Colle Barant

Overview

Colle Barant is an hors catégorie monster, the kind of climb that redefines what your legs think they can do. Over 33.8 km it lifts you from a valley floor at 349 m all the way to a summit of 2385 m — a net gain of 2036 m and a total ascent of 2020 m once the small dips are counted back in. The headline number is an average gradient of 6.03%, which sounds civilised until you remember it is sustained for well over an hour, and that the same road spikes to a wall of 26.95% somewhere along the way. This is an endurance climb first and a steepness climb second, but it never lets you switch off.

How the Gradient Unfolds

Think of Colle Barant less as a single slope and more as a long, uneven staircase. The 6.03% average is a blend: stretches of gentle false flat where you can breathe, alternating with pitches that bite hard. The difference between the 2036 m net gain and the 2020 m total ascent tells you the road briefly gives elevation back — small descents or flats that interrupt the grind. Those moments are a gift and a trap. They let you recover, but they also lull you before the gradient snaps upward again, culminating in ramps as severe as 26.95%. Nearly 2 km of vertical over 33.8 km means the climbing is spread thin on paper yet concentrated wherever those steep sections land.

Pacing Notes

On a climb this long, discipline beats bravado. Set your effort by your FTP and hold it steady — the 33.8 km will punish anyone who surges early. Aim to spend most of the climb just under threshold, saving a small reserve for the 26.95% pitches where staying seated may be impossible. If you do not know your threshold, run the numbers first with the FTP estimator so you climb to a target rather than to feel. From 349 m to 2385 m the air thins noticeably near the top, so expect your sustainable power to sag in the final third and plan your pacing so that fade is built in, not a surprise.

Gearing

Gear for the steepest moment, not the average. A 6.03% mean is manageable, but the 26.95% max demands a bailout ratio that keeps your cadence alive. A compact 34-tooth chainring paired with a wide cassette is the sensible baseline: 34×32 will get most fit riders up the sustained sections, while 34×34 gives you the extra rescue gear for the sharpest ramps and the thin air above 2000 m. Over 2036 m of gain, spinning a slightly easier gear preserves the muscular reserves you will desperately want in the last kilometres.

Summary

Colle Barant is a full HC test — long, high, and spiked with a brutal maximum gradient. Pace it by threshold, gear it for the steepest pitch, and respect the altitude, and those 2036 m of climbing become an achievement rather than an ambush.

Length: 33.8 km
Average gradient: 6.03%
Max gradient: 26.95%
Start: 349 m
Summit: 2385 m
Net gain: 2036 m
Total ascent: 2020 m
Category: HC