Coll de l'Aubaga

Overview

Coll de l'Aubaga is a hors catégorie ascent that earns its rating the honest way: length, sustained steepness, and altitude all stacked together. Over 18 km the road climbs from 767 m to a 2179 m summit, a net gain of 1412 m, with 1401 m of total ascent logged along the way. The near-identical net and total figures tell you this is an almost relentlessly upward road — there is little in the way of descent or flat to recover on. At an average gradient of 7.83%, it sits firmly in the range where the climb never really eases, and the 22.54% maximum warns that at least one pitch will force you well out of any comfortable rhythm.

How the Gradient Unfolds

Think of this climb in terms of its shape rather than any single number. The 7.83% average across 18 km means the "typical" stretch already demands respect, but averages hide the spikes. With a maximum of 22.54%, the hardest ramp is nearly three times steeper than the mean, so the effort profile swings sharply. The tiny gap between 1412 m of net gain and 1401 m of total ascent confirms there are no meaningful false descents to reset your legs — every metre climbed is a metre kept. Practically, that means you climb continuously from the 767 m base toward the 2179 m top, and the thin air of the final third compounds whatever the gradient throws at you.

Pacing Notes

At 18 km this is a long effort, so pacing discipline matters more than raw power. Anchor your target to a percentage of FTP that you can genuinely hold for the better part of an hour or more, not a number you can only touch for minutes. If you are unsure of your threshold, run the numbers through the FTP estimator before you commit to a plan. On a 7.83% average, most riders will spend the whole climb near or just under threshold — so start conservatively on the lower slopes and keep a reserve for the 22.54% ramp, where cadence collapses and power spikes whether you want it to or not. Above 2000 m, expect your sustainable output to drop, so bank nothing on the early kilometres.

Gearing

Gear for the steep pitches, not the average. On a climb with a 22.54% maximum and a 7.83% mean sustained for 18 km, running out of cassette is the classic mistake. A compact 34-tooth chainring paired with a wide-range cassette is the sensible baseline: 34×32 will get most fit riders up the sustained sections, but on the 22.54% ramp — especially with fatigue and altitude — a 34×34 gives you the extra room to keep spinning rather than grinding to a standstill. If your frame and derailleur can accept even more range, take it; nobody has ever regretted an easier gear on a hors catégorie wall.

Summary

Coll de l'Aubaga is a proper HC test: long, high, and steep enough to punish poor pacing. Respect the 22.54% pitch, gear generously, and meter your effort against threshold from the very first kilometre.

Length: 18 km
Average gradient: 7.83%
Max gradient: 22.54%
Start: 767 m
Summit: 2179 m
Net gain: 1412 m
Total ascent: 1401 m
Category: HC