Col de l'Alpette

Overview

Col de l'Alpette is a Category 1 climb in France that earns its classification through sheer cumulative punishment rather than relentless steep gradients alone. At 21.1 km from base to summit, with a net elevation gain of 1254 m and a total ascent of 2265 m, this is not a climb you pace by feel. The 5.94% average gradient sounds manageable until the road throws a 32.88% ramp at you — one of the sharper maximum gradients you will encounter on any Category 1 ascent.

The gap between total ascent (2265 m) and net elevation gain (1254 m) tells an important story: this climb has significant undulation baked in. Expect sections where the road flattens or briefly descends, only to kick back up again. Those relief sections are not rest — treat them as opportunities to recover and top up glycogen before the next sustained effort.

How the Gradient Unfolds

Starting at 322 m elevation and finishing at 1576 m, the climb covers a wide elevation band across its 21.1 km. The 5.94% average is skewed downward by the flatter or rolling passages embedded in the route, which means the sustained climbing sections run considerably steeper than that headline figure suggests.

The 32.88% maximum gradient is extreme — a near-vertical wall by road cycling standards. Ramps at that pitch are rarely long, but they demand full commitment: seated climbing becomes nearly impossible for most riders, and maintaining momentum through the transition onto such a gradient is critical. Hit it too fast and you blow up; enter it too slowly and you stall.

Key gradient zones to anticipate:

• Lower slopes: The base at 322 m tends to serve as a warm-up zone on many long Alpine climbs. Use the early kilometres to settle into a sustainable FTP-based effort — target roughly 70–80% of threshold for a climb this long.
• Mid-section undulations: Where the road rolls, resist the urge to surge. Keep cadence high, recover, and treat these segments as active rest rather than an invitation to attack.
• Upper ramps including the 32.88% spike: Shift down well before you reach the steepest pitches. Running out of gears on a 30%+ ramp with 5 km to go is a race-ending mistake.

Pacing Notes

At 21.1 km, Col de l'Alpette is long enough that any early aggression will cost you badly in the final third. The correct approach is even power, not even speed — your pace will naturally slow on the steep ramps, and that is fine provided your watts stay consistent.

If you are unsure of your current threshold power, use the FTP estimator before planning your target watts for this climb.

The 2265 m of total ascent versus 1254 m net gain also means your legs are absorbing more work than the summit elevation difference implies. Factor this into your fuelling strategy: at 21.1 km, you are looking at 60–90+ minutes of sustained effort for most trained cyclists, which means on-bike nutrition is non-negotiable.

Gearing Recommendations

The 32.88% maximum gradient sets the floor for your gearing requirements. A compact chainset (50/34) paired with an 11-32 or 11-34 cassette is a sensible minimum. Riders on a standard 53/39 setup will find the steepest pitches extremely difficult unless they are exceptionally strong climbers. Do not underestimate this climb based on the 5.94% average — gear for the worst sections, not the mean.

Final Assessment

Col de l'Alpette rewards disciplined riders who respect its length and treat its variable gradient as a technical challenge rather than a simple slog. The Category 1 rating is justified. Nail your pacing in the first half, anticipate the steep ramps, and keep something in reserve for the upper kilometres.