Boca de Chavao

Overview

Boca de Chavao is a genuine hors catégorie test of endurance. It starts at sea level — a clean 0 m — and doesn't stop rising until you reach the summit at 2081 m. That is a net gain of 2081 m spread across 32.2 km of road, with total ascent measured at 2080 m. There is almost no false flat to hide behind here: the climb averages 6.46% from bottom to top, and because it begins at the coast, it delivers the full sea-to-summit experience in a single, uninterrupted effort.

At more than 32 km, this is a climb you settle into rather than attack. The scale is what defines it. Very few ascents ask a rider to gain over two thousand metres in one continuous push, and Boca de Chavao is squarely in that rarefied HC company.

How the Gradient Unfolds

The headline average of 6.46% is deceptively steady, but the road is not uniform. With a maximum gradient of 12.75%, there are ramps that bite well beyond twice the average. Those steep pitches are where the climb hides its teeth — short walls that spike your effort before the grade eases back toward the mean.

Because the average sits at 6.46% while the max touches 12.75%, you can expect the climb to breathe: sustained mid-single-digit stretches punctuated by sharper kicks. Over 32.2 km, even a one- or two-percent variation swings your speed noticeably, so reading the road ahead matters as much as raw fitness.

Pacing Notes

On a climb this long, pacing is everything. The single biggest mistake is treating the early slopes like the whole thing is a 6.46% cruise — the 2081 m of vertical will punish anyone who overreaches in the first third.

Anchor your effort to your FTP. For a climb of this duration, riding just below threshold on the steady sections and allowing brief surges over the 12.75% ramps keeps you efficient without blowing up. If you don't know your number, run it through the FTP estimator before you plan your day. Then divide the 32.2 km mentally into thirds and hold something in reserve for the upper slopes, where thinner air near 2081 m makes the same wattage feel harder.

Gearing

Gear for the length, not just the average. A 6.46% mean over 32.2 km will grind you down long before the 12.75% ramps do, so err toward easier ratios. A compact 34-tooth front paired with a wide cassette is the sensible baseline: 34×32 gives most riders enough range to spin the steady sections comfortably. If you climb at a lower cadence, carry extra weight, or want insurance for the steepest pitches, step up to 34×34 — that extra sprocket is cheap comfort over a two-thousand-metre ascent and keeps your knees intact near the top.

Summary

Boca de Chavao is a sea-to-summit HC climb that rewards patience, smart pacing and generous gearing. Start at the coast, respect the 12.75% ramps, and ride the 6.46% average like the long game it is — all the way to 2081 m.

Length: 32.2 km
Average gradient: 6.46%
Max gradient: 12.75%
Start: 0 m
Summit: 2081 m
Net gain: 2081 m
Total ascent: 2080 m
Category: HC