Col de l'Iseran - France
The Col de l'Iseran is the highest paved mountain pass in the Alps. It stands at 2,770m and tops the list of the very high mountain crossings. It connects the French cycling heartlands of the Tarantaise and the Maurienne valleys and sits deep into the mountains nestled close to the Italian border. A ride from Bourg St Maurice to the north to Modane to the south is just shy of 100km.
Despite the superlatives of this pass in terms of mountain scenery, its very remote location and Tour de France fame, the Col de l'Iseran does not enjoy the same cult status than the Galibier or Alpe d'Huez. This is a real shame because this is a ride of superlatives - not so much in numbers but in the feeling the road exudes. The core climb is super, almost lovely, tougher from Bonneval from the south than from Val d'Isere but it is the surroundings of the high mountains around the pass and the pass road that drills deep into the mountain give the Col d'Iseran its specific character.
But despite being deep in the mountain and so high, the pass does not feel as remote as some others in this category. This is mainly because activity has spread all the way to the pass height from the north and all the way to the start of the core climb from the south. The ski resort of Val d'Isere is visible for almost all of the northern ascent bar the last 3.5km and lifts go even past the pass height. The south is wilder and more remote but the Haute Maurienne valley is a working valley and has villages dotted along the way till the very end. The road never feel far away from activity.
Col de l'Iseran 2,770m - Northern ascend from Val d'Isere
If you start from Val d'Isere which is at an altitude of 1,830m, the climb is 16.7km long and covers 970m elevation gain with a manageable average gradient of 5.8%. Starting from Val d'Isere, you can leave all the road stress behind and focus on what really matters - climbing an awesome pass road. There are three distinctive sections to this route, not too dissimilar to how the Galibier climb from Valloirer is structured.
Deep into the valley to 2050m altitude
The first 5km from Val d'Isere with an elevation gain of 230m go along a straight road next to the l'Isere stream deep into the Isere valley before the road turns sharply up the hill to the right. If you hiked from here deeper into the valley and over the Col de la Loze, you end up in Italy at Lake Seru and the Colle del Nivolet. The Col de l'Iseran is sort of the sister pass to the Nivolet and it shares the same tremendous and beautiful surroundings. But back to the Isere valley we are riding through. Once you leave Le Fornet - the last outpost of Val d'Isere - behind, the valley immediately quietens down. It is a reasonably tight valley and the road runs above the Isere stream. Halfway down, the ramps and switchbacks of the route up the hillside ahead come into view on the right.
Long vertical up through lovely switchbacks
For the next sections up to 2,520m altitude, the road climbs in switchbacks up the mountainside high above the Isere valley. Val d'Isere in always in view and the route feels going upwards rather than forwards. The road climbs 480m over 7.8km so the gradients are never crazy. The higher you climb, the better the view of the valley below and the mountains above becomes, many are over 3,000m in height. This stretch of road goes right through the ski area and is also used as piste in winter. There are quite a few cable car and other lift installations around but if you look past them, this is a fabulous road. There are 7 switchbacks on this stretch and also a couple of very long ramps up to 3km long. As you see Val d'Isere below, this road feels less remote until it turns for the last 3.5km to the right onto a high expanse towards the pass.
Deep into the mountain and to the top at 2770m
The last 3.5km and 260m climbing are through a wide expanse between the Signal d'Iseran (3,237m) to the left and the Pointes des Lessieres (3,043m) to the right. The road drives straight forward, hugging the right side of this expanse. If it would not have been for the ski installations, this is a really remote part of the French Alps. Bourg St Maurice is 50km to the north of the pass and Lanslebourg in the Haute Maurienne Valley is 33km to the south. To the East is the Grand Paradiso National Park in Italy and to the west are just mountains up to 3,800m high. The gradient tightens up somewhat but stays below 10% apart form the final switchbacks at the top. The altitude is more of an issue as this is the highest pass in the Alps, higher than the Stelvio. The fact that the gradient is not crazy make you take in the majestic nature and solitude of the mountains even more.
Col de l'Iseran from Val d'Isere
Length: 16.3km
Altitude gain: 930m
Max altitude: 2770m
Average gradient: 5.7%
Max gradient: 15%
Route tip: Although the recognised starting point from the north is in Bourg St Maurice, starting from Val d'Isere is highly recommended. The 31km from Bourg St Maurice to Val d'Isere are truly horrendous and if you don't have a death wish, this road should be avoided at all cost. It is busy with heavy traffic and trucks plus a number of tight tunnels thrown in which give a cyclist nowhere to go.
Starting form Val d'Isere makes a double ascent doable. A round trip down the southern side to Bonneval sur Arc is around 60km and 1950m climbing. As the southern side is wilder and more spectacular, this will make for an unforgettable ride.
