Collado Larreria

Overview

Collado Larreria is a hors catégorie ascent in Spain, and the numbers make the case on their own. Over 15.4 km the road climbs from 331 m at the base to a summit of 1729 m — a net gain of 1398 m at an average gradient of 9.08%. That average is the headline: sustaining better than nine percent for a quarter of an hour of hard riding is the kind of effort that separates HC climbs from everything below them. With a max pitch of 23.24%, this is not a climb you settle into; it is one you survive in sections and reassemble at the top.

How the Gradient Unfolds

An average of 9.08% across 15.4 km tells you there is very little relief. On a climb this steep, the 9.08% mean is not made of gentle slopes and steep walls averaging out — it is a wall that occasionally leans harder. The 23.24% max sits well above the average, which means the ramps that spike toward it are compensated only by pitches that are still punishingly steep, rarely by true recovery.

Note the two ways the climb's vertical is measured. The net elevation gain is 1398 m — the simple difference between the 331 m start and the 1729 m summit. The total ascent is 1316 m, the sum of only the upward metres. That the total ascent is slightly lower than the net gain is a quirk of how the profile is sampled; either way, you are lifting yourself the better part of 1400 vertical metres with almost no descending to break the rhythm.

Pacing Notes

On a climb this long and steep, discipline early is everything. The temptation on the opening ramps is to chase the riders around you; resist it. Anchor your effort to your sustainable ceiling rather than to the gradient in front of you.

Your FTP is the reference point here. Ride the bulk of the 15.4 km just under threshold, and reserve anything above it for the pitches that climb toward 23.24%, where you have no choice but to spend. If you do not know your number, run the FTP estimator before you commit to a target, because guessing high on a 9.08% average for 15.4 km ends the same way every time — a blow-up with kilometres still to go.

Gearing

Do not underestimate this climb's gearing demands. A 9.08% average with ramps to 23.24% will find the limits of anything too tall. A compact 34-tooth chainring is the sensible front; the question is the cassette.

A 34×32 is the realistic minimum, and even then only strong climbers will spin it comfortably on the steepest pitches. For most riders — and for anyone who wants to protect their legs across the full 15.4 km — a 34×34 is the smarter choice. The extra range keeps your cadence up when the road tilts toward its 23.24% max, which is exactly where an under-geared setup forces you into grinding, muscular efforts you cannot afford to repeat 1398 vertical metres deep.

Summary

Collado Larreria earns its HC rating without argument: 15.4 km, a relentless 9.08% average, and a 23.24% max, lifting you 1398 m from valley to summit. Pace it to your threshold, gear it generously, and treat the steep ramps as the day's real test.

Length: 15.4 km
Average gradient: 9.08%
Max gradient: 23.24%
Start: 331 m
Summit: 1729 m
Net gain: 1398 m
Total ascent: 1316 m
Category: HC