Former Tour de France champions have expressed regret that Lance Armstrong will retire after this year's race.
Armstrong, who has won a record six Tours de France, will retire after competing at this year's event in July.
Five-time winner Eddy Merckx said it was always unfortunate when a great champion decides to leave the sport.
"It's a great personality who leaves the stage after winning six Tours, probably seven, and after beating cancer," Merckx told L'Equipe.
"And that battle with cancer, for me, is his greatest victory."
The 33-year-old Armstrong beat testicular cancer before winning his first Tour in 1999.
Spain's Miguel Indurain, who has also won the showpiece event five times, says preparation for the race gets harder with every year.
"To say you're going to ride the Tour is one thing but to prepare for it is something else," he said.
"It means six months of very hard work for which you can expect no help."
However the Spaniard believes Armstrong could win the Tour for a seventh time.
"I think he still has the ability to win it again this year because if he didn't believe he could he wouldn't have accepted the challenge," he told the Marca newspaper.
"But I also think he will find it more difficult than last year because, although he was very consistent, you could see that he has lost his old explosiveness. However, he will still start as the big favourite.
"At least as far as the Tour is concerned he has won almost everything and if he doesn't win this year it won't matter because he has already earned his reputation."
Another five-time winner Bernard Hinault says doubts over his chances of winning could have affected Armstrong's decision.
"If he wins another Tour, he will be right not to have stopped directly after winning his sixth but if he loses, he will go through the back door," he said.
Tour de France director Jean-Marie Leblanc admitted news of Armstrong's retirement was not a surprise.
"There was probably some weariness, more mentally than physically," he said.
"Nevertheless, as he's a winner and a man of pride, he will come on the Tour with the motivation required to try and win a seventh.
"I find it rather brave when he says he wants to stop on the Tour, and if possible on a seventh victory.
"It's a challenge for himself as much as for his rivals."