Col de Vernaz

Overview

The Col de Vernaz is a category 1 climb that stretches 16.5 km from a base at 795 m to a summit at 1834 m. That is a net elevation gain of 1039 m over the full distance, delivered at an average gradient of 6.3%. Category 1 sits just below hors catégorie, so this is a serious mountain effort — long enough to demand patient pacing, steep enough to hurt if you rush it, and sustained enough that there is nowhere to truly hide.

What defines Vernaz is its length and consistency rather than any single wall. At 16.5 km, most riders will be climbing for the better part of an hour, and the challenge is holding a repeatable effort deep into that time rather than surviving one savage ramp.

How the Gradient Unfolds

The headline number is a 6.3% average across 16.5 km. The total ascent recorded on the road is 1010 m, marginally less than the 1039 m net gain between base and summit — a reminder that the climb trends relentlessly upward with little in the way of false-flat relief or downhill respite. In practice, expect long stretches sitting close to that 6.3% mean, with the gradient breathing a little above and below it as the road bends and the slope eases and bites.

Because the average is so honest, Vernaz rewards riders who treat it as one continuous tempo effort. There is no dramatic mid-climb plateau to bank a recovery, so the smart play is to meter your energy from the first kilometre as though every kilometre after it looks the same — because, more or less, it does.

Pacing Notes

On a climb this length, pacing is everything. Your FTP is the anchor: on a 16.5 km ascent that will take most riders around an hour, target a sustainable percentage of threshold rather than chasing early heroics. Going out even slightly too hard on the lower slopes compounds badly over 1039 m of climbing.

If you are unsure of your threshold, run the numbers through the FTP estimator before your attempt and set a realistic power ceiling for the day. Aim to reach the 1834 m summit with something left, not to arrive at the halfway mark already redlined. On the 6.3% average, small surges cost far more than they gain — steady wins here.

Gearing

For a sustained 6.3% grade over 16.5 km, gear for endurance, not bravado. A compact chainset paired with a wide-range cassette is the right starting point. A 34×32 will cover most fit riders who can hold tempo comfortably, giving you a low enough ratio to spin the steeper pinches without grinding.

If you tire late in a long climb, expect the last kilometres to feel harder, or simply want insurance for a climb that never relents, step up to a 34×34. That extra cog preserves cadence when fatigue sets in over the final metres toward 1834 m, and on a climb this length, protecting your legs early pays back at the top.

Summary

The Col de Vernaz is a long, honest category 1 climb: 16.5 km at 6.3%, gaining 1039 m to a 1834 m summit. Pace it as a single steady effort, gear low, and respect its length.

Length: 16.5 km
Average gradient: 6.3%
Max gradient: n/a
Start: 795 m
Summit: 1834 m
Net gain: 1039 m
Total ascent: 1010 m
Category: 1