Best results 2015: Tirreno Adriatico (1st), Tour of the Basque country (4th), Route du Sud (2nd)
Wins in 2015: 2
Best grand tour results: Tour de France (2nd, 2013), Giro d'Italia (1st, 2014)
Last year's Tour: did not take part
After skipping the race last year to focus on the Giro d'Italia, which he won, Quintana is back on the Tour with a good chance of becoming the first Colombian to prevail. A remarkable bike handler, he likes to launch long-range attacks in the mountains, which could prove lethal to his rivals on a very hard course.
Chris Froome, Britain
Best results 2015: Vuelta a Andalucia (1st), Tour de Romandie (3rd), Criterium du Dauphine (1st)
Wins in 2015: 6
Best grand tour results: Tour de France (2nd, 2012; 1st, 2013), Vuelta (2nd, 2011, 2014)
Last year's Tour: abandoned, stage five
The 2013 champion has yet to reproduce the form that took him to the title but he was the strongest in the Criterium du Dauphine, the most prestigious warm-up race for the Tour. The first week of the race, with cobbles and possible strong winds, just like last year, will be tricky to handle for Froome as his Sky team have shown they do not always deal well with the unexpected. His confidence is growing after a tough start to the season that saw him crash in the Fleche Wallonne classic.
Alberto Contador, Spain
Best results 2015: Vuelta a Andalucia (2nd), Volta a Catalunya (4th), Tirreno-Adriatico (5th), Giro d'Italia (1st), Route du Sud (1st)
Wins in 2015: 4
Best grand tour results: Tour de France (1st, 2007, 2009), Giro d'Italia (1st, 2008, 2015), Vuelta (1st, 2008, 2012, 2014)
Last year's Tour: abandoned, stage 10
He might not have the same legs as when he first won the race eight years ago, but Contador has the flair and the experience to achieve the first Giro/Tour double since Marco Pantani in 1998. The Spaniard will seize every opportunity to aggress his rivals, on all terrains -- that often proves decisive on a grand tour.
Vincenzo Nibali, Italy
Best results 2015: Tour de Romandie (10th)
Wins in 2015: 1
Best grand tour results: Tour de France (1st, 2014; 3rd, 2012), Giro d'Italia (1st, 2013; 2nd, 2011; 3rd, 2010), Vuelta (1st, 2010; 2nd, 2013)
Last year's Tour: 1st
Has had a difficult year as his Astana team faced the possibility of being stripped of their World Tour status, meaning he could have been deprived of the chance to defend his title. He seems to be on the way up, showing glimpses of his offensive best in a Criterium du Dauphine stage in June, and winning his second straight Italian national title last weekend. The first week of the Tour could help him make ground on his rivals, just like last year when he impressed on the cobbles.
Thibaut Pinot, France
Best results 2015: Tirreno-Adriatico (4th), Criterium International (2nd), Tour de Romandie (4th), Tour de Suisse (4th)
Wins in 2015: 2
Best grand tour results: Tour de France (3rd, 2014), Vuelta (7th, 2013)
Last year's Tour: 3rd
Improved steadily since his stage win on his Tour debut in 2012, showing immense climbing capacities to finish third overall last year, also claiming the white jersey for the best under-25 rider. Won two of the biggest mountain stages of the season in week-long races in the Tour de Romandie and the Tour de Suisse. Maybe too green for victory this year, but a real threat if he emerges unscathed from a treacherous first week.
Joaquim Rodriguez, Spain
Best results in 2015: Tour of the Basque country (1st), Fleche Wallonne (4th), Liege-Bastogne-Liege (3rd), Criterium du Dauphine (8th)
Wins in 2015: 3
Best grand tour results: Tour de France (3rd, 2013; 7th, 2010), Giro d'Italia (2nd, 2012; 4th, 2011), Vuelta (3rd, 2010, 2012; 4th, 2013, 2014)
Last year's Tour: 54th
With almost no individual time trial in this year's Tour, the diminutive climber finally has a favourable terrain to have a decent chance of reaching the top. He could be sheltered by a strong Katusha team in the first week if they do not give the priority to sprint specialist Alexander Kristoff.
Tejay van Garderen, United States
Team: BMC Racing
Best results in 2015: Tour of Oman (2nd), Criterium du Dauphine (2nd)
Wins in 2015: 1
Best grand tour results: Tour de France (5th, 2012, 2014)
Last year's Tour: 5th
The American often has an off-day on the Tour but appears to be stronger this year. Van Garderen, the race's best under-25 rider in 2012, underlined his credentials by finishing second overall in the Criterium du Dauphine. He is more of a defensive rider, which could cost him in a race that should favour the attackers.