Richard Virenque) it's a good strategy for picking up enough points during the course of the stages to win the polka-dot jersey.
In any stage, at various points riders try to "attack the peloton" and go out on their own. The peloton then collectively decides whether to chase down that rider, or let him try to get away. Often riders can pick up several minutes on the peloton when they attack, but because they get tired and the peloton is so efficient in knocking down wind resistance, the peloton usually catches up near the end. But not always, and it's sometimes a gamble that the peloton makes to let riders go and not chase them down right away. Normally the teams have some idea of which riders will be a threat to the overall "GC" (or "General Classification," the ranking of riders by their cumulative times) and the peloton might be more willing to let someone who is not a good climber, for instance, take a big lead since the climbers/yellow jersey contenders know they will be able to pick up the time lost to him when they hit the hills. However, every so often the peloton seems to miscalculate, and someone who otherwise would not be favored to win the Tour picks up enough time on a long flat stretch to become a serious contender in the overall GC.
For someone like Armstrong, his team's game plan is to control the peloton and be the people able to make these kinds of decisions. His team also likes to keep Armstrong in a good position and be able to set an advantageous pace. Position is important for two reasons: one, in case of accidents or bad conditions it's much safer for Armstrong to be up front. One year the Tour may have been decided when Armstrong was in front of a crash that one of his yellow jersey competitors was caught behind of. Armstrong finished that day several minutes faster than the other rider, and was able to keep that time advantage through the end of the Tour. (Since then, however, the rules have been changed so that if there's a crash within the last few kilometers of the finish line, riders caught behind it will be awarded with the same time as those in front.) The other reason position is important is because if one of Armstrong's competitors for the yellow jersey attacks and tries to put time between him and Armstrong, Armstrong needs to be in a good position to respond to the attack. If he's going to keep up, he'll have a hard time doing it from the back of the peloton. Meanwhile, pacing is important because Armstrong's team wants to make sure he saves his energy for the stages when he stands the best chance to get the greatest time advantage on his competitors.
One of the reasons that Armstrong is such a perennial winner is because he excels at two kinds of stages: time trials and mountain stages. Some years the Tour winners only had to be good at one or the other, but now it requires an ability to excel at both since these are the stages when it is most possible to pick up time ("go significantly faster") than their competitors. Mountain stages, particularly those ending on an uphill, are excellent times for an energetic Armstrong to beat his competitors by several minutes by out-climbing them on the last hill. Here also Armstrong's team helps make the difference, because if he has strong riders with him they can share the work (draft each other) to get up the hill.
There's one more item to note with regards to strategy, and it echoes some points raised in the section about the team: who is on the team. Armstrong's team is hired specifically to support Armstrong's quest to win the entire tour. This means there tends to be several good climbers to help him get up the hills, and riders who are also good time trialists to help him win the team time trial stage. Only on individual time trials do his teammates get a chance to shine solo. (Although even then they help him out by communicating to him the conditions they've encountered. Time trials are run in reverse order, with the current race leader going last. Normally this means Armstrong rides near the end, so all his teammates will have had a chance to see the course and can give him some idea of what to expect on it.)
Other teams, however, tend to have several leaders, or function more as an ensemble, where teammates take turns essentially helping different people achieve different things, like stage wins or jersey points. Often teams share prize money with all the racers, so it's in the supporting riders' interests to help meet the team's collective goals even if it may seem to be at the expense of their own.
As mentioned earlier, Armstrong does not want to wear the yellow jersey the whole race. He tends to get it early on, when the only time results are from the prologue where he usually does well. But he gladly gives it up in the coming days as the race flattens out into long stages. The yellow jersey wearer becomes a target with everyone trying to take it away, particularly in the beginning when time results are closer together and even the sprinters will take a shot for it. It is very draining to have to defend the yellow jersey, and Armstrong would rather not be bothered with that until much closer to the end.
c. 2005 Cathy Gellis