Alto de Las Iglesias

Overview

Alto de Las Iglesias is a genuine hors catégorie test, the kind of climb that rewards patience and punishes bravado. Over 13.6 km it drags you from a valley floor at 964 m up to a summit at 2032 m, a net gain of 1068 m. The average gradient sits at a stinging 7.88%, and there is a moment where the road ramps to a brutal 18.74%. This is not a climb you survive on fitness alone; it demands a plan.

At HC difficulty, Las Iglesias sits above the categorized scale entirely (harder than a Category 1), and the numbers explain why. Nearly 14 kilometers at almost 8% offers no meaningful respite, and the total ascent of 1039 m confirms that what you climb, you keep. There are no long descents to bail you out here.

How the Gradient Unfolds

The signature of this climb is consistency broken by cruelty. With a 7.88% average stretched across 13.6 km, most of the ascent lives in that punishing 7-to-9% band where you are always working but never quite recovering. The gap between the 7.88% average and the 18.74% maximum tells the real story: somewhere on this mountain the road rears up more than twice as steeply as its overall pitch.

That 18.74% spike is where races are won and amateur dreams end. Whether it arrives early, when your legs are fresh, or late, when they are hollow, it forces a decision. The difference between net gain (1068 m) and total ascent (1039 m) is small, which means there is almost no rolling relief woven into the profile. You climb, and you keep climbing.

Pacing Notes

Treat Las Iglesias as an exercise in restraint. On a sustained HC effort of this length, your best defense is riding just under threshold and refusing to chase early accelerations. Anchoring your effort to a percentage of your FTP keeps you honest across all 13.6 km rather than blowing apart on the lower ramps.

A workable approach is to hold a steady tempo through the consistent 7.88% sections and accept a brief overshoot on the 18.74% wall, then settle back down. If you do not know your threshold number, run it through the FTP estimator before you ride so your pacing math is grounded in reality, not optimism. With 1068 m of vertical to absorb, a controlled start pays dividends near the 2032 m summit.

Gearing

Do not under-gear this one. A 7.88% average over 13.6 km, punctuated by an 18.74% ramp, calls for a compact setup and a wide cassette. A 34×32 is the sensible minimum for strong climbers who can hold a high cadence and stay seated through the steep pitch. For most riders, though, a 34×34 is the smarter choice, giving you the extra spin to protect your knees and preserve energy for the summit push to 2032 m. When the road hits 18.74%, that final sprocket is the difference between grinding and grinding to a halt.

Summary

Alto de Las Iglesias is a summit worth earning: long, steep, and unforgiving from base to top, with a max ramp that demands respect and gearing to match. Pace it with your FTP in mind, gear low, and let the 7.88% average do its slow work.

Length: 13.6 km
Average gradient: 7.88%
Max gradient: 18.74%
Start: 964 m
Summit: 2032 m
Net gain: 1068 m
Total ascent: 1039 m
Category: HC