Puerto de Zaldiaran

Overview

Puerto de Zaldiaran is a short, honest category 4 climb — the kind of ascent that rewards a smooth tempo rather than heroics. Over 3.8 km the road lifts you from 512 m at the base to 687 m at the top, a net gain of 175 m. The average gradient of 4.62% keeps things firmly in aerobic territory, and even the steepest ramp tops out at just 6.41%. There are no wall-like pitches here, no sudden double-digit surprises. What you get instead is a consistent, rolling grind that suits riders who like to settle into a rhythm and hold it.

How the Gradient Unfolds

With an average of 4.62% and a maximum of only 6.41%, this is one of the more uniform climbs you will find. The gap between the mean and the peak is under 2% — 1.79% to be exact — which tells you the road rarely strays far from its steady character. Expect the effort to feel remarkably even from bottom to top. The 175 m of net gain is spread across the full 3.8 km, so no single section demands a dramatic gear change. The total ascent of 158 m sits just below the net figure, confirming there is little to no descending or false-flat relief interrupting the climb — you are going up, gently but continuously, the whole way.

Pacing Notes

Because the gradient is so consistent, Zaldiaran is an ideal climb for locking into a target power and never wavering. Aim to ride it just below your FTP if you want to arrive at the summit fresh, or sit right at threshold if you are treating it as a test piece. At 4.62% the pace is high enough that momentum carries you, so avoid surging — small accelerations on a climb this steady cost more than they gain. If you are unsure what your threshold number actually is, run a quick check with the FTP estimator before you plan your effort. On a climb without steep pitches, holding a fixed wattage from base to top is the fastest and most repeatable strategy.

Gearing

You do not need mountain gearing for a climb that never exceeds 6.41%. A compact chainring paired with a mid-range cassette is more than enough. A 34×32 lowest gear gives most riders a comfortable spin at the 4.62% average and leaves headroom for the 6.41% max without grinding. If you tend to climb at a lower cadence, prefer a bit more insurance, or are carrying fatigue from earlier in a ride, a 34×34 offers a slightly easier bailout and lets you keep the legs turning smoothly all the way to 687 m. Either setup will serve you well; the choice comes down to your preferred cadence and how much reserve you like at the bottom of the block.

Summary

Puerto de Zaldiaran is a clean, steady category 4 climb — short enough to attack, uniform enough to pace perfectly. Set your rhythm at the 512 m base, hold it through the 175 m of climbing, and roll over the 687 m summit knowing the road never threw anything harder than 6.41% at you.

Length: 3.8 km
Average gradient: 4.62%
Max gradient: 6.41%
Start: 512 m
Summit: 687 m
Net gain: 175 m
Total ascent: 158 m
Category: 4