Colle Intersile sud m.2077

Overview

Colle Intersile sud is a hors catégorie climb that earns its rating without qualification. Over 11.3 km it averages 10.16%, dragging you from a start elevation of 931 m to a summit at 2084 m. That is a net gain of 1153 m, with 1127 m of total ascent packed into a road that barely relents. Averages like this are rare — 10.16% sustained for more than eleven kilometres is the kind of number that separates a hard climb from a genuinely brutal one. When the steepest pitches spike to 16.48%, you understand quickly that there is nowhere on this ascent to truly recover.

How the Gradient Unfolds

The defining feature here is consistency of difficulty. With an average of 10.16% and a maximum of 16.48%, the road never offers the flat "false summits" or descending kickbacks that let you catch your breath on many long climbs. The gap between the average and the max is modest, which tells you the hard sections are not isolated ramps stitched between easy stretches — the whole climb sits in a narrow, steep band. Expect long stretches hovering around and above 10%, punctuated by pitches climbing toward that 16.48% ceiling. Because net gain (1153 m) exceeds total ascent (1127 m) only slightly, there is virtually no downhill relief across the full 11.3 km. You climb, and then you keep climbing.

Pacing Notes

On a climb this relentless, pacing is survival. With no recovery gradients, going into the red early is a mistake you cannot undo — there is no soft section ahead to bail you out. Anchor your effort to your FTP and aim to hold a steady percentage of it from the base rather than surging on the steeper ramps. If you do not know your threshold, run the numbers through the FTP estimator before you attempt this one, because misjudging your ceiling on an 11.3 km wall at 10.16% average will cost you dearly in the final kilometres. Ride the steep pitches near 16.48% seated where possible, and let your cadence, not your ego, dictate the tempo. The summit at 2084 m rewards patience.

Gearing

Do not under-gear this climb. An average of 10.16% over 11.3 km with ramps to 16.48% demands compact, climbing-friendly ratios. A 34×32 is the sensible minimum for strong climbers, but most riders will be far better served by a 34×34, which keeps your cadence up and your knees intact when the road tilts toward 16%. If your setup allows an even easier bailout gear, bring it. On a wall this sustained, having one more sprocket in reserve is the difference between spinning to the top and grinding to a halt.

Summary

Colle Intersile sud is a pure hors catégorie test: long, steep, and unforgiving from the 931 m base to the 2084 m summit. Come with the right gearing, a disciplined pacing plan, and respect for the numbers.

Length: 11.3 km
Average gradient: 10.16%
Max gradient: 16.48%
Start: 931 m
Summit: 2084 m
Net gain: 1153 m
Total ascent: 1127 m
Category: HC