In a brief video message at the launch of the Giro d’Italia on Wednesday, Chris Froome confirmed he will bid for a grand slam of major Tour victories by attempting to win the 2018 Giro. After securing victory in the Tour de France and Vuelta a España this year, the four-times Tour winner will have his eyes on a third consecutive Grand Tour triumph.

“It’s a unique situation for me, having won the Tour and Vuelta and now having the opportunity to go to the Giro and attempt to win a third consecutive Grand Tour,” Froome said. “It’s something the team have considered carefully and we’ve talked about a lot. We know it would be a significant feat in the modern era to win both the Giro and the Tour in the same season, but the way we managed things this year gives me confidence I can successfully target both races.”

Froome rode the Giro in 2009 and 2010 but that was before his dramatic transformation into a major Tour contender in 2011 – he was disqualified in 2010 for hanging on to a motorbike on a climb – meaning that his attempt to win the Giro will mark a leap into the unknown for him and Team Sky. The British squad have rarely ridden convincingly at the Italian race, with Sir Bradley Wiggins falling short in 2010 and 2013, and Richie Porte’s attempt in 2015 also going awry.

That makes the stakes extremely high. Froome will not race in the 2018 Vuelta but if he were to win the Giro that would put him level in the record books with Eddy Merckx and Bernard Hinault, the only two riders in history to have won three Grand Tours in a row. It would also put him in the elite group to have won all three Grand Tours: Spain, Italy, France. After the Giro, Froome will go on to target a fifth Tour de France win, which would put him level with Jacques Anquetil, Merckx, Hinault and Miguel Induráin.

The Giro-Tour double is rarely achieved, however, and has not been done since the late Marco Pantani managed it in the EPO-fuelled era in 1998. Confirmation Froome will attempt to win both in 2018 marks a departure for Team Sky, who have achieved a run of success in the Tour de France by taking a relatively conservative approach, following essentially the same buildup since Wiggins’s victory in the Critérium du Dauphiné in 2011.

Planning the Giro-Tour double will call for Froome to be in form early in the season, something which he does not usually do, and for him to race through potentially bad weather, which does not suit him. It also means he will have to peak both in late May – for the usual mountainous final week of the Giro – and late July, although the six-week gap between the Giro and Tour, one week longer than usual, could enable him to back off then “rebound”.

The 2018 Giro route will suit Froome, as it does not have the long time trials that would favour the 2017 winner Tom Dumoulin. It does include eight summit finishes that favour the Sky rider, including one on top of the extremely tough Monte Zoncolan, plus a dirt-road excursion over the Colle del Finestre. But by quitting his tried-and-tested approach Froome could be placing that coveted fifth Tour de France victory in jeopardy.

One possible incentive is a rumoured fee of €2m to induce Sky to put Froome on the start line, a draw that would have obvious attractions for the Israeli hosts of the start on 4 May. Another is the fact Sky have been criticised over the years for their overly pragmatic, machine-like approach and that this has tempted the team and their leader to take a risk and try for what could be a cycling jackpot.