Alto de Pantanillo cycling climb profile
Alto de Pantanillo is short enough to tempt an over-committed start, but steep enough to punish it quickly. The climb runs for 2.8 km, rising from 795 m to 1032 m, with 237 m of net elevation gain. That puts the average gradient at 8.44%, which is the key number here. This is not a long aerobic drag where the gradient slowly wears you down. It is a compact climb where the load is high almost from the moment the road tilts up.
The max gradient is 10.89%, only a little above the average. That matters. It suggests the difficulty is not built around one isolated wall, but around sustained pressure. The hard sections are likely to feel like an intensification of the same problem rather than a completely different challenge. You should not be waiting for the climb to become easy, because the average already tells you the road rarely needs to do much more to create damage.
How the gradient feels
From bottom to summit, the defining feature is density. Over 2.8 km, there is not much time to settle, recover, and reset. The elevation gain comes quickly, and the 8.44% average means each pacing mistake has a short feedback loop. Go too deep early and the summit is still close enough to see as attainable, but far enough away to force a long grind above comfort.
The category 2 classification fits that profile. Alto de Pantanillo is not severe because of distance. It is severe because the climb compresses 237 m of vertical gain into a short effort, with a maximum gradient of 10.89% available to expose riders who arrive over-geared or already above threshold.
Pacing and gearing notes
The right approach is controlled aggression. Start as if the steepest sustained part is still ahead, not as if the top is already paid for. On a climb this short, many riders will try to ride it like a long sprint effort. That can work only if the opening pace is honest and the gearing lets you stay smooth when the road pushes toward the maximum gradient.
Use a climbing gear that lets you keep pressure on the pedals without having to force every stroke. If you are grinding early, you have probably chosen too hard a gear for the profile. The average gradient is already high, so saving one easier gear for the steepest moments is sensible rather than conservative.
For riders using power, this is a climb to anchor around your sustainable climbing effort, then lift only when the summit is genuinely within reach. If you pace by feel, keep the first section just below the point where breathing becomes ragged, then build once the slope has proven there is no hidden recovery. Riders calibrating efforts around /glossary/ftp should treat Pantanillo as a short but demanding threshold-style climb, not a place to chase speed in the opening meters.
Alto de Pantanillo rewards restraint first, then commitment. The numbers make the lesson clear: 2.8 km is brief, but at 8.44% average, the climb is long enough for impatience to become expensive.