Col du Belvédère

Overview

The Col du Belvédère is a long, patient climb. At 38.4 km it is one of the more marathon-length ascents you can tackle in a single effort, yet its 4.1% average gradient tells you this is a test of endurance rather than raw power. You start at 598 m and finish at 2174 m, a summit high enough to put you well into thin-air territory. The net elevation gain is 1576 m, but the road actually climbs a total of 1663 m — the difference hints at brief descents and false flats woven into the route. Rated Category 1, it sits one rung below hors catégorie, which is exactly what those numbers promise: serious, but survivable if you ride it smart.

How the Gradient Unfolds

Do not be lulled by the 4.1% average. Over 38.4 km, an average that gentle almost always hides sharper reality, and here the max gradient hits 23.82% — a wall steep enough to force even strong riders out of the saddle. The gap between total ascent (1663 m) and net gain (1576 m) means roughly 87 m of the elevation you earn gets given back on downhill sections before being reclaimed. Expect the climb to breathe: long shallow drags where you can settle, punctuated by pitches that spike hard. The shape rewards riders who can hold a steady tempo across the flatter kilometres while keeping enough in reserve for the steep ramps that break rhythm.

Pacing Notes

On a climb this long, pacing is everything. The 4.1% average is deceptive, so anchor your effort to sustainable power rather than gradient. A good rule for a 38.4 km ascent is to ride the shallow sections just below your FTP and let the effort rise only on the steepest ramps, so a brief surge over the 23.82% pitch doesn't blow your whole day apart. If you're unsure where your threshold sits, run the numbers through the FTP estimator before you go — knowing that ceiling turns a guessing game into a plan. With 1576 m of net gain to the 2174 m summit, the closing kilometres at altitude are where discipline pays off.

Gearing

Gear for the wall, not the average. Because pitches reach 23.82%, you want a bailout ratio that keeps your cadence alive when the road stands up. A compact 34-tooth chainring paired with a 34×32 cassette is the sensible starting point for most riders on a Cat 1 climb of this length. If you weigh more, ride less often at threshold, or simply want insurance against fatigue over 38.4 km, go one step easier with a 34×34. That extra sprocket costs almost nothing and buys you the ability to spin rather than grind through the steepest sections near the top.

Summary

The Col du Belvédère is a long-haul Category 1 climb that trades sustained brutality for sheer distance and a couple of savage ramps. Pace it to your threshold, gear for the 23.82% pitches, and respect the altitude at the 2174 m finish.

Length: 38.4 km
Average gradient: 4.1%
Max gradient: 23.82%
Start: 598 m
Summit: 2174 m
Net gain: 1576 m
Total ascent: 1663 m
Category: 1