The 10 Hardest Climbs in Tour de France History

Road Bike

, by Max Leonard

Mont Ventoux is one of the iconic climbs in cycling is also one of the most difficult. Photography by: A.S.O. / Charly Lopez

The 2023 Tour de France was one of the hardest ever, with relentless days of climbing coming one after the other – which got us thinking. What are the hardest climbs ever featured in the Tour? Taking in historical factors as well as gradients and lengths, here is our top 10.

1. Le Ballon d’Alsace

OK, so these days the 3,865 ft / 1,178m Ballon d’Alsace in the Vosges in north-eastern France is a mere pimple, but this was the first real mountain climb in the Tour. It made its debut in 1905 and was ridden north to south, 5.12 miles / 8.25km at 7% in the middle of a 186 mile / 299km stage from Nancy to Besançon (in 2023 they rode the other, longer side), and was first conquered by crack climber René Pottier. Pottier was – like all his opponents – riding a single-speed bike, and he was the only rider to pedal up the whole thing and not resort to walking.

2. The Col du Tourmalet

The Tourmalet – the Queen of the Pyrenees – first appeared in the Tour in 1910, but it still stacks up with the hardest climbs tackled today. That original climb from Ste-Marie-de-Campan, which starred in both the men’s and women’s Tours in 2023, is 10.3 miles / 16.7km long with an average gradient of 7.4% and over 3,900 feet / 1,200m of vertical ascent; the other side, from Luz-Saint-Sauveur, is 11.22 miles / 18.06km with over 4,250 feet / 1,300m ascent. There had been bicycle races up the Tourmalet as early as the 1890s, but race organiser Henri Desgrange hyped it up, writing that he doubted anyone would make it up (or down again) alive. Octave Lapize, the first man over in 1910, called the race organisers ‘Assassins’ as he came over the top. In difficulty terms, it’s probably edged out by climbs like Col de la Croix de Fer via the Col du Glandon, but the number of champions that have passed over here makes it legendary.

3. Col du Télégraphe / Col du Galibier combo

The Galibier was first climbed in 1911, the year the high Alps were introduced into the Tour. Since then the classic route to the top has been via the Col du Télégraphe – and because there’s a scant 500 vertical feet / 150m of descent between the two, it’s often classed as a single obstacle. Together, they are formidable: over 22.15 miles / 35.65 kilometres, riders will notch up 6,922 feet / 2,110m of climbing with only around 3 miles / 5 kilometres of descent. The Galibier itself averages a 7% gradient, and its upper slopes are particularly moody. Originally, the climb topped out at a tunnel at 8,385 feet / 2,566m, but it was extended to today’s col up a 15% ramp when the tunnel underwent repair in 1979, taking the full height to 8,670 feet / 2,642m. The current KOM on this killer combo is two-time Tour winner Tadej Pogačar.

4. Mont Ventoux

Ventoux, one of the iconic climbs in cycling is also one of the most difficult. The Strava segment stats for the classic route from the Provençal village of Bédoin to the 6,266 ft / 1,910m summit clock in at 12.44 miles / 20.03 kilometres at an average gradient of 7.7%. That’s 1,539m straight up – almost a mile of vertical gain. But, if anything, the numbers do not tell the whole story. The lower reaches through the forest are often stiflingly hot, and the slopes there frequently nudge over 10%. Then, at the Chalet Reynard, the road enters the rocky, barren ‘moonscape’ of white rocks, where the winds can be absolutely fearsome. There’s a great view from the top, sometimes all the way to Mont Blanc, and dedicated climbers who ride all three routes to the top in one day can join the Cinglés du Ventoux club.

5. Cime de la Bonette

At 9,193 feet / 2,802m high, the Cîme de la Bonette is the highest point the Tour de France has ever gone – unsurprising perhaps, since it’s the highest paved inter-valley road in the Alps (‘inter-valley’ as in there are roads that are higher, but they are dead ends). The loop around the Bonette summit (‘cime’) from the real col was added in 1961, as a way of luring tourists to the region, and the Tour rode it the next year, and 1964. But it’s been used very rarely since – 2008 was the last Tour visit, but it did feature in the 2015 Giro d’Italia too. At 15.91 miles / 25.61km, the road from the village of St-Étienne-de-Tinée is the longer climb, through the stunning scenery of the Mercantour national park, but the climb from Jausiers in the north is if anything even more beautiful.

(L) Col du Portet. A.S.O. / Pauline Ballet (R) Col du Galibier. A.S.O. / Charly Lopez

6. Col de l’Iseran

The Col de l’Iseran is the true highest paved road col in the Alps – its 9,068 feet / 2,770m being higher than the Col de la Bonette without its crowning ‘cime’ road. The Strava segment from the ski resort of Val d’Isère is 9.74 miles / 15.67km long, but that’s not the whole story: if you’re in Val, then you’ve already ridden around 15 miles / 24km and climbed 3,400 vertical feet (over a thousand vertical metres) from Bourg-St-Maurice. This lower section is on a busy road, so isn’t that pleasant if you’re not in the pro peloton, but the road above Val d’Isère into the icy wastes is stunning, if difficult, as the altitude really makes itself felt!

7. Puy de Dôme

The Puy de Dôme is a 4,806 ft / 1,465m extinct volcano in the Massif Central, a low range of mountains in central France, and it doesn’t have the length or the height of climbs in the Alps and the Pyrenees. What does it have, then? A single, spiralling road to the top, where there’s a Roman temple to the god Mercury, as well as a visitor centre and a Ventoux-like communications mast. Starting at the town below, where Tour stages usually do, the climb is 8.29 miles /13.34km in total, climbing 3,343 feet / 1,019m, but these last 2.5 miles / 4km are at leg-breaking 11%. Because the summit road is a dead end, it’s always a stage finish, so it’s been the site of some classic battles including, in 1964, between France’s two greatest rivals, Jacques Anquetil and Raymond Poulidor. After a 35-year Tour absence, the Puy was conquered by Canadian rider Mike Woods in 2023.

RELATED: The Puy de Dôme – Return of a Tour Legend

8. Col du Granon

Tucked away at the top of a side road to the south of the Col du Galibier, the Col du Granon is, at 7,917 feet or 2,413 m, the seventh-highest road col in France. It first appeared in the Tour in 1986, when Greg LeMond, who was famously in a battle for domination with Bernard Hinault, put over three minutes into his team-mate and sealed his grip on the yellow jersey. Only one side of Granon is tarmacked, and it features mile after mile of gradients around 10% – rising 3,451 feet (more than a kilometre) in 7 miles / 11.29km. When the Tour visited in 2022 – for only the second time – Tadej Pogačar cracked, losing time to Jonas Vingegaard, and the KOM was taken that day by Romain Bardet.

Ten Hardest Climbs in Tour de France History: Segments 6-10

9. Col du Portet

The Col du Portet (7,267 feet / 2,215m) is the highest road in the Pyrenees, and only the second entry in this list from those mountains. It’s a newcomer to the Tour, having first featured in 2018, in a bizarre 65km-long stage that saw the peloton line up on a grid, F1-style, for a short, sharp race to the top. It didn’t quite produce the expected fireworks, but the climb was so good – by which read, ‘tough’ – they came back in 2020. It gains 4,701 feet / 1,433m over just 9.93 miles / 15.99km, an average gradient of 8.5%, catapulting it into the top 10 hardest Tour climbs.

10. Col de la Loze

The Col de la Loze comes last in this list only by virtue of its novelty; if we were listing in order of toughness, it might well have taken first billing. The 7,559ft (2,304m) pass above the Alpine ski resort of Méribel, was only tarmacked in 2019 ahead of its 2020 Tour debut, and the last 4 miles or so (6km) are a narrow bike path that’s closed to motor traffic. The full climb starts 22.2km earlier in the valley below, but it’s this last stretch that’s truly horrendous – entirely over 9% with ramps up to 24% in the final few hundred metres. It was here that Tadej Pogačar lost five minutes to Jonas Vingegaard in 2023, setting the seal on his Danish rival’s Tour victory.

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