Paso del Planchón

Overview

Paso del Planchón is a long, high-altitude category 1 climb that rewards patience over aggression. Over 28.5 km it lifts you from a start elevation of 1103 m to a summit of 2514 m, a net gain of 1411 m. Because the road pitches and dips along the way, the total ascent adds up to 1431 m — slightly more than the net figure, a reminder that not every metre climbed stays climbed. The average gradient of 4.95% sounds gentle, and for long stretches it is, but a maximum of 18.51% lurks somewhere in the profile to break any rhythm you thought you'd found.

How the Gradient Unfolds

Treat that 4.95% average with suspicion. On a climb this long, the mean is a blend of easy false-flats and much steeper ramps, and the 18.51% max tells you the hardest section is roughly three to four times steeper than the average. Expect the grade to breathe: shallow, spinnable kilometres where you can settle into a cadence, punctuated by sharper kicks that force you out of the saddle. The gap between the 1411 m net gain and the 1431 m total ascent — 20 m of extra climbing — comes from those small descents that interrupt the ascent and cost you momentum each time the road tilts back up. At altitude, near the 2514 m summit, thinner air makes even moderate grades feel harsher than the numbers suggest.

Pacing Notes

The single most useful discipline here is restraint. At 28.5 km, this is an effort measured in tens of minutes, not seconds, so anchor your intensity to your FTP rather than to how fresh you feel in the first few kilometres. Riding just below threshold on the shallower sections banks the energy you'll need for the 18.51% ramp, which will spike your power well above sustainable output no matter how you meter it. If you're unsure of your number, run the FTP estimator before you go, then hold a touch under it for the bulk of the climb. The last kilometres above 2000 m are where the altitude taxes you most — leave a reserve for them.

Gearing

Gear for the steep ramp, not the average. A 4.95% mean is comfortable on almost anything, but the 18.51% maximum near the top of a 1411 m climb is where undergeared riders grind to a halt. A compact 34-tooth chainring paired with a 34×32 low gear is the sensible baseline for most riders on a climb of this length. If you climb at a lower cadence, carry extra weight, or simply want insurance against that 18.51% wall arriving after 1400 m of accumulated fatigue, step up to 34×34. The wider range costs you nothing on the flatter sections and buys you a spinnable escape hatch when the grade bites.

Summary

Paso del Planchón is a climb of endurance and management: long enough to demand pacing, high enough to demand respect for altitude, and steep enough in one spot to demand real gearing. Ride it to its rhythm and the 2514 m summit is a genuine achievement.

Length: 28.5 km
Average gradient: 4.95%
Max gradient: 18.51%
Start: 1103 m
Summit: 2514 m
Net gain: 1411 m
Total ascent: 1431 m
Category: 1