Col de la Loze

Overview

Col de la Loze is a hors catégorie climb, the hardest rating on the scale (HC, then 1, 2, 3, 4), and the numbers make the case plainly. Over 19.8 km the road lifts you from 839 m at the base to 2260 m at the summit, a net elevation gain of 1421 m at an average gradient of 7.17%. That average alone would earn respect, but the more revealing figure is the total ascent of 1912 m — nearly 500 m more than the net gain. That gap tells you this is not a smooth, uniform drag. The climb rolls, dips, and pitches, forcing you to gain, surrender, and regain altitude across its length. It is a full hour or more of climbing for most riders, and it earns every letter of its HC label.

How the Gradient Unfolds

The single most important thing to understand about Col de la Loze is that discrepancy between total ascent and net gain. With 1912 m climbed but only 1421 m of net gain, roughly 491 m of your effort is spent clawing back elevation lost to intermediate descents and false flats. A steady 7.17% average therefore hides a far spikier reality: sections that ease off or even tip downhill are paid for later with ramps well above the average. Treat the posted 7.17% as a bookkeeping figure, not a promise. Your legs will feel long stretches steeper than that number suggests, punctuated by brief moments of relief that break rhythm rather than restore it.

Pacing Notes

On a climb of this length and irregularity, discipline early is everything. The temptation is to chase the moments where the gradient relents, but those are the places to recover, not attack. Anchor your effort to your FTP and aim to hold a sustainable percentage of it across the full 19.8 km rather than surging on every ramp. Because the profile keeps handing back elevation, riders who go out hard in the opening kilometres pay for it dearly in the upper reaches where the air thins toward 2260 m. If you are unsure of your threshold, run the numbers through the FTP estimator before you commit to a target, then ride to that ceiling with a little in reserve for the steepest late pitches.

Gearing

Gear for the ramps you cannot see on the average, not the average itself. For most riders a compact 34-tooth inner ring is the starting point, paired with a wide cassette. A 34×32 will get many fit climbers up, but given 19.8 km, 1912 m of total ascent, and pitches that run well over 7.17%, a 34×34 buys valuable insurance for the late, high-altitude ramps. If your setup allows an even larger sprocket, take it — spinning a low gear at cadence protects your legs across an hour-plus effort far better than grinding a gear that is one tooth too tall.

Summary

Col de la Loze is a long, irregular HC test where the gap between net gain and total ascent defines the suffering. Pace to threshold, gear generously, and respect the ramps hiding inside the average.

Length: 19.8 km
Average gradient: 7.17%
Max gradient: n/a
Start: 839 m
Summit: 2260 m
Net gain: 1421 m
Total ascent: 1912 m
Category: HC