Sydney - Simon Gerrans, who won two stages of the Tour de France and is the only Australian to have won two of cycling's one-day classics, has announced he will retire at the end of the 2018 season.
Gerrans is one of only seven Australians to have worn the leader's yellow jersey in the Tour de France.
He also won stages of the Giro d'Italia and the Spanish Vuelta and won the Milan-San Remo and Liege-Bastogne-Liege races which are among cycling's five one-day classics, which are collectively known as the Monuments.
In an open letter published on Tuesday on the website of his BMW Racing Team, Gerrans said he was ready to change careers.
"Although I feel that I am still performing at a good level physically, my passion for the sport is not what it used to be," he said.
"Professional cycling is too hard unless you are able to commit wholeheartedly."
Gerrans, who turned professional in 2005, rode the Tour de France for the BMC team this year.
He finishes with 33 career victories, winning his home tour - the Tour Down Under - four times.
"When I look back over my racing career my fondest memories don't come from winning Classics or Grand Tour stages but the happiness and joy my victories created for the team and people close to me," Gerrans said.