Cir pass

Overview

Cir pass is a genuine high-mountain effort: 36.7 km of continuous climbing that lifts you from 545 m at the base to a summit of 2456 m. That is 1911 m of net elevation gain, backed by 1886 m of total ascent — meaning the road climbs almost without relief, giving back only a handful of metres along the way. The average gradient of 5.21% sounds friendly on paper, but averages lie on a climb this long. This is a hors catégorie (HC) ascent, the hardest classification going, and it earns that label through sheer duration rather than relentless steepness.

How the Gradient Unfolds

The number that reshapes everything is the max gradient of 27.79%. A wall that severe cannot be sustained for long, so it hides inside the profile as a short, brutal ramp rather than a defining wall. Around it, the 5.21% average tells you the climb spends most of its length in a moderate, grindable range — the kind of grade you can turn over for hours, punctuated by steeper kickers.

Think of Cir pass in thirds. The lower and middle sections do the heavy lifting of the 1911 m gain, likely settling into steady mid-single-digit percentages. The sting is the variance: with a peak of 27.79% against an average barely above 5%, the road clearly swings hard between shallow and severe. Those spikes are where fresh legs stay calm and tired legs unravel.

Pacing Notes

At 36.7 km, Cir pass is an exercise in restraint. The single biggest mistake here is treating the early, gentler slopes as an invitation to push — you have well over an hour of climbing ahead, and every match burned low costs double up high where the air thins toward 2456 m.

Anchor your effort to your FTP. On a climb of this length, holding a touch below threshold keeps you sustainable through the full 1911 m of gain, with headroom left for the 27.79% pitch that will briefly spike your power far above target. Let those ramps come, ride them seated where you can, and drift back to your steady number the moment the road eases.

If you are unsure of your threshold, run the numbers first with the FTP estimator and set a realistic ceiling before you start. Discipline over the opening third is what gets you to the summit with something left.

Gearing

Bring climbing gears. On a 36.7 km HC ascent topping out at 2456 m, low ratios are not a weakness — they are how you protect your legs across hours of ascending. A compact 34-tooth chainring paired with a wide cassette is the sensible baseline.

A 34×32 will cover most of the steady 5.21% terrain comfortably. But given the 27.79% max pitch, go one step further: a 34×34 gives you the extra spin to survive that ramp without grinding to a crawl or blowing past your target power. If your bike accepts it, the 34×34 is the safer choice for keeping cadence over such a long, high climb.

Summary

Cir pass is a duration climb first and a steepness climb second: 36.7 km, 1911 m of net gain, and a summit at 2456 m demand patient pacing and generous gearing far more than raw power. Respect the length, mind the 27.79% spike, and let the 5.21% average do its slow work.

Length: 36.7 km
Average gradient: 5.21%
Max gradient: 27.79%
Start: 545 m
Summit: 2456 m
Net gain: 1911 m
Total ascent: 1886 m
Category: HC