Alto de Iso

Overview

Alto de Iso is a compact category 4 climb that packs its work into a tidy 2.7 km. Over that distance it averages 5.49%, lifting you from a start elevation of 507 m to a summit at 655 m — a net elevation gain of 148 m. The recorded total ascent is a touch lower at 131 m, which tells you the road is not relentlessly upward but rolls slightly on its way to the top. With a max gradient of 6.59%, nothing here is savage; this is a climb defined by steadiness rather than shock.

Category 4 is the gentlest rung on the classification ladder (below 3, 2, 1 and the hors catégorie monsters), and Iso wears that label honestly. It rewards rhythm over heroics.

How the Gradient Unfolds

The numbers describe a remarkably even climb. An average of 5.49% sitting just under a max of 6.59% means the gradient rarely strays far from its mean — the gap between typical and peak is only about 1.1%. There are no walls, no double-digit ramps waiting to break your cadence.

The difference between the 148 m net gain and the 131 m of total ascent hints at a short false-flat or brief easing somewhere along the 2.7 km, a spot where you can recover a few beats before the road tilts back to its working grade. Expect to spend most of the climb in a single sustainable effort, tapping out watts at a near-constant pitch from bottom to top.

Pacing Notes

Because the gradient is so consistent, Iso is an ideal climb for pacing by feel or by power. Hold an effort just below your FTP and you can carry it the full 2.7 km without blowing up — the climb is too short to punish a slightly ambitious start, but long enough to reward a smooth, controlled tempo.

If you are not sure where your threshold sits, run the numbers through the FTP estimator before you plan an attack. On a 148 m ascent, going out 10 to 20 watts too hot in the first minute is the only real way to make this easy climb feel hard. Settle in early, breathe evenly, and let the even grade do the work.

Gearing

For most riders a standard compact setup is more than enough here. A 34×32 lowest gear gives you comfortable headroom on a 5.49% average and keeps your cadence spinning even at the 6.59% pinch points. If you prefer to sit and turn a lighter gear — or you are carrying fatigue from a longer day — a 34×34 adds a little more insurance without any downside on a climb this short. Neither will leave you grinding.

Summary

Alto de Iso is a friendly, well-mannered category 4 climb: short, evenly graded, and perfect for dialling in a steady tempo. At 2.7 km averaging 5.49% with a modest max of 6.59%, it asks for rhythm, not raw force.

Length: 2.7 km
Average gradient: 5.49%
Max gradient: 6.59%
Start: 507 m
Summit: 655 m
Net gain: 148 m
Total ascent: 131 m
Category: 4