Boca del Paso

Overview

Boca del Paso is a category 1 climb that packs a serious punch into 10.3 km. Starting from just 41 m above sea level and topping out at 938 m, it delivers a net elevation gain of 897 m over its length. The average gradient of 8.7% is the number that matters most here: this is not a climb with generous flat recovery stretches. It leans on you from bottom to top, and the 18.67% maximum gradient marks a wall that will have you out of the saddle whether you planned to be or not.

With a total ascent of 877 m recorded across the route, almost every metre of forward progress is also a metre upward. That density is what earns Boca del Paso its category 1 status — one rung below the hardest hors catégorie label, but firmly in the territory where a climb becomes a genuine test rather than a warm-up.

How the Gradient Unfolds

The defining trait of Boca del Paso is consistency of difficulty rather than a single hard spot. An 8.7% average across 10.3 km means the road rarely gives you a breather, and the gap between that average and the 18.67% max tells you the steepest ramps are more than double the typical slope. Expect the gradient to swing upward in short, sharp kicks layered on top of an already demanding baseline.

Because the net gain (897 m) sits close to the total ascent (877 m), there is very little descending or false-flat inside the climb. What goes up mostly stays up. Plan your effort around sustained climbing punctuated by those steeper pitches rather than any meaningful recovery.

Pacing Notes

The smartest way to ride Boca del Paso is to anchor your effort to your FTP. At 8.7% average over 10.3 km, this is a long enough climb that going too deep in the opening kilometres will cost you dearly near the 938 m summit. Aim to hold a steady percentage of threshold on the baseline gradient, then allow your power to spike briefly over the 18.67% ramps before settling back.

If you are not sure of your current threshold, run the numbers through the FTP estimator before you commit to a target. Knowing your ceiling turns a suffer-fest into a repeatable, well-judged effort.

Gearing

For a climb averaging 8.7% with ramps to 18.67%, gear low and keep cadence up. A compact 34-tooth inner chainring paired with a wide cassette is the sensible baseline. A 34×32 will get most trained riders up the sustained sections while leaving a little in reserve, but on the steepest pitches you will be grateful for anything lower. If your legs favour spinning over grinding, or you are carrying fatigue, step up to a 34×34 — that extra sprocket makes the 18.67% wall far more manageable and protects your knees over 897 m of climbing.

Summary

Boca del Paso is a concentrated, unrelenting category 1 climb: 10.3 km that almost never eases, topped by ramps steep enough to break a rhythm you have worked hard to build. Gear low, pace off your threshold, and respect the average — it does the damage long before the summit.

Length: 10.3 km
Average gradient: 8.7%
Max gradient: 18.67%
Start: 41 m
Summit: 938 m
Net gain: 897 m
Total ascent: 877 m
Category: 1