Unai Pass

Overview

Unai Pass is a long, high-altitude category 2 ascent that stretches 20.6 km and lifts you from 2436 m at its base to a summit of 3265 m. The headline gradient is a modest 4.03% on average, but that number hides the real story: this is a climb defined by its length and its elevation, not its steepness. With 829 m of net gain and 790 m of total ascent, the profile is remarkably consistent, meaning almost every metre you climb is climbed forward — there are no significant descents to give the legs a breather. The thin air above 2400 m is the hidden opponent here, quietly taxing your effort long before the gradient ever does.

How the Gradient Unfolds

At 4.03% average across 20.6 km, Unai Pass reads on paper as a steady tempo effort, and for long stretches that is exactly what it is. The near-identical figures for net gain (829 m) and total ascent (790 m) confirm a road that climbs almost monotonically, without rollers or false flats stealing your rhythm. The sting lives in the maximum pitch of 10.28%, roughly two and a half times the average. Expect the road to sit comfortably below its mean for much of the way, then rear up into short ramps that brush that 10.28% ceiling. These are the moments to respect — they are where a poorly judged early effort comes back to punish you.

Pacing Notes

On a climb this long, pacing is everything. The consistent 4.03% grade rewards riders who hold a steady, sustainable power rather than surging on every rise. Anchor your effort to your FTP and aim to sit just below it for the bulk of the 20.6 km, keeping a small reserve for the ramps near 10.28%. If you don't have a current number, run a quick check with the FTP estimator before you go. Factor in the altitude too: at 3265 m the summit sits high enough that your sustainable power will fade compared with sea level, so start conservatively — the final kilometres, deep into 829 m of accumulated climbing, are where discipline pays off.

Gearing

Because Unai Pass is defined by duration rather than brutal steepness, gearing should prioritise a comfortable spin over 20.6 km rather than survival gearing for a single wall. A compact setup paired with a wide cassette is ideal. A 34×32 will handle the 4.03% average with ease and cover most of the pitches toward 10.28%. If you tend to grind, or you're carrying fatigue from earlier climbing, a 34×34 gives you that extra sanctuary gear to keep the cadence up on the steeper ramps without redlining. At altitude, a lighter gear that protects your legs is almost always the smarter choice.

Summary

Unai Pass is a patient rider's climb: 20.6 km of steady, high-altitude effort that gains 829 m and tops out at 3265 m. Respect the length, meter your effort against the 4.03% average, and keep something back for the 10.28% ramps and the thin air near the top.

Length: 20.6 km
Average gradient: 4.03%
Max gradient: 10.28%
Start: 2436 m
Summit: 3265 m
Net gain: 829 m
Total ascent: 790 m
Category: 2