"Fast" or "slow" isn't the only determining factor -- although in the end that's what matters most. Physical talents allow some riders to specialize in sprinting, others to climb better than average, still others to time-trial, and a lucky few put all the disciplines together and compete for the general classification.
A is for Armstrong, the overall favorite, and Z is for Zabel, the sprinter extraordinaire. They are the brightest stars in this year's Tour, but there are plenty of opportunities for specialists to shine.
What makes each specialist so good at their game?
CLIMBERS
In several of this year's Tour stages, riders will tackle four or five monster climbs per day. Pick out the steepest hill in any city, stretch them out anywhere from a couple to a dozen blocks, and that's an idea of what some of the climbs in the Tour are like.
What allows a climber -- or for that matter, any of the riders -- to manage the endless climbs? In short, aerobic capacity and strength-to-weight ratio are the key components to climbing.
VO2 max is what determines aerobic capacity -- your ability to produce energy aerobically. The higher the number, the farther and faster a racer can push. Regular exercise trains your system to transport more oxygen-rich blood to your organs and muscles, but in truth there is a big limiting factor that no one can control -- genetic makeup.
Tour riders all have high VO2 max levels, averaging in the mid-70s (the unit of measurement is ml/min/kg), making them all genetic freaks, to a degree.
For comparison's sake, Lance Armstrong has a VO2 max of 83.8; at one point Greg LeMond was recorded at an astonishing 92. Miguel Indurain is said to have had an 85. The highest recording is supposedly 94, attributed to Nordic skier Bjorn Dahlie. (Humans pale in comparison to many animal athletes, however: A thoroughbred horse's VO2 max is 150!)
Power-to-weight ratio, on the other hand, is something a rider can control. The strength needed to climb a mountain is countered by body weight (measured in terms of pounds of body weight per inch of height), so the lighter and stronger a rider, the faster they will go uphill. In a sport where every ounce counts, top climbers are as picky about what they eat as supermodels are.
A good climber doesn't necessarily have to be tiny, but typically a smaller rider can increase their power-to-weight output ratio more than a bigger rider. How did Armstrong, one of the best climbers in the sport, become such a force? The big reason is that he now weighs 30 pounds less than when he started racing.
Also, good climbers don't waste energy with extraneous rocking of the bike, or flailing of the head, elbows, hips or knees. Every movement has a singular purpose -- powering the cranks uphill.
Other gifted climbers to watch include five-time polka-dot jersey winner Richard Virenque (Domo-Farm Frites), resuscitating his career after a drug suspension; Jonathan Vaughters (Credit-Agricole), past winner atop Mont Ventoux; Armstrong's climbing lieutenant Roberto Heras (USPS), recent victor at the Tour of Catalunya, and Oscar Sevilla (Kelme-Costa Blanca), winner of the best young rider's jersey last year, and second in the 2001 Vuelta Espana.
The enigma is Laurent Jalabert (CSC-Tiscali), who won the polka-dot jersey last year based on a long breakaway in the mountains, but who also won the green sprinter's jersey in 1995.
SPRINTERS
While the climbers wage a slow war of attrition in the mountains, waiting to see who falls off the pace, the final sprint is like watching an action video game erupt.
The sprinters live for the first week of the Tour because the pancake-flat days before the first mountain stage are their best hope for a win. Fast-twitch muscle power is the name of the game, and big quadriceps power will be clearly visible in the first week.
Fast-twitch muscles are attuned to short, hard bursts of energy such as sprinting; slow-twitch are generally better suited for long, steady efforts (like hill climbing). Although genetics again play a role in what type of muscle tissue you are gifted with, sprinters focus on their specialty by training specifically to go hard and fast over short periods of time.
Apart from physical skills, sprinting requires razor-sharp nerves and reflexes to deal with breakneck speeds and abrupt direction changes at 40 mph near the finish. Most sprinters probably would admit to being a bit of a daredevil.
Nowhere in cycling is teamwork more evident than in a sprint finish. Few sprinters can take a bunch sprint without an efficient leadout train of teammates. The train relies on perfect timing to deliver the team's top sprinter into perfect position 200 meters from the line. Erik Zabel's leadout man, Gian Matteo Fagnini, is among the best in the business at this, a big reason Zabel wins so often.
While Armstrong must win two more yellow jerseys to match the best, Zabel is looking at winning his seventh consecutive green jersey this year; he is in a sprinting class by himself. Watch for Stuart O'Grady (Credit-Agricole), who had a chance to win the green last year on the final day, and three-time Belgian champion Tom Steels (Mapei), also a fixture at the sprint finish line.
American Fred Rodriguez (Domo) is a good sprinter -- perhaps not in the class of Zabel and company -- but good enough to win over a big breakaway group.
Borrowing a page from the climbers, Rodriguez credits keeping his weight down to allow him to make it over the climbs and to the sprint with enough energy to win.
"It's a fine point: Do you want to be faster, but suffer a lot more? In higher-level racing you can't be suffering too much or you're not gonna have a sprint anyways."
One of cycling's best sprinters, Mario Cipollini (Acqua e Sapone), a 12-stages winner at the Tour, won't be around this year. His team wasn't invited.
TIME TRIAL
They don't call it the "race of truth" for nothing. The individual time trial takes a rider out of his element and pits him against the clock instead of another person. This makes more of a difference than many would believe.
The physical traits of a good time-trial rider combine, to a degree, the skills of climbers and sprinters. A high VO2 max allows a rider to push harder and longer; but a heavier rider can also rely on sheer muscle force.
On some time-trial courses, such as shorter prologues, technical skills, such as cornering and accelerating over uneven ground, and smooth cadence come into play more than in other stages.
But a key ingredient to a great time-trial rider is the ability to focus completely. Finding the proper "zone" and staying in it, staying focused on producing the fastest possible ride for the hour or so a TT takes is of utmost importance in a race that can be decided by seconds. Armstrong has become such a good time-trial rider because he combines all three attributes to a T.
Other good time-trial riders include Tyler Hamilton (CSC-Tiscali), winner of a TT in the Giro; David Millar (Cofidis), Tour prologue winner in 2000; Christophe Moreau (Credit Agricole), fourth overall in 2000 and the winner of last year's prologue; Viatcheslav Ekimov, 2000 Olympic gold medallist and late addition to USPS -- specifically because he is such a good time-trial rider; and Abraham Olano (O.N.C.E.-Eroski), former world champion at the TT, who proved that even though you can TT, if you can't climb well enough to stay with the leaders you can't be a GC contender.
GENERAL CLASSIFICATION (GC)
Armstrong has been unbeatable for three years -- why? Apart from his obvious physical skills, one reason is that he has enough years of top-level cycling in his legs to withstand a three-week-long race. Younger riders rarely can perform at such a high level for so long. Another is that he relies heavily on his team -- behind sprinting, the next most important aspect of teamwork in the Tour.
Without "lieutenants" to deliver food and water, shelter them from the wind and chase down breakaway attempts, GC riders would be burned out by the time they reached a key stage, unable to perform at their best. Hierarchy does matter for best performances.
Among those who will attempt to dethrone Armstrong are Joseba Beloki (ONCE-Eroski), Igor Gonzalez de Galdeano (ONCE-Eroski) and Santiago Botero (Kelme-Costa Blanca).
And then there is an intangible skill that fuels the drive to win.
At the victory line in Paris after his first Tour win, Lance Armstrong was quoted saying: "If there's one thing I say to those who use me as their example, it's that if you ever get a second chance in life, you've got to go all the way."
It's kind of unfair to compare everyone else to Armstrong when he has that kind of motivation working for him. That motivation extends to his training, which allows him to excel in the Tour -- or any race he chooses to win.
ONCE's star Beloki bestowed possibly the highest honor on Armstrong that recent cycling history allows:
"Someday the domination of Armstrong must finish -- and on that day, I would like to be his successor. It would be great to say that I ended the reign of Armstrong, just like Riis ended the reign of Indurain."