Sigma Sports's guide to the key riders competing for the Tour de France's yellow jersey in 2016. Providing a comprehensive list of who to look out for and what stages they're likely to make their mark on the race.

It's every cycling fan's favourite three weeks of the year again; the Tour de France. The sun is out (in theory) and the world's top riders are coming together for cycling's most prestigious event. We take a look at the riders in contention for the coveted maillot jaune.

The reigning champion has had as good a preparation for this year's Tour as he could have hoped for. First place in the 'mini-Tour' Criterium du Dauphine back at the beginning of June against a stand-out field has put the two-time Tour winner firmly in the favourite spot going into this year's race. However, with a GC contender field packed tighter than a Rapha skinsuit he will have his work cut out for him. Froome will have to trust himself and his team's form in the mountains as, unlike last year, where a particularly windy second stage tore apart the peloton and distanced Nairo Quintana by over a minute and a half, this year will likely be decided in the mountains. Key Stage: Stage 12 - Montpellier to Mont Ventoux 184KM Froome will have fond memories of The Bald Mountain. He won on Mount Ventoux the last time the Tour ventured up its steep slopes back in 2013. This year's trip up to the Weather station takes place on Bastille Day so expect French fans to be even more passionate than usual! Used by Team Sky: Kask Protone Helmet Science in Sport Go Isotonic 60ml Gel Wahoo KICKR SNAP Smart Turbo Trainer

After taking his first grand tour victory at last year's Vuelta, Aru has had a quiet 2016 in preparation for a concerted effort at the Tour. This will be the first time the 25-year-old Sardinian has raced the Tour and he will have the backing of one of the strongest teams in the race. Aru has spent much of the first half of the season training at altitude and will be hoping to assert himself as Astana's main GC hope, especially with rumours circulating that his 2016 Giro d'Italia winning teammate, Vincenzo Nibali, is heading for the new Prince of Bahrain backed team in 2017. Key Stage: Stage 9 - Vielha Val'Aran to Andorre Acalis 184.5KM With a similar Spanish and Andorran parcours to the stage that Aru took the red leader's jersey on at last year's Vuelta, stage 9 will prove to be one of the most decisive of the Tour. Three category one climbs come before a summit finish up to Andorre Arcalis. Here Aru will be looking to attack and make a bid to hold onto the yellow jersey till the peloton reaches the slopes of Mont Ventoux four days later. Used by Astana: Specialized S-Works Evade Aero Road Helmet 2016 Specialized S-Works Tarmac Di2 Road bike 2016 Ceramic Speed UFO 11-Speed Chain

The diminutive Colombian would have likely won last year's Tour with his sparkling attack on stage 20 on the slopes of Alpe d'Huez if it had not been for losing time on the windy stage 2 over the Dutch dykes. This year's Tour route suits the 5'5" 26-year-old as it features only two time trials - one of which is uphill. A minimalistic race calendar over the first half of the season, which included a win at the Tour de Romandie, sees Quintana heading into the Tour with fresh legs and an exceptionally strong Movistar team. Key Stage: Stage 19 - Albertville to Sait Gervais Mont Blanc 146KM The first of the final two brutal mountain stages in the Alpes, Stage 19 features two beastly climbs up to Montee de Bisanne and Saint-Gervais Mont Blanc. Quintana's altitude training will come in handy up the Bisanne with the summit topping out at 1,723m in elevation after a 12.4KM 8.2% average climb. Used by Movistar: Endura FS260 Pro SL Lite Jersey Catlike Mixino Helmet Fizik Arione R1 Braided Saddle

The 31-year-old Tasmanian has had a relatively successful start to his 2016 season at his new BMC team with podium places at Paris-Nice, the Tour Down Under and fourth place finishes at the Dauphine and Volta a Catalunya. The question for Porte and the team is, who's leading the team? Both he and American teammate Tejay Van Garderen have GC ambitions and will be looking for the full backing of their team but just who will support who? Key Stage: Stage 18 - Sallanches to Megeve 17KM This slightly uphill and short time trial will suit Porte who won a similar if slightly steeper uphill time trial at last year's Paris-Nice. If Porte manages to get over his second-week grand tour jinx then this stage will be decisive in his bid for a top-5 finishing spot, especially ahead of two monumental mountain stages on stages 19 and 20. Used by BMC Racing: Giro Synthe MIPS Helmet Powerbar Energize Energy Bar Finish Line Bike Care Wet Weather Value Pack

One of the two French riders looking to perform well on GC, Bardet will be looking to build on his one stage victory and a third place in the mountains classification at last year's race. Runner-up by just 12 seconds at the Dauphine, Bardet has looked the strongest of the French hopes going into the race and an especially mountainous parcours will suit the 25-year-old. Key Stage: Stage 8 - Pau to Bagneres-de-Luchon 184KM This classic Pyrenean stage will be one of the most picturesque and competitive of the entire race with riders taking on the Tourmalet, Val Louron-Azet and Peyresourde. Bardet will look to attack on the Peyresourde and distance the chasing field on the descent as he did in his stage victory at stage 18 of last year's Tour. Used by AG2R La Mondiale: Zipp 404 Firecrest Carbon Clincher Wheels Continental Grand Prix GP4000S II Clincher Tyre Focus Cayo Team Replica Force Road Bike 2016