Colle Las Arà

Overview

Colle Las Arà is a genuine hors catégorie test, the kind of ascent that earns its HC rank not through a single wall but through relentless accumulation. Over 15.9 km the road lifts you from 418 m at the base to a summit of 1601 m, a net gain of 1183 m. The average gradient sits at 7.42%, and that number rarely lets up long enough for a real breather. This is a climb you settle into for the better part of an hour, not one you attack in bursts.

How the Gradient Unfolds

The headline figure is that 7.42% average, but averages hide the sharpest teeth. Here the road spikes to 18.35% at its steepest, more than double the mean, so expect ramps that momentarily wreck any comfortable rhythm you have built. With a net elevation gain of 1183 m spread across 15.9 km, the arithmetic is unforgiving: there are few flat metres to recover on. The total ascent of 1153 m tracks closely to the net gain, meaning the profile is almost entirely upward with little in the way of false descents to reset your legs. Treat every gentler section as a gift and the steep pitches as the price of admission.

Pacing Notes

On a climb this long, discipline beats bravado. Aim to hold an effort just under your threshold for the opening two-thirds, then decide whether you have the reserves to push the final kilometres. Your FTP is the anchor here: knowing it lets you set a wattage ceiling and avoid detonating on one of the 18.35% ramps early. A useful target on an HC ascent of 15.9 km is a steady tempo that you could, in theory, sustain to the 1601 m summit without a single soft-pedal. If you are unsure of your number, run the FTP estimator before you commit to a pacing plan. Ride the average, respect the spikes, and let the gradient dictate your cadence rather than your ego.

Gearing

Gear for survival, not for pride. With sustained 7.42% slopes and pitches to 18.35%, most riders will want a compact chainring paired with a wide-range cassette. A 34×32 is a sensible baseline that will carry strong climbers through the mean gradient without cross-chaining under strain. But given the length and those double-digit ramps, a 34×34 buys you a meaningful extra margin, letting you spin rather than grind when the road kicks toward its 18.35% maximum. Over 1183 m of climbing, that lower bailout gear is the difference between a rhythmic ascent and a muscular grind that empties your legs before the summit.

Summary

Colle Las Arà rewards patience, pacing, and honest gearing. It is a long HC effort defined by a stubborn 7.42% average and a vicious 18.35% peak, delivering 1183 m of vertical over 15.9 km. Come prepared to ride within yourself and the summit at 1601 m will feel earned.

Length: 15.9 km
Average gradient: 7.42%
Max gradient: 18.35%
Start: 418 m
Summit: 1601 m
Net gain: 1183 m
Total ascent: 1153 m
Category: HC