collado de Tancalaporta

Overview

Collado de Tancalaporta is a hors catégorie monster, the kind of ascent that reshapes an entire day on the bike. Over 25.5 km it climbs from 835 m at the base to a summit of 2334 m, a net gain of 1499 m. The average gradient reads a deceptively civil 5.87%, but that single figure hides everything that makes this climb famous — including pitches that spike to a leg-breaking 31.18%. With a total ascent of 1496 m packed into its length, this is a sustained, high-altitude effort that rewards patience and punishes ego.

How the Gradient Unfolds

The story of Tancalaporta is written in the gap between its average and its extremes. A 5.87% mean across 25.5 km sounds like a rhythm climb, and for long stretches it behaves like one — steady enough to settle into a cadence and grind. But the 31.18% max gradient tells you the road refuses to stay polite. Expect the profile to lurch: mellow drags where you can recover, then abrupt ramps that force you out of the saddle and strip your momentum in a few metres. Because the net gain (1499 m) sits just above the total ascent (1496 m), there is almost no false flat or descent to break the effort — nearly every metre of this climb goes up. That relentlessness, more than any single ramp, is what defines the 2334 m haul to the top.

Pacing Notes

Treat the average, not the max, as your anchor. On a climb this long, the winning move is discipline: hold a sustainable effort just under threshold and save reserves for the steep spikes rather than burning matches early. Anchor your intensity to your FTP — a climb of 25.5 km is far too long to spend above it. If you don't know your number, run the FTP estimator before you commit to a pacing plan. When the road tilts toward that 31.18% wall, let cadence drop and power surge briefly, then settle straight back to your target once the gradient eases. Fuel early and often; 1499 m of climbing is a long time to stay fed and hydrated, and bonking at altitude near 2334 m turns a hard day into a survival march.

Gearing

Gear for the spikes, not the average. A 5.87% mean is manageable on almost anything, but a 31.18% ramp demands the lowest gearing you can reasonably fit. A compact 34-tooth chainring is the sensible front, and you'll want as much cassette as you can get behind it. A 34×32 is the practical minimum here — enough to survive the steep pitches while keeping your legs turning. If your frame and derailleur allow it, go further to a 34×34; the extra tooth buys precious cadence on the very steepest sections and protects your knees across 25.5 km of continuous effort. On an HC climb, easier gearing is almost never a mistake.

Summary

Collado de Tancalaporta is a full HC test: long, high, and studded with gradients steep enough to end your climb if you arrive under-geared or over-cooked. Respect the length, pace to your threshold, gear low, and eat before you're hungry — and 25.5 km later you'll crest at 2334 m having earned every metre.

Length: 25.5 km
Average gradient: 5.87%
Max gradient: 31.18%
Start: 835 m
Summit: 2334 m
Net gain: 1499 m
Total ascent: 1496 m
Category: HC