Dorah Pass

Overview

Dorah Pass is a hors catégorie climb that gives you almost nothing to hide behind. Over 19.1 km it averages 8.34%, and it does so while sitting entirely in thin, high-altitude air: you start at 2954 m and finish at 4550 m. That is 1596 m of net elevation gain, with 1581 m of total ascent, meaning the road climbs almost continuously with barely a false-flat descent to break the rhythm. Add a max gradient of 18.47% and you have a climb that punishes both fitness and pacing discipline. This is an ascent to respect long before you turn the pedals.

How the Gradient Unfolds

The headline number to internalise is 8.34%. Because net gain (1596 m) and total ascent (1581 m) are nearly identical, there is almost no recovery built into the profile — you go up, and you keep going up. An 8.34% average across 19.1 km is already brutal, but averages lie: with a max of 18.47%, the steepest ramps are more than double the mean. Expect long stretches sitting near or above the average, punctuated by pitches that spike well into the teens. On a climb this consistently steep, the difference between a good day and a blow-up is how much you overspend on those 18.47% ramps rather than the sustained 8-9% grind.

Pacing Notes

Altitude is the second climb hiding inside the first. Finishing at 4550 m means reduced oxygen throughout, so your sustainable power will sag as you climb — pace by feel and breathing, not just by numbers. Anchor your effort to your FTP: on a sustained HC effort this long, most riders target a percentage of FTP they can hold for well over an hour, then trim it further for the thin air up high. If you do not know your threshold, run the numbers through the FTP estimator before you commit to a pacing plan. Start conservatively in the opening kilometres; with 19.1 km at 8.34% ahead, any early over-effort is a debt you repay with interest near 4550 m. Save headroom for the 18.47% ramps and let the sustained sections tick by at a controlled tempo.

Gearing

Gear for survival, not pride. A climb averaging 8.34% with 18.47% spikes at altitude demands a wide, low range so you can spin rather than grind. A compact 34-tooth chainring paired with a 34×32 low gear is the sensible baseline for most riders here. If you run heavier, tire faster at altitude, or simply want insurance for the steepest pitches, a 34×34 is the smarter choice — that extra sprocket keeps your cadence up on the 18.47% sections and protects your legs across the full 19.1 km. Going too tall on a climb this long and this high is the fastest route to a walk.

Summary

Dorah Pass is a complete HC test: length, sustained gradient, punishing ramps, and altitude all stacked into one 19.1 km effort. Pace it early, gear it low, and respect the thin air, and it becomes the kind of climb you remember for years.

Length: 19.1 km
Average gradient: 8.34%
Max gradient: 18.47%
Start: 2954 m
Summit: 4550 m
Net gain: 1596 m
Total ascent: 1581 m
Category: HC