Col de Frémamorte / Colle di Fremamorta

Overview

The Col de Frémamorte, known on the Italian side as the Colle di Fremamorta, is an unambiguously hors catégorie ascent. It runs 15.4 km from a start elevation of 1120 m to a summit at 2550 m, a net gain of 1430 m and a total ascent of 1432 m once the small undulations are counted. The headline number is the average gradient: 9.28% sustained across the full 15.4 km. That is not a figure softened by flat run-ins or false flats — it is a relentless, thin-air grind that never gives you a place to hide.

How the Gradient Unfolds

An average of 9.28% over 15.4 km already tells you there is almost no respite, but the max gradient of 24.73% reveals the shape's real cruelty. A climb that averages this steeply cannot be built from gentle ramps punctuated by walls; instead, the steep pitches sit on top of a floor that is already brutally hard. When the road spikes toward that 24.73% maximum, you are accelerating from a base that is itself close to double digits, so the surges arrive with no recovery gradient before or after. Starting at 1120 m and finishing at 2550 m, the second half is also fought in progressively thinner air, which quietly amplifies every percentage point. Treat the whole 15.4 km as one continuous effort rather than a series of separate ramps.

Pacing Notes

On a climb this long and this steep, pacing is everything. With 1430 m to gain at 9.28%, going out even slightly too hard will cost you far more than it does on a shorter ascent. Anchor your effort to your FTP: for most riders, a sustainable target on a 15.4 km HC climb sits a touch below threshold, leaving headroom for the pitches that reach toward 24.73%. If you are unsure of your current number, run it through the FTP estimator before you plan your ride. Meter the steep sections — let your power spike briefly on the 24.73% ramps, then settle straight back to your target rather than chasing the surge.

Gearing

Do not under-gear this one. With a 9.28% average stretched over 15.4 km and spikes to 24.73%, a compact 34-tooth chainring paired with a wide cassette is the sensible baseline. A 34×32 is the minimum most strong climbers will want here, and even then the steepest ramps will have you grinding. If you weigh more, ride at endurance pace, or simply want to protect your knees over 1430 m of climbing, step up to a 34×34 or lower. The extra range keeps your cadence turning on the 24.73% pitches and preserves your legs for the thin air near the 2550 m summit.

Summary

The Col de Frémamorte / Colle di Fremamorta earns its HC rating without argument: 15.4 km at 9.28%, a 1430 m ascent to 2550 m, and ramps that bite to 24.73%. Gear low, pace to your FTP, and respect the altitude.

Length: 15.4 km
Average gradient: 9.28%
Max gradient: 24.73%
Start: 1120 m
Summit: 2550 m
Net gain: 1430 m
Total ascent: 1432 m
Category: HC