Some, like Canadian Ryder Hesjedal, crashed en route and have the scars to prove it.
Flying off your bike at close to 70 kilometres per hour into a tangle of bodies, machinery and unforgiving tarmac is hardly an ideal entree to the Summer Games. But such is the harsh world of elite road racing, where breaking down your body is par for the course.
"It's a hard sport," Hesjedal said dryly from his home in Girona, Spain.
The 31-year-old from Victoria was hurt July 6 during the sixth stage of the Tour, one of at least two dozen riders caught up in a nasty crash with 26 kilometres left on the day.
In the carnage of the crash, the Giro d'Italia winner went down and suffered road rash to his hip, knee and ankle. But the real damage came when, upon impact, his leg slammed into another rider's bike.
"Just like a baseball bat being swung into your leg," Hesjedal said by way of description.
At six foot two and 159 pounds, wearing only a thin uniform, there's not lot of padding.
A bloody Hesjedal, who started the day in ninth place overall, picked himself up and finished the ride. He had fallen 99 places in the standings.
"When you're getting crashed that way and people are on top of you and you've taken the energy of other riders all together, the body doesn't stand up very good," he told The Canadian Press.
"But in the big picture, I'm very lucky. I didn't break anything or have any major tearing of something. It's just unfortunate the one main thing just didn't let me function properly so I could really race at that point."
That thing would be his leg.
The impact occurred just below his hip — "the crease in the leg where you're pedalling."
"Once there's hematoma damage in there, the leg just doesn't function properly," he added.
Hesjedal withdrew from the race and returned to Spain. Amazingly, after a travel day, he was back on a home training bike the next day for an hour.
"Kind of the worst thing you can do is stop completely for a few days and let the leg seize up," he said.
He kept adding to his daily routine on the bike — one hour on the trainer, then two hours on the road then three, then four.
That was accompanied by daily therapy.
As his leg loosened, there was more pain elsewhere — this time in the ribs. Spasms that were another hangover of the crash.
But Hesjedal says his body is recovering well.
"I feel good on the bike," he reported. "It's hard to say unless I did a world-calibre race tomorrow where the real feeling is."
Hesjedal, who was scheduled to leave Monday for London, will find out soon enough at the Olympics. He races July 28 in the road race and Aug. 1 in the individual time trial.
Unlike Beijing, where he was accompanied in the road race by fellow Canadians Michael Barry and Svein Tuft, Hesjedal will be on his own in London.
The world governing body of the sports allocates Olympic berths by points. They are hard to come by at the elite level because Canada has so few top riders. And, according to Barry, Canada did not enter enough riders in continental competition to help make up the shortfall.
So while countries like Australia, Britain, Italy and Spain are able to enter five-man teams in London's road race, Canada has just Hesjedal.
A disappointed Barry, who came ninth in the 2008 road race, will root Hesjedal on from the sidelines.
"I think it's a disappointment really for all the Canadian professionals and especially given how well Ryder has performed this year," Barry said from his home in Spain.
"It's a shame for him, because it would have been great for him to go there with a couple of teammates this year. Because obviously with a couple of teammates our chances of getting a great result there would have been much better. It's too bad really."
Hesjedal, who finished 55th in Beijing after spending some time in a large breakway group, will be a lone wolf.
"He'll just have to race conservatively until the right moment and then try and strike," said Barry. "But he's at the mercy of many of the other teams. He can't really rely on anybody.
"There's no one there to help him out and keep him in position. And that's something we've been able to do together in the past."
The time trial is more straightforward. Everyone is on their own, riding against the clock.
Hesjedal is a good time trialist but he will be up against a field that includes a slew of specialists in the discipline.
Hesjedal, whose nickname is "Weight of a Nation," is no stranger to shouldering Canadian cycling hopes.
"It's a little more true for the Olympics, for sure when it's just you out there representing the country in the race," he said of his nickname. "But I don't feel it in a negative way, that's for sure.
"I'm honoured to get that spot and go out there. I think I'm capable of representing Canada well, I'll thrive on everyone's support."
In recent months, that groundswell has grown and grown.
"It's incredible," he said. "I already felt that support before the Giro. But since doing what we did in Italy, it's pretty overwhelming the following and the support that I get.
"I was definitely upset to have to leave the Tour knowing people were behind me and wanting to see me do well. That was tough but I think it's something that has to happen sometimes. . . . It's a tough sport and it doesn't always go according to plan. That's the way life is, also."