By Martyn Herman
LONDON (Reuters) - Big guns Bradley Wiggins and Mark Cavendish will bolster the British team for next month's Olympic track cycling program but the powerhouse nation will have its work cut out repeating the supremacy of four years ago in London.
Wiggins, 36, has returned to his track roots and will be a key cog in Britain's team pursuit squad, four years after that glorious summer when he won the Tour de France and the Olympic time trial in a matter of weeks.
He will be bidding for a fifth Olympic gold and fourth on the track after winning the individual pursuit in Athens and team and individual pursuits in Beijing -- before switching his focus to the open road and Tour glory.
Cavendish, meanwhile, has no Olympic medal on his CV -- missing out on the track in 2008 and road race in 2012.
The 31-year-old will arrive in Brazil on a high though after a superb Tour de France in which he won four stages to move his tally to 30, behind only Belgian great Eddy Merckx.
Britain, who won seven of the 10 track titles up for grabs in London, however can no longer call upon it's most successful Olympian Chris Hoy, who has retired as has Victoria Pendleton.
The gap has also closed and Australia, France, the U.S. China, Germany and New Zealand all arrive with medal-hungry squads.
"I think Team GB will be the top nation in the cycling," said Hoy, who won six Olympic golds. "They won't dominate in the same way that we have at the last two Games before Rio 2016 but I am expecting four gold medals and maybe three minor medals."Australia managed only one cycling gold in London and none in Beijing but they look powerful.
Five-times Olympic medal winner Anna Meares, 32, who will carry the nation's flag, will aim to defend her women's sprint title and contest the team sprint and keirin.
"I think I'll be going to Rio in the best physical form I have ever been in my career," Meares said. "It will no doubt be challenging but I'm really excited about this team."
One of the most eagerly-awaited contests will be the men's team pursuit in which Australia beat a Wiggins-powered Britain in a thriller at London world championships.
Wiggins, who will join Olympic champions Ed Clancy and Steven Burke, says the team had stepped up since then and thinks a world record is possible.
"It's no secret we want to win. We're in a really good place and everyone's excited about what we can do," Wiggins said.
"I'm team pursuing better than 16 years ago, better than eight years ago."
Cavendish's selection was controversial after he missed the podium in the omnium at the world championships -- the target he was set by former team boss Shane Sutton.
He has been working tirelessly on the track though and his battle with Colombia's Fernando Gaviria in cycling's equivalent of track and field's decathlon will be compelling.
Gaviria is a double world champion in the seven-discipline event and will be favorite in his first Olympics.
"I want to use every last drop of energy to try and win the Games outright," the 21-year-old told Cycling News.
Britain's reigning champion Laura Trott will be favorite for the women's omnium where American veteran Sarah Hammer will be eyeing a first Olympic gold after two silvers in London.
There will be six sprint and four endurance events on a Rio velodrome that was completed late after problems laying the wooden boards. The six-day program starts on Aug. 11.
(Editing by Greg Stutchbury)