|Tour de France 2015|
|Dates: 4-26 July|
|BBC coverage: Live text commentary of every stage online and radio commentary on BBC 5 live sports extra or online from 14:45 BST|
Alberto Contador hopes his body will hold up as he tries to become the first man since 1998 to win the Giro d'Italia and Tour de France in the same year.
The Spaniard, 32, is also aiming to become just the third rider to hold all three Grand Tour titles after winning the Vuelta a Espana in August 2014.
No rider has ever won all three Grand Tours in the same calendar year.
The Tour starts on Saturday. Contador said: "In my head I feel motivated. How my body will react is a new challenge."
Italian rider Marco Pantani was the last rider to win both the Giro and the Tour in 1998.
Tinkoff-Saxo rider Contador, who won the Tour in 2007 and 2009, faces one of the strongest line-ups in recent years when the 102nd edition of the three-week race begins in Dutch city Utrecht on Saturday 4 July.
Defending champion Vincenzo Nibali of Italy, Britain's 2013 winner Chris Froome and Colombian runner-up from that year Nairo Quintana are also in the field of 198 riders.
|The big four's Grand Tour bests|
|Rider||Giro d'Italia||Tour de France||Vuelta a Espana|
|Chris Froome||34th (2009)||1st (2013)||2nd (2011, 2014)|
|Alberto Contador||1st (2008, 2015)||1st (2007, 2009)||1st (2008, 2012, 2014)|
|Vincenzo Nibali||1st (2013)||1st (2014)||1st (2010)|
|Nairo Quintana||1st (2014)||2nd (2013)||36th (2012)|
"If I were to win the Tour full stop, it wouldn't change my career so much but something that people can remember is winning the Giro and the Tour in the same year," said Contador who would become the eighth man to win the Grand Tours of Italy and France in the same year.
He attempted the double in 2011 but his results - first in the Giro and fifth in the Tour - were annulled after a positive doping test. He also lost his 2010 Tour title.
Contador said that this year's Tour, which features cobbles and tough climbs in the opening week, followed by punishing mountain ascents in the Pyrenees and Alps, will be the toughest he has taken on.
"It's hard and it's going to be fundamental not to crash or fall off," he said.
"I was worried that I wouldn't recover well from the Giro, but I have done. Both my head and body are in good shape. Now it's up to me to take the Tour day by day."
Contador, Froome and Nibali all started last year's Tour but Froome pulled out on stage five with a broken wrist, while Contador exited on stage 10 after fracturing his right leg, leaving Nibali to win the race by almost eight minutes.
Pantani was the last rider to win the Giro-Tour double, while Belgian legend Eddy Merckx won four successive Grand Tours in 1972-73 and Frenchman Bernard Hinault three in 1982-83.