Chris Froome says he has already re-focused on Vuelta a Espana

Four-time Tour de France champion Chris Froome says he has already re-focused his thoughts on October's Vuelta a Espana.

Froome was surprisingly left out for the Tour de France which began in Nice on Saturday after struggling for form as he continues his comeback from an horrific accident last year.

The 35-year-old Briton will join the Israel Start-Up Nation next season, ending a glittering decade with Team Sky/Ineos, but is determined to leave with a solid Grand Tour in his legs.

"Obviously I would have liked to have been (at the Tour de France)," Froome told ITV during their coverage of this year's opening stage around the city of Nice.

"That was the goal since the big crash last year, that was the carrot to get myself back in shape and racing again.

"But I think what it boils down to is at the Criterium de Dauphine two weeks out from the Tour I wasn't feeling like I normally would feel coming in to the Tour. At that point it made more sense to re-adjust, move the goalposts and re-focus on targetting the Vuelta."

While he would not have been in the form to target a record-equalling fifth Tour de France, Froome said he would have been prepared to help Egan Bernal retain his title.

"I was willing to go in and help Egan and help the guys try and win another yellow jersey, but it made more sense to take this extra time to build up for the Vuelta," he said.

Froome confirmed he would ride in the Tirreno-Adriatico and train at altitude ahead of the Vuelta which starts on Oct. 20 and promises a brutal route.

"I'm mentally prepared for it, I know the roads up there are brutal, nothing flat, pretty much up and down all day," said two-time Vuelta winner Froome of a route that will concentrate on the rugged terrain of north-west Spain.

"The Vuelta trumps the other Tours in brutal uphill finishes."

Froome said his move to the relatively new Israel Start-Up Nation team will begin a new chapter in a career and offer a very different challenge to what he has been used to at a dominant Team Sky/Ineos where he has enjoyed high-class support.

"Next year will be a very different project and to try to replicate what I've been used to for 10 years won't make sense," he said. "Not necessarily having that train in the mountains is going to be the way.

"Maybe it will help me experiment a little bit more with a new team and express myself a bit more in my riding style."