Sir Bradley Wiggins wants Tour de France and Giro d'Italia double
Sir Bradley Wiggins says winning the Giro d'Italia could be tougher than his historic 2012 Tour de France victory.
Wiggins also reiterated his desire to defend his Tour de France title rather than play a support role for Team Sky team-mate Chris Froome.
With the Giro d'Italia starting on Saturday, the 33-year-old Wiggins said: "It's a huge challenge, probably bigger than the Tour de France.
"The Tour de France is my focus, it's just that I'm doing the Giro before."
Wiggins will need to improve his record in the Italian race if he is to stand a chance of becoming the first cyclist since Marco Pantani in 1998 to win both the Giro and Tour de France.
The Briton has competed in the Giro four times and finished 40th the last time he competed in the three-week race around Italy in 2010.
However, since then he has become the first British rider to win the Tour de France, following up that success two weeks later by claiming a fourth Olympic gold medal with victory in the men's time trial at London 2012 in August.
"It's like last year and the Olympics," he continued. "I was focused on that and the Tour. This year the Giro comes first."
Wiggins admitted there had been a lot of talk of him riding in support of Froome but that it was a decision "for the team management to decide".
"We are both on different paths and we're both professionals," said Wiggins. "We have been there before. We're on the same team and know what needs to be done.
"I would be comfortable in a supporting role but it's not like I'm going to ride 200km on the front and swing off and lose 30 minutes. I want to be there at the death, I want to be on the podium."
Froome, 27, finished second and acted as a valuable support in helping Wiggins to win the famous French race last year and wants to step up as Team Sky's main rider to try to claim victory himself in 2013.
Team Sky boss Dave Brailsford said in November 2012 that Froome was likely to be selected as Tour de France leader, although the the plan had not "completely been signed off".
But, after Wiggins stated his desire to defend his crown, Brailsford said the problem of choosing between the two is one he will "relish".
The 100th edition of the race this year features several tough ascents in the Alps and Pyrenees which are likely to suit climbers such as Froome, while the time trials at which Wiggins excels have been reduced to 65km from 100km in 2012.
Wiggins added: "Somebody will need to make that decision. It will be quite hard, and I'm glad it's not me, but Dave is good at it."
The exploits of Wiggins saw him claim the 2012 BBC Sports Personality of the Year award and, despite his heightened profile, he insists he has retained his focus on cycling.
"My saving grace is that I haven't gone out and tried to cash in on the Olympics and got my face everywhere - got on game shows and all this stuff - like most of them have done," he said.
"I went back to work on 1 January. I've been out there grafting with my team. I've gone back to trying to do what we do best - and that's trying to win bike races."