Col de Rebollion

Overview

The Col de Rebollion is one of those climbs that leaves no room for negotiation. Over 15.5 km it averages a savage 9.86%, hauling you from a start at 384 m all the way to a 1912 m summit. That is a net gain of 1528 m, with 1496 m of total ascent packed into the ride. There is no rolling preamble here and no false valley to catch your breath — the road simply points up and stays there. It carries the HC rating (hors catégorie, the hardest tier above categories 1 through 4), and every one of those letters is earned.

How the Gradient Unfolds

What defines Rebollion is relentlessness. A 9.86% average across 15.5 km means there is almost nowhere to soft-pedal — the mean itself sits close to the double-digit wall that most climbers fear. But the average hides the sting: the gradient spikes to a leg-snapping 21.97% at its steepest. Ramps like that are not just hard, they change your riding — you leave the saddle, fight the front wheel for traction, and grind until the road relents. Because the mean is so high, the shallow stretches that offset those 21.97% pitches are themselves still genuinely steep. Expect to spend the entire 1528 m of vertical either in pain or bracing for the next pitch that brings it back.

Pacing Notes

On a climb this sustained, pacing is everything. The single biggest mistake is treating the lower slopes like the summit is close — it is not, and 15.5 km at 9.86% will find every rider who started too hot. Anchor your effort to your FTP and hold something in reserve for the 21.97% ramps, where power spikes are unavoidable and briefly blow past any steady number you set. Ride the shallower sections as recovery even though they are still steep, and let the wall pitches be the only place you dip into red. If you are unsure what your sustainable number actually is, run the numbers through the FTP estimator before you commit — knowing your ceiling turns 1528 m of climbing from a gamble into a plan.

Gearing

Do not underestimate what 9.86% over 15.5 km, with peaks of 21.97%, demands of your drivetrain. For most riders a compact 34-tooth chainring is the sensible front end, but the cassette is where the decision is made. A 34×32 is the minimum I would take up Rebollion, and even then the steepest ramps will have you at your cadence limit. If your legs or your fitness leave any doubt, fit a 34×34 — the extra sprocket buys you the cadence to keep turning on the 21.97% pitches instead of stalling out. On a climb gaining 1528 m, gearing that lets you spin rather than mash will save your race long before the summit.

Summary

Col de Rebollion is a pure HC test: long, unbroken, and steep from bottom to top, with a summit at 1912 m that only arrives after 15.5 km of genuine suffering. Respect the average, fear the max, and gear for survival.

Length: 15.5 km
Average gradient: 9.86%
Max gradient: 21.97%
Start: 384 m
Summit: 1912 m
Net gain: 1528 m
Total ascent: 1496 m
Category: HC