Idoia

Overview

Idoia is a short, honest climb that rewards steady effort over heroics. Over 3.8 km it averages 5.1%, lifting you from a start elevation of 115 m to a summit at 310 m. That works out to a net elevation gain of 195 m, with a recorded total ascent of 185 m once the small undulations are smoothed out. As a category-4 ascent, it sits at the gentler end of the classification scale — HC is the hardest, followed by 1, 2, 3, and finally 4 — but the 8.54% maximum gradient means it still has a sting worth respecting.

How the Gradient Unfolds

The defining number here is the gap between the 5.1% average and the 8.54% max. A climb this length that averages just over 5% but peaks near 8.5% is not perfectly even — there is a meaningful spread between the easy and hard sections. Expect stretches sitting comfortably below the average where you can settle into rhythm, punctuated by a steeper pinch approaching that 8.54% figure. The difference between total ascent (185 m) and net gain (195 m) is small, only 10 m, which tells you the profile is essentially one clean upward push rather than a roller with false flats or descents. In practice, you climb, and you keep climbing, all the way to 310 m.

Pacing Notes

Because Idoia is only 3.8 km, the temptation is to attack from the base. Resist it. Anchor your effort to your FTP and aim to hold a controlled, sustainable power through the shallower opening so you have headroom left when the gradient tips toward 8.54%. On a category-4 climb at 5.1% average, most riders can hold slightly above threshold if they meter the steep section rather than being surprised by it. If you are unsure where your threshold sits, run the numbers through the FTP estimator before you plan your pacing, then treat the steepest pinch as the one place you are allowed to briefly go over.

Gearing

For a climb averaging 5.1% and peaking at 8.54%, a compact setup is more than enough for most riders. A 34×32 lowest gear will carry you comfortably through the bulk of the 3.8 km, keeping cadence high on the shallower gradients. If you prefer to spin rather than grind — or you are carrying fatigue, gear, or simply want insurance for the steep 8.54% ramp — dropping to a 34×34 gives you a touch more breathing room without costing you anything on the easier pitches. Neither will leave you undergeared on a category-4 ascent of this profile; choose based on how fresh your legs feel.

Summary

Idoia is a quick, well-mannered climb: short enough to attack, steep enough in one spot to punish a bad pace. Meter your effort, respect the 8.54% pinch, and you will crest the 310 m summit with plenty in reserve.

Length: 3.8 km
Average gradient: 5.1%
Max gradient: 8.54%
Start: 115 m
Summit: 310 m
Net gain: 195 m
Total ascent: 185 m
Category: 4