The Tour de France will challenge every aspect of road cycling, with cobbles, hilly finales, mountains, and both a team and individual time trial on the cards for this year’s yellow jersey hopefuls.

If Chris Froome is to secure a fourth consecutive Tour de France win, and achieve a record-equalling fifth career triumph, the Team Sky man will have to prove his all-round ability from July 7 to July 29 2018.

After a slightly tedious start to proceedings for the 2017 race, which saw Marcel Kittel claim five sprint victories in the first 11 stages, organisers ASO have thrown a few curve-balls in to keep things interesting this time out.

But where will the race be won or lost? Where will Froome need to gain time on his rivals, and where might they be hitting back? Here are eight key stages from the 2018 Tour de France route…

Stage three: Cholet – team time trial, 35km

While the first week will, as ever, provide plenty of opportunities for the sprinters and rouleurs, the GC men will also need to be on it from the flag – and their team-mates likewise, given the stage three team time trial in Cholet.

Chris Froome’s Team Sky finished third in the discipline at the worlds in September, over 42.5km, while Tom Dumoulin’s Team Sunweb are the current world champions, and both teams will hope to gain time for their GC leaders in Cholet.

Team Sunweb, team time trial, UCI Road World Championships, 2017, pic - Cor Vos/Team Sunweb

Team Sunweb were crowned world team time trial champions last year - could Tom Dumoulin be in the yellow jersey after stage three of this year's Tour de France?

Team time trials at Grand Tours are nothing new, but the Tour has continued its tradition of including them later in the race (though not quite as late as 2015’s stage nine test), meaning some teams may already be down on numbers.

At 35km, it is a relatively long effort too with a few five per cent climbs to test the legs for good measure. It is not a day where the Tour will be won, but some big names could lose time if they (and their team-mates) are not careful.

Stage six: Brest – Mur de Bretagne, 181km

While the mountainous stages on the 2018 Tour de France parcours do not feature until after the first rest day, there are still some hilly tests thrown into the first week.

Stage six is perhaps the toughest of those, with a double ascent of the Mur de Bretagne to negotiate at the end of a 181km stage.

Aleixs Vuillermoz celebrates the first French victory of the 2015 Tour de France (pic: Sirotti)

Alexis Vuillermoz celebrates victory on the Mur de Bretagne in 2015

The punchy climb, which starts out with gradients in double digits, has featured twice before at the Tour de France and could open up a few (albeit small) gaps overall.

The peloton tackle the 2km ascent, with an average gradient of 6.9 per cent, with 16km remaining before returning to finish on the climb. Cadel Evans and Alexis Vuillermoz were victorious on the climb’s two previous Tour appearances.

Stage nine: Arras – Roubaix, 154km

Cobbles are back on the menu for the 2018 Tour de France, and not just any pavé but the pavé – by which we mean the very same cobblestones as used at Paris-Roubaix.

Of the 15 secteurs included in this year’s race, the 1.4km stretch at Orchies, the 900m Mons-en-Pevele and 1.8km Camphin-en-Pevele will be among those familiar to fans of the Spring Classics.

The final secteur deviates from the Paris-Roubaix course, meaning no Carrefour de l’Arbre, but the Willems a Hem sector (1.4km) is just eight kilometres from the finish line.

Chris Froome conquered the cobbles on stage four of the Tour de France (pic: Sirotti)

The longest stretch of pavé is 2.7km, at Auchy a Bersee, while between the 80km mark and 135km mark, ten of the 15 secteurs have been packed in. There are nearly 25km of cobbles in all – more than ever before at the Tour.

Tony Martin won the last time the cobbles featured at the Tour, while Vincenzo Nibali’s performance over the pavé in 2014 set up his overall victory – there could be some big gaps in the standings come the first rest day.

Stage ten: Annecy – Le Grand Bornand, 159km

The first rest day arrives the day after the Roubaix cobbles have been tackled, and the peloton will need it because from there it’s straight into the mountains.

The Alps are up first, with four climbs packed into the 159km stage ten – including a new mountain for the Tour peloton, the Montee du plateau de Glieres. At six kilometres in length, the average gradient is 11.2 per cent.

Col de la Colombiere, Etape du Tour, sportive, mountains, Alps, riding, training, climbing, climb, ascent, summer, group, Montee du Col des Aravis

The Alps pose the first mountain test of this year's Tour de France and arrive immediately after the first rest day

Alongside that eye-watering gradient, there’s also a rough dirt road to negotiate at the top – though more than half of the stage still remains at that point.

After a brief respite, it’s then up the Col de Romme and finally the Col de la Colombiere before a long descent to Le Grand Bornand. Tasty.

Stage 12: Bourg-Saint-Maurice Les Arcs – Alpe d’Huez, 175km

After the introduction to the Alps on stage ten, stage 11 packs four big climbs into just 108km, including the stunning Cormet de Roseland.

That in itself is likely to be a crucial stage, particularly given the short length and climb-laden profile awaiting, but the peloton will have to keep plenty in reserve for stage 12.

Not only does it mark the return of Alpe d’Huez – 21 hairpins, 13.8km at 8.1 per cent; you know the score – but it is a stage laden with iconic Tour de France giants.

The Tour de France will return to Alpe d'Huez (Pic: Simon Wilkinson/SWPix.com)

The Tour de France will return to Alpe d'Huez

Before the arrival at Alpe d’Huez, the peloton will already have tackled the Col de la Madeleine (25km at 6.3 per cent, peaking at 2,000m) and the Col de la Croix de Fer (29km at 5.2 per cent, reaching a height of 2,067m).

Expect plenty of action, plenty of noise and a wall of colour as the riders then head to the famous switchbacks where this year’s stint in the Alps comes to a spectacular conclusion.

Stage 17: Bagneres-de-Luchon – Col de Portet, 65km

Onto the Pyrenees and, after an introduction to the regions iconic heights on stage 16 comes what could be one of the most intriguing stages of this year’s Tour de France.

Stage 17, from Bagneres-de-Luchon to the Col de Portet is just 65km long, with three climbs packed into that.

Tour de France, 2018, stage 17, profile, Pic - ASO

Up, down, up, down, up (to the highest point of the race) and... done. In just 65km.

The peloton first heads up the Peyresourde – complete with the annex of the Montee de Peyragudes, which caught Chris Froome out as a summit finish in the 2017 race – before the Col de Val Louraon-Azet and then the Col de Portet.

The final climb is 16km long, with an 8.7 per cent average gradient and sections into the double figures at both the start and finish of the ascent.

Any rider caught dallying at the start will pay the price – this will be raced hard and fast and, despite its short length, will be one well worth watching. Organisers have elected for a Le Mans-style grid start too so team tactics will be interesting depending on how spread out their riders are overall prior to the stage.

Stage 19: Lourdes – Laruns, 200km

Compared to stage 17, stage 19 is at the complete opposite end of the spectrum – 200km in length, with the Col d’Aspin, Col du Tourmalet, Col des Borderes and Col d’Aubisque to test the climbing legs.

It is the final mountain stage of the 2017 race, so you can expect two races to develop – one in the large breakaway, where climbers bid for their final chance of a stage win, and one further back where the GC men do battle on the iconic Pyrenean climbs.

Peaking at 2,115m, the Col du Tourmalet’s return after a one-year absence for 2017 is among the key highlights – 17.2km at 7.4 per cent for this year’s race, as opposed to the full bottom-to-top challenge.

Pace yourself, as burning out early will really cost you on the final climb (Pic: ASO)

Etape du Tour 2014 - Pau / Hautacam - 20/07/214 - Ambiance - Les coureurs dans le col du TOURMALET - Photo ASO/EVA/Eric Vargiolu

It is unlikely to be the most critical ascent, however – peaking just over halfway through the stage – with that honour instead bestowed on the final climb, the Col d’Aubisque.

The steepest section of the climb is the final kilometre, where the last rites for some GC challenges will be read.

Stage 20: Saint-Pee-sur-Nivelle – Espelette (ITT), 31km

With the mountains done and dusted, all that remains before the traditional Paris finale is the stage 20 time trial – though the GC men can not afford to leave their climbing legs in the high mountains.

The 31km test against the clock is a punchy one, with a lumpy route punctuated by the Cote de Pinodieta at 28km and a small rise to the finish line too.

Chris Froome was first and second at the two Tour de France time trials (pic: Sirotti)

If Chris Froome is in contention come the stage 20 time trial, he will find a course well suited to him

If Tom Dumoulin and Chris Froome have sufficiently recovered from their Giro d'Italia exploits and are in contention overall, this will be an intriguing test of both men’s ability on a course perfectly suited to each of them.

At the other end of the scale, Romain Bardet saw his 2017 Tour de France challenge fade on a shorter time trial in Marseille on the penultimate stage – so much so that he nearly dropped off the overall podium. There will be time for some last twists and turns in the GC, that is for sure.