Col de Portet d'Aspet

Overview

Col de Portet d'Aspet sits in the French Pyrenees and carries a Category 2 rating. On paper, its numbers look manageable: 11.5 km at an average gradient of 4.67%, rising 535 m from a start elevation of 538 m to a summit of 1,073 m. In practice, that average masks one of the most violent gradient spikes you will encounter on a categorised climb anywhere — a maximum of 44.48%.

That figure is not a typo. It demands specific preparation and honest pacing.

How the Gradient Unfolds

The total ascent logged across the 11.5 km is 1,304 m — considerably more than the straight-line elevation difference of 535 m. That discrepancy tells you the road is not a steady ramp. Expect genuine undulations, short recoveries, and then abrupt ramps that more than account for the extra vertical.

The average of 4.67% sits in a range that feels comfortable at endurance pace for much of the lower slopes. Use those sections deliberately. The climb rewards athletes who treat the gentler stretches as active recovery rather than an opportunity to push tempo.

The maximum gradient of 44.48% is a wall-gradient number. Sections approaching that figure require either a very low gear ratio or the ability to ride extremely slowly without losing balance and momentum. On a road bike with a standard compact chainset, even a 34×32 combination will feel taxing. On a climb with this kind of spike, knowing your FTP and your sustainable power at very low cadence is not optional — it is the difference between riding through the ramp and walking it.

Pacing Notes

• Bottom third: The road rises from 538 m. Resist any temptation to attack early. The total ascent figure of 1,304 m tells you there is more climbing in the legs of this route than the summit elevation alone suggests.
• Middle section: Hold a pace you can sustain through the steepest pitches. If you are already at threshold here, the ramps will crack you.
• The steep pitches: When the gradient kicks toward its upper range, shift to your lowest gear before you need it. Trying to change under maximum load risks a dropped chain or a stall.
• Cadence management: On ramps that approach the maximum, a higher cadence becomes impossible. Grinding at 50–60 rpm is acceptable; coming to a near stop because you ran out of gear is not.

Gear Recommendations

For a climb with a reported maximum of 44.48%, standard compact gearing (50/34 chainring, 11-28 cassette) is insufficient on the hardest pitches. A 34-tooth chainring paired with a 32- or 34-tooth sprocket is the minimum sensible setup. Riders on 1x drivetrains should ensure their cassette extends to at least 36 teeth.

Gravel and touring setups with sub-1:1 ratios will handle the extreme ramps more cleanly than road-specific equipment.

Practical Summary

The Col de Portet d'Aspet cycling climb is not the longest or the highest Category 2 in the Pyrenees, but the maximum gradient places it in a different conversation from most. Treat the benign average with suspicion, gear accordingly, and conserve enough in reserve to survive the sections where the road pitches into double-digit gradients and beyond.