Puerto de Ventana

Overview

Puerto de Ventana is a Category 1 climb in northern Spain, rising 752 m net over 7.8 km at an average gradient of 9.62%. That average alone puts it firmly in the "respect it or suffer" bracket, but the headline number that matters most is the maximum gradient of 23.66% — a wall-gradient pitch that can shatter a poorly paced effort in seconds.

Total ascent across the 7.8 km comes to 1,087 m, which signals the road isn't a clean ramp. Elevation gain and loss are stacked throughout, meaning you pay for every flat or false-flat section twice: once in the legs, once in the rhythm when the gradient kicks back up.

How the Gradient Unfolds

With a 9.62% average sustained across under 8 km, there is no extended recovery on this climb. The gap between average gradient and maximum gradient — nearly 14 percentage points — tells you the profile is irregular. Expect stretches that are manageable at 7–8%, punctuated by ramps that surge into double digits and spike toward the 23.66% maximum.

That near-24% pitch is not a rounding error. At that angle, forward momentum collapses rapidly if power output drops, and traction on the rear wheel becomes a real concern in wet conditions — common in Asturian mountains.

Key Gradient Phases

• Lower slopes: Starting at 823 m, the road begins the work early. There is no flat runway to settle in.
• Mid-climb surges: The difference between net gain (752 m) and total ascent (1,087 m) confirms the road loses and regains height more than once. These undulations break rhythm and inflate cumulative fatigue.
• Maximum ramp: The 23.66% section will arrive when your legs are already loaded. Treat it as a technical obstacle, not a sprint.

Pacing Strategy

An average gradient of 9.62% over 7.8 km means you are deep into threshold and beyond territory for the full duration if you push at race pace. For most riders, this climb runs 30–50 minutes depending on fitness — long enough that early aggression is almost always punished.

Start conservative. The temptation on the lower slopes is to use perceived ease as a license to surge. Resist it. Lock into a sustainable effort — ideally 10–15 W below threshold — and preserve capacity for the steep ramps.

At the maximum ramp: Shift down before you need to, not during. On a 23.66% pitch, attempting a gear change under load risks a chain drop or a stall. If you are estimating your FTP ahead of a target ride here, factor in that this pitch will require well above threshold power for even a brief duration.

On the false flats and short descents: Resist the urge to soft-pedal completely. Use them to recover at active effort rather than coasting, so momentum carries you into the next ramp without a dead-leg restart.

Gearing Notes

With ramps approaching 23.66%, a compact chainset (50/34) paired with an 11-32 or wider cassette is the practical minimum for most riders. A mid-compact (52/36) with a 34-tooth sprocket can work for strong climbers, but leaves little margin on the steepest sections. Riders on standard double setups (53/39) should treat this climb with serious caution unless they have exceptional climbing power.

Tyre pressure worth considering: lower pressures improve traction on steep, damp tarmac common in this region. Somewhere in the 70–80 psi range on 25–28 mm tyres is a reasonable starting point.

Bottom Line

Puerto de Ventana is a legitimate Category 1 climb that earns the rating through relentless gradient rather than pure length. At 7.8 km and 9.62% average, with a 23.66% maximum lurking inside, it rewards riders who pace conservatively, gear appropriately, and treat the irregular profile as a series of micro-efforts rather than one sustained push.