Planche des Belles Filles

Overview

Planche des Belles Filles is a category 2 climb that covers 14.1 km at an average gradient of 5.32%. On paper that number reads as moderate, but the average hides the real story: this is a road that never settles. Over its length you gain 748 m of net elevation, rising from a start point at 395 m to a summit at 1143 m, while the total measured ascent comes to 714 m. The headline figure that everyone remembers, though, is the maximum gradient of 19.35% — a wall steep enough to rearrange your whole plan for the day.

How the Gradient Unfolds

Do not let the 5.32% average lull you. A climb that lifts you 748 m over 14.1 km with a peak of 19.35% is, by definition, uneven. Long stretches sit below the average to keep that mean honest, which means the steep sections must climb well beyond it to balance the books. Expect the profile to breathe: shallower drags where you can hold a rhythm, punctuated by sharp ramps that force you out of the saddle. The gap between the 5.32% average and the 19.35% maximum — nearly 14 percentage points — is your warning to always leave something in reserve. The final wall is where the climb earns its reputation, and where riders who spent everything early come undone.

Pacing Notes

The smart way to ride 14.1 km of variable gradient is to pace off effort, not speed. Anchor your climb to your FTP and treat the average sections as the place to bank time, riding just under threshold so you have headroom for the ramps toward 19.35%. If you do not know your threshold number, run it through the FTP estimator before you go so your targets reflect reality rather than optimism. On the steepest pitches your power will spike well above your steady figure — that is fine and unavoidable, but keep those surges short and recover on the flatter grades. With 748 m of climbing to absorb, a controlled first half almost always beats a heroic one.

Gearing

A 19.35% maximum gradient makes gearing a genuine decision, not an afterthought. For most riders, a compact 34-tooth inner chainring paired with a wide cassette is the sensible baseline. A 34×32 will get many climbers up the steepest ramps if your threshold power is strong and your cadence holds, but on a climb this pitchy a 34×34 buys you the extra margin to keep spinning when the road tips toward 19.35% late, with tired legs. If you are unsure, size down: over 14.1 km, the ability to keep turning the pedals smoothly matters far more than saving a few grams.

Summary

Planche des Belles Filles rewards patience and punishes ego. Pace it off your threshold, gear it for the 19.35% wall rather than the 5.32% average, and save something for the top. Get those three things right and its 748 m of climbing becomes a challenge you finish strong.

Length: 14.1 km
Average gradient: 5.32%
Max gradient: 19.35%
Start: 395 m
Summit: 1143 m
Net gain: 748 m
Total ascent: 714 m
Category: 2