At 10.3% average over 8.7 km, Mont du Chat is no postcard climb: it’s one of Savoie’s most brutal and technical ascents, towering nearly 900 m above Lac du Bourget.
An hors catégorie wall with no let-up
From Le Bourget-du-Lac, the road climbs 8.7 km for 905 m of elevation gain, at a fearsome 10.3% average. Few flat stretches offer relief: the hairpins come in quick succession through dense forest, with sections close to 12-13% that leave no room to recover before the summit, which opens onto a spectacular panorama over Lac du Bourget and the surrounding ranges.
A rare, feared road in racing
Mont du Chat has been climbed by the Tour de France only twice in its entire history: in 1974, and again in 2017. During that latter appearance, on stage 9, the technical, narrow descent on the far side was marked by a spectacular group crash, triggered by a race convoy motorbike braking suddenly, which brought down Australia’s Richie Porte, forcing him to abandon with an injury.
Getting the ride right
A compact or triple crankset is strongly advised to hold the gradient over the full distance without blowing up. Brakes in perfect condition matter just as much: the technical, winding descent demands constant vigilance, especially on a wet road.
When to go
April to October, as the road is generally rideable from spring onward given the modest altitude of the summit. May and September offer pleasant conditions, with limited traffic on weekdays.
Good to know
Chambéry, some fifteen kilometres away, makes a convenient base for reaching other climbs in the area such as Grand Colombier or the Chartreuse, while the shores of Lac du Bourget offer a scenic spot to recover after the effort.
