Kleines Tor - La Portella

Overview

Kleines Tor - La Portella is a hors catégorie climb that gives you nowhere to hide. Over 17.9 km the road averages 8.64%, and it does so while lifting you from a start elevation of 768 m all the way to a 2316 m summit. That is 1548 m of net elevation gain, with 1521 m of total ascent packed into a single sustained effort. There is no valley kicker, no token digit on the sign — this is a climb whose average gradient alone would break most riders, and it holds that average for the better part of an hour or more.

How the Gradient Unfolds

The defining feature here is relentlessness. An 8.64% average across 17.9 km means the climb almost never relaxes: there is very little flat road to recover on, and the small gap between net gain of 1548 m and total ascent of 1521 m tells you the profile barely dips anywhere. You climb, and you keep climbing.

Layered on top of that steady grind are the pitches that push toward the 21.71% maximum. Those ramps are the moments that decide your day — sections where the gradient more than doubles the average and forces you out of rhythm. Between them, the road settles back toward its punishing baseline, but at this altitude, with the summit sitting at 2316 m, the thinning air compounds every steep metre. The last kilometres are as hard as the first because the terrain never rewards you.

Pacing Notes

Discipline wins this climb. With 17.9 km at 8.64% ahead of you, going into the red early is a one-way ticket to a walk. Anchor your effort to your FTP and hold something in reserve for the pitches toward 21.71%, where you will inevitably spike above threshold whether you want to or not.

If you do not know your sustainable number, estimate it first with the FTP estimator, then ride the steady sections a touch below it so the steep ramps do not blow your legs apart. On a climb this long, a metered pace that respects the full 1548 m of gain will beat a fast start every time.

Gearing

Do not underestimate the maximum. A 21.71% pitch at the tail end of 1548 m of climbing demands range. A compact 34-tooth chainring paired with a 34×32 bottom gear is the practical minimum for most riders here, and it will still feel marginal when the gradient bites. If you climb at a lower cadence or carry any fatigue, step up to 34×34 — the extra sprocket buys you spin on the steepest ramps and keeps your effort aerobic rather than muscular. On an HC climb of this length, gearing that is slightly too easy is far safer than gearing that is slightly too hard.

Summary

Kleines Tor - La Portella is a genuine hors catégorie test: long, unrelenting, and steep from bottom to top. Pace it off your threshold, gear for the 21.71% spikes, and treat the full 17.9 km with respect.

Length: 17.9 km
Average gradient: 8.64%
Max gradient: 21.71%
Start: 768 m
Summit: 2316 m
Net gain: 1548 m
Total ascent: 1521 m
Category: HC