Chris Froome's absence looms large over the Tour de France as contenders size up one another in what promises to be an open edition of the race.

Australian Richie Porte was quick to declare defending champion Geraint Thomas the "clear favourite", with Team Ineos again boasting a formidable line-up, although others clearly believe they have a better chance than usual this July.

Trek-Segafredo's Porte can perhaps afford to talk freely, with the pressure off his shoulders after a disappointing start to the season during which he has been plagued by illness.

But the former Team Sky rider clearly expects his old bosses to be celebrating again come Paris.

"I think Thomas is the clear favourite," Porte said. "He won it last year, and he's probably in better shape this year, too

"With the team that (Ineos) have and their other card, Egan Bernal, a wonder kid who can do everything, I think the pressure is on them."

Movistar have arrived at the Tour with a powerful line-up that includes Nairo Quintana, Mikel Landa and world champion Alejandro Valverde.

Team boss Eusebio Unzue believes this is their chance to win a race that has eluded the team since 2006, when Oscar Pereiro won in Caisse d'Epargne-Illes Balears colours.

"We are ambitious in a difficult Tour, like everyone else, and a Tour that is more open for Froome's absence," Unzue said.

But AG2R La Mondiale's Romain Bardet, second to Froome in 2016, said the fact the four-time winner was not involved did not change anything from his perspective.

"There is no big change for me," he said. "This is the biggest race in the world, and we are here facing other riders who are at 100 per cent.

"I would not offend those who are here by saying we have an opportunity because others are not."

Bardet, along with Groupama-FDJ's Thibaut Pinot, is one of two Frenchmen given a serious chance of ending what is now a 34-year wait for a first home winner since Bernard Hinault.

With French fans increasingly impatient, the x-factor for either could be external pressure.

During his run to second place in 2016 and third in 2017, Bardet seemed to carry it comfortably but should he pull on the yellow jersey he may find it weighs heavily.

"As Frenchmen, it's a long wait since Bernard Hinault's last win for sure but I'm accustomed to trying to deal with that the best I can," Bardet said.

"I think it's good for us as French people to have guys who can try to go for the win in the Tour, and in the end, we have big, big support on the road. I think it can strengthen our riders during the Tour."

But while Froome's absence robs the Tour of an engaging story – the 34-year-old would have been gunning for a record-equalling fifth victory – the question is whether it will change the nature of the race.

"Maybe people have a fear of Froome," Porte said. "Last year they didn't attack that much. It definitely changes it a lot.

"To have (Froome and Tom Dumoulin) out, second and third in the Tour last year, it's a totally different ballgame."

But Bardet's manager Vincent Lavenu disagrees.

"For me, it doesn't change things that much," Lavenu told PA. "Ineos is still as strong collectively. They have Bernal who's an incredible bike rider, they have Thomas who's the defending champion.

"They have riders like (Michal) Kwiatkowski, (Wout) Poels, (Dylan) Van Baarle, so the team is still full of heavyweights – it doesn't change much."

Change would certainly suit Porte, who has seen his own hopes of glory in the Tour hit by crashes, mechanicals and illness over recent years.

"Maybe the Tour de France owes me something," the 34-year-old told PA. "Hopefully, the cycling Gods smile on me this year."