21 stages – 3,430 kilometers - that's the challenge facing the riders at the 2011 Tour de France. No wonder it's also called the Tour of Pain! And this year, as a way of honoring 100 years of climbing the giant Col du Galibier - the participants will go up not once, but twice - with the end of the 18th stage being the highest finish in the Tour's history.

Alberto Contador and Andy Schleck are expected to be the front runners for the overall leader's maillot jeune.

Contador is one of only five riders in history to have won all three of the sport's Grand Tours, and as the world's best climber, will certainly be relishing the third and final week.

But having just won the Giro d'Italia, on a course which was arguably the toughest ever, and with a doping case hanging over him, which he denies, there are questions about the Spaniard's mindset.

I was horrified to hear that he was booed at Thursday's team presentation. As cycling commentator Paul Sherwen told me on ‘World Sport,’ shouldn’t he be presumed innocent? If he is, and I believe he is, what a terrible experience to have? Let’s hope he has a thick-skin!

Andy Schleck will take confidence from the fact that no one has been able to win the Giro and the Tour de France in the same year since the late Marco Pantani did it in 1998.

The Leopard-Trek rider finished just 39 seconds behind winner Contador last year and was the only man able to match the Spaniard in the mountains. A strong team which includes his brother Frank just might give him the boost he needs to win his first Tour at the age of 26.

Team Sky is putting their faith in 31-year-old Bradley Wiggins, who is determined to make up for a disappointing Tour last year. He finished fourth in 2009 and won the prestigious Dauphine Libere warm-up this time around which points to a possible podium finish.

Only the finest athletes can win the Tour de France. It's a grueling three week journey, much more than just a test of endurance, and only the strong will survive.

News of Alberto Contador’s positive test for Clenbuterol may have been a shocker to those of us outside the cycling fraternity, but I get the impression that it was an accident waiting to happen for those in the know.

Contador may have been portrayed as the poster boy for the new era of cycling, in which rigid testing would weed out all the cheats and eventually make doping scandals a thing of the past. But it always looked a bit like clutching at straws when your poster boy is a previous doping suspect – Contador lost his place in the 2006 Tour de France in connection with the Operacion Puerto scandal, before facing further insinuations of doping a year later, and again in 2009.

The Spaniard, while always found to be clean, was therefore a sitting target in some respects, since this seems to be a sport in which if mud doesn’t stick first time, you just keep on throwing it until it does. Just ask Lance Armstrong, who’s now under the scrutiny of a federal grand jury in the United States amid yet more allegations of doping during his career.

That said, Contador should be considered innocent until proven guilty. And by the way in which the International Cycling Union is downplaying the level of Clenbuterol in his system on July 21st, it seems highly likely that he will be exonerated of intentional wrongdoing.

If he is, then perhaps cycling needs to ask itself a serious question. How much transparency is too much transparency? If indeed Contador did ingest a miniscule amount of the banned drug via contaminated food, and if indeed he did so unwittingly with no intention of cheating, then why trumpet his faux pas to the whole world?

I can’t for the life of me believe that the intention of the World Anti-Doping Agency is to humiliate and undermine those who make a genuine mistake.

Surely anti-doping policies are designed to catch those who systematically and deliberately seek to enhance their performance by the use of banned drugs. If so, where is the sense in subjecting an athlete to a public pillorying for what is not the cliched cover-all excuse of an “error of judgment” but genuine bad luck. Furthermore, what’s the point in embarrassing the whole sport over a relatively trivial offence?

Of course, every sport needs to be clean and wants to be seen to be clean, and cycling is obviously showing a great desire to get its house in order. However, I think in an effort to be transparent you can sometimes become over zealous, and that’s a danger. After all, while it’s sometime necessary to air your dirty laundry in public, at other times it’s better to just stick it in the tumble drier and be done with it.

(CNN) – Arcane ideals of sportsmanship often seem out of time in a modern world of professional sport in which doping, match-fixing, handballs and controversies over referees, umpires and technology long ago clouded the Corinthian spirit to which purists still cling.

Given that cycling has long been tarnished by allegations over doping - arguably the most cynical and premeditated way in which a competitor can seek to gain an advantage over a rival - casual followers of the sport might have assumed that a sense of fair play had gone the way of the penny farthing.

This after all, is the sport whose governing body announced the introduction of scanners ahead of this year’s Tour de France to check for so-called “mechanical doping” - the use of hidden engines on bikes.

Yet, perhaps more than their contemporaries in many other sports, cyclists are still expected to adhere to a code of honor dictated by the traditions and rituals of the “peloton” - and never more so than during the Tour de France.

For riders, fans and scholars of the Tour’s history, the overall leader’s yellow jersey is a sacrosanct symbol which should not be sullied by allegations of misconduct.

That is what defending champion Alberto Contador is accused of having done on Monday when, on the slopes of the Pyrenees, he appeared to launch an attack at the exact moment that his main rival and “maillot jaune” wearer Andy Schleck’s chain came off.

Tour tradition dictates that if the yellow jersey holder or a contender for overall victory in the race is delayed by a crash or mechanical mishap, his main rivals should wait for him to rejoin the group, the theory being that a great champion should win fairly and squarely, rather than benefiting from the misfortune of others.

It is a practice which has been habitually honored down the years, with Lance Armstrong and his main rival Jan Ullrich making a virtue of waiting for one another during the American’s long years of dominance.

Earlier in this year’s race, Schleck and others benefited from the tradition following a crash during an accident-strewn stage in which senior riders slowed the peloton to allow those affected to catch up, with yellow jersey wearer Fabian Cancellera even negotiating with race officials to cancel the traditional sprint finish because of the unusual circumstances.

By the time he reached the finish on Monday, Contador had gained enough seconds over Schleck to inherit the overall lead and cycling fans were in no doubt the Spaniard had stolen an unfair advantage over his rival, booing him as he was presented with the yellow jersey.

An angry Schleck meanwhile simply vowed revenge, saying: “I wouldn't want to take the jersey like that. I'm not the jury, but for sure those guys wouldn't get the fair play award from me today.”

Contador initially denied wrongdoing, claiming that he had launched his counterattack before Schleck’s chain came off and that he had passed him before he knew what had happened.

But he took a more conciliatory tone in a YouTube apology on Tuesday, admitting that he may have been in the wrong: “The race was in full gear and, well, maybe I made a mistake. I'm sorry. At a time like that all you think about is riding as fast as you can. I'm not happy, in the sense that, to me, fair play is very important.”

Yet even the cycling world is split over whether Contador was right to attack. Some initially suggested that Schleck;s misfortune was owing to the lack of a chain guard - a piece of equipment some riders choose not to use because of the extra weight. But in an interview with the UK's ITV, a Saxobank mechanic said Schleck's bike had been fitted with a chain guard but it had become bent.

What’s more, the incident happened in the heat of the attack, as Schleck, the superior climber, attempted to put Contador under real pressure for the first time in the race. Was the chain slippage then a consequence of the moment?

This after all was one of the most crucial and potentially decisive climbs on the Tour route; not a point when the peloton is rolling through sunflower fields with nothing at stake, when taking advantage of the yellow jersey wearer’s misfortune would have been unthinkable. Great riders are expected to lock horns and race, rather than admire the scenery, when they reach the mountains.

Still, Contador’s critics will argue that his attack can only tarnish his likely victory next weekend in Paris. While Schleck is considered a better climber, Contador is the better all round rider and, having lived with the Luxemburger in the Alps and the Pyrenees, the two-time winner had been expected to gain a decisive advantage in next Saturday’s final time trial, a discipline in which he excels.

There are few competitors in any sport who would disagree that winning is everything - but Contador may be starting to realize that supremacy on a bicycle is the easy part when it comes to riding like a champion.

A mini-breakfast of bacon and sausage, just one of the many free food options in the Tour de France village.

Luckily enough, I have the correct ‘accreditation’ to enter the Tour village, prior to the 10^th stage from Limoges to Issoudun and, despite the drizzly conditions, I am certainly not alone.

It is easy to see why they call it the village. I haven’t located a bed yet, but there is a sufficient amount of food, drink, toilet facilities and entertainment, to provide me with everything I need should I, and the thousands of other privileged enough to have the ‘golden ticket’, get locked in here for the next month.

While the rank and file are being entertained by all sorts of weird and wonderful creatures who form part of the Tour de France cavalcade, I begin my feast-fest by tucking into a couple of mini-pastries.

I decline the offer of some coffee and opt out of the wine-tasting, which seems surprisingly popular considering it is only 10:30am. I am handed the French sports newspaper L’Equipe. It’s a great read, for those who speak French, but as my vocabulary is limited to ‘bonjour’, I fear it is wasted on me.

A man is offering me fruit by the handful. I accept an orange and a little green thing which I think is a sort of plum, very nice it is too, before gratefully scooping up some sweets courtesy of our friends at Haribo.

Bizarrely, I can’t find any water so I decide to partake in an apricot ice drink, which I soon realize is a huge error as my brain freezes up for a good 20 seconds.

There is a crowd gathering around a particular tent, where I notice the genial host/chef is offering up a mini fry-up of bacon and sausages. Imagine, if you will, having to create a breakfast for a doll’s house...then this was it. Bacon was a bit on the fatty side, but that’s just me being ungrateful for no reason.

Before I get stuck into the mini-pasta dishes, I hear a commotion. The riders are beginning to arrive and I’ve got to start work. With regret I leave the much-fancied diet of durum wheat to attend to business, with much food for cycling-based thought.

Astana team cars and vans littered the front entrance which could surely mean only one thing. Lance Armstrong was not only in town for the start of the Tour de France, but staying in the same hotel as yours truly. 

Contador getting in some final practice before the opening Monaco time-trial.

Surely it would only be a matter of time before our paths crossed, before I could flash my CNN pass and grab a quick impromptu interview or take a quick photo.  Well we live in hope.

The hotel is full of devoted Armstrong fans, all sporting the Livestrong brand clothing of their hero and all believing he can deliver a miraculous eighth Tour victory after four years away from the race.

The fans certainly have to be devoted because with beer at $10 and the same for an ice cream, a few days in the south of France for the first couple of stages will leave a big hole in the bank balance.

Hopes of a chance encounter faded as the conceirge dropped a strong hint that just maybe the seven-time  champion was staying somewhere else, away from the hullabaloo. 

Which left the open road, because most of the riders were completing their final preparations by riding the 15.5 km course for the opening individual time trial which begins the Tour on Saturday in the principality.

It will be an important indicator of who is in form for the three-week race and unusually for such a stage being held over a lumpy course as it winds its way up from the harbor at Monte Carlo.

Fractions of seconds lost on corners could prove crucial and Armstrong with his legendary attention to detail will surely be having one last look.

And yes that is the case, but standing in the square in front of the famous Monte Carlo Casino it is very easy to miss a group of fast-moving Astana team cyclists whizzing down in single file.

My partner responds to my plaintive cry  "there's Lance" by capturing the rear ends of the elite of world cycling.  Nice try, but hardly a world exclusive.

Resigned to never capturing that individual moment, away from the press conferences or the official presentation of the teams it left only a quick recee of the start and finish area in Monte Carlo's signature harbor, resplendent with the yachts of the super-rich.

The road up from the harbor rises slightly before heading under the tunnel which is part of the course for the Monaco Formula One Grand Prix. 

Mark Cavendish, the sprint sensation from Team Columbia who is set to bag a host of stage wins and is favorite for the green jersey, suddenly powers past, hunched on his tri-bars.

Then up behind pedals the now-retired Erik Zabel, many times a winner of the green jersey which Cavendish so covets. 

Ken, an ardent cycling fan from England, his wrists chock a block full of Livestrong wrist bands, no prizes for guessing who he's supporting, shouts out his name in recognition and asks for an autograph. Erik pedals on.

But this looks promising, more promising still as I spot an Astana jersey in the distance and heading our way.

More instructions to a very patient partner who fires off a volley of camera clicks. 

The cyclist moves closer. It's not Lance.

But it is Alberto Contador, the Astana team leader and favorite for the yellow jersey. He rides effortlessly by. 

Ken does not seem overly impressed by our close encounter with the man most likely to put one past his hero and this time does not bother to ask for an autograph.

Having to leave to drive north to England just a few hours later (we never did get to see Lance close up,) but Alberto will do, and he's my idea of the race winner.

Will Lance prove me wrong? Well we live in hope.