Port de Larrau

What to Expect from Port de Larrau

Port de Larrau sits in the French Pyrenees and carries an Hors Catégorie rating — the hardest classification a road climb can earn. The numbers justify it. Over 11.4 km you gain 1,348 metres of elevation, starting at 567 m and finishing at 1,564 m, at an average gradient of 8.72%. That average alone puts it in the top tier of Pyrenean climbs, but the 25.17% maximum gradient is the detail that demands respect.

Gradient Profile

An 8.72% average across 11.4 km means there is no soft opening. Unlike climbs that bank easy lower kilometres to flatter the overall figure, Port de Larrau is consistently steep throughout, with the maximum ramp of 25.17% representing a gradient more than double the mean. That kind of spread — average nearly 9%, peak above 25% — signals at least one section where gradient spikes violently away from the norm.

What this means in practice:

• Lower slopes: Expect sustained double-digit gradients early. Do not treat the bottom kilometres as a warm-up at tempo pace — they are already hard.
• Mid-climb: The gradient rarely relents. Any brief easing is recovery to be used, not an invitation to accelerate.
• The ramp: At some point the road hits gradients approaching or exceeding 25%. At that pitch, forward momentum is almost entirely a product of low gearing and controlled power output. Standing and mashing through it costs more than it saves.

Pacing Strategy

With 1,348 m of total ascent and a sustained average above 8%, Port de Larrau punishes early aggression severely. The correct approach is to establish a power target you can hold for the full 11.4 km and defend it rigorously from the bottom.

If you train with power, set your ceiling at or just below your FTP-derived climbing power for efforts of this duration — not your 20-minute number. Estimate your target using the FTP estimator before you arrive. If you ride by feel, the rule is simple: if the first three kilometres feel manageable, you are probably at the right pace. If they feel easy, you are almost certainly going too hard for what comes later.

On the steep ramp sections:

• Drop to your lowest gear before the gradient peaks, not after.
• Keep cadence as high as traction and gearing allow — grinding at 50–55 rpm on a 25% pitch accelerates fatigue disproportionately.
• Use any switchback apex, where gradient momentarily softens, to reset breathing and posture before the next steep pitch.

Gearing Recommendations

This is not a climb where a standard compact (50/34 front, 11-28 rear) gives you comfortable options on the steepest sections. A 34/32 or 34/34 combination is the sensible minimum for most riders. Riders on 1x drivetrains should ensure a 32- or 34-tooth chainring is paired with at least a 36-tooth rear sprocket.

Underestimating the 25.17% maximum gradient when choosing gearing is a mistake that becomes very obvious at the point you need a gear that isn't there.

Final Note

Port de Larrau's HC rating reflects both the length and the relentless gradient. 11.4 km at 8.72% with a 25.17% maximum is not a climb that rewards improvisation. Arrive with a pacing plan, appropriate gearing, and honest expectations about your FTP. Compare it with other Pyrenean HC climbs on Neverchill — see climbs — to put the numbers in context.