Portella de Mentet

Overview

Portella de Mentet is an hors catégorie monster, the kind of climb that earns its HC rating on length and gradient alone. Over 24.2 km the road drags you from a start elevation of 435 m to a summit at 2429 m — a net gain of 1994 m — while averaging a punishing 8.26%. That average is the headline number, but it undersells the challenge: an 8.26% mean sustained for nearly a full marathon of distance is the sort of effort that separates riders who pace intelligently from those who blow apart before the halfway mark. With a max gradient of 23.17%, this is a climb that demands respect from the first pedal stroke.

How the Gradient Unfolds

The shape of Portella de Mentet is defined by its sheer relentlessness. Total ascent registers at 1959 m, slightly below the 1994 m net gain, which tells you almost every metre of the 24.2 km tilts upward — there is very little false flat or recovery to reset your legs. An 8.26% average across that distance means long stretches sit well into double digits, and the 23.17% max is the spike that will force you out of the saddle or into your easiest gear entirely. Expect the gradient to ratchet rather than surge: sustained walls of steepness punctuated by pitches even steeper still. The absence of meaningful descents means your average power output has nowhere to hide.

Pacing Notes

On a climb this long, pacing is everything. Ride the lower slopes at an effort you could hold to the summit 24.2 km away, not the effort that feels comfortable in the first kilometre. A sensible target is a percentage of your FTP that leaves headroom for the 23.17% ramps, where power inevitably spikes. If you push too hard early, the back half — still climbing hard toward 2429 m — will crush you. If you don't know your threshold, use the FTP estimator to set realistic numbers before you commit to the effort. Break the 24.2 km into segments and treat each as its own climb; the summit at 2429 m is a long way from the 435 m start, and mental pacing matters as much as physical.

Gearing

Do not under-gear this one. With an 8.26% average dragging on for 24.2 km and a 23.17% max lurking, you want the widest range you can bolt on. A compact 34-tooth chainring paired with at least a 34×32 cassette is the minimum most riders should consider, and many will be far happier with a 34×34 to spin the steepest ramps without wrecking their knees. On an HC climb, a lower gear is not weakness — it is the difference between finishing strong and grinding to a walk on the 23.17% pitches.

Summary

Portella de Mentet is a true hors catégorie test: long, steep, and unrelenting from 435 m all the way to 2429 m. Pace it, gear it, and respect it.

Length: 24.2 km
Average gradient: 8.26%
Max gradient: 23.17%
Start: 435 m
Summit: 2429 m
Net gain: 1994 m
Total ascent: 1959 m
Category: HC