Five key stages on the 2018 Tour de France

A look at five of the potentially decisive stages on the 2018 Tour de France which begins on Saturday.

Christopher Froome (left) trains with Team Sky team-mates in Saint-Mars-la-Reorthe, western France. The Tour de France begins on Saturday, July 7.

AFP takes a look at five of the potentially decisive stages on the 2018 Tour de France which sets off on Saturday.

Stage 3 Cholet - Cholet, 35km team time-trial

Chris Froome's Team Sky wilted at last September's Bergen world team time-trial as the 2017 Giro d'Italia winner Dutchman Tom Dumoulin led Sunweb to victory over the 45km route. This one is shorter, and Sky will have thought long and hard about the make up of the team in a tactical balance between the power for here and the lightweight climbers it will need for the slog though the mountains.

Stage 9 Arras - Roubaix, 154 km

Pure climbers will be fretting about their eventual place on the podium when they look at this one with 21km of cobbles, the longest section of them since the 1980s from the fabled Paris-Roubaix classic which require power and endurance with middleweight riders doing well. It starts and ends early to avoid clashing with the World Cup final.

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Stage 12 Bourg Saint-Maurice - Alpe d'Huez, 175 km

Not one, not two but three feared climbs as this Alpine stage tackles the Col de La Madeleine, the Col de la Croix de Fer and the Alpe d'Huez's 21 mythical turns to an eagerly awaited summit finish. With almost 71km in total of climbing, defending champion Froome believes the Tour can be won or lost here and likes the look of it.

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Stage 17 Bagneres-de-Luchon - Saint-Lary-Soulan, col de Portet, 65 km

A short, sharp ride which Tour organisers believe is thoroughly attackable terrain with a stunningly beautiful backdrop and summit finish at 2,215m where the oxygen is rarefied and where only the pure climbers will thrive.

Stage 20 Saint-Pee-sur-Nivelle - Espelette, 31km (individual time-trial)

Froome and Dumoulin, both good climbers and good time triallists if they can get this far, are already on many people's minds when they look at this penultimate stage where a 31km, on-your-own, uphill slog faces all pretenders to the title, the podium and the top 10.