Col du Grand Mottay

Overview

The Col du Grand Mottay is one of those climbs that reads like a typo. At 8.9 km with an average gradient of 14.25%, it sits firmly in the hors catégorie bracket — the hardest rating there is, above categories 1, 2, 3 and 4. From a start elevation of 380 m it hauls you to a summit of 1653 m, a net elevation gain of 1273 m over its total ascent of 1215 m. There is no easing into this one. The moment the road tilts up, it commits, and it expects you to commit too.

How the Gradient Unfolds

A 14.25% average across 8.9 km is not a number that hides anywhere gentle. Even without a listed maximum gradient, the arithmetic tells the story: to average 14.25% over the full 8.9 km, the road has to hold ferociously steep pitches for kilometre after kilometre. Gaining 1273 m of net elevation across such a short distance leaves no room for flat recovery or false descents — every metre forward is a metre spent fighting gravity. Expect the climb to feel front-loaded in effort simply because you never get the relief of a shallow ramp to reset your legs. The shape here is less a staircase and more a single, unbroken wall from 380 m to 1653 m.

Pacing Notes

On a climb this steep, pacing is survival. Because the gradient rarely dips, your power will spike hard the instant you push, so the goal is to hold a sustainable effort just under threshold rather than chasing a rhythm you cannot keep. Riders who know their FTP should plan to sit at or slightly below it for the full 8.9 km — surges on a 14.25% pitch cost far more than they return. If you are unsure of your number, run it through the FTP estimator before you go, then work out the wattage you can hold for the roughly climb-length duration. With 1273 m of gain to absorb, the smart move is to start conservatively and only lift the effort once the summit at 1653 m is genuinely in reach.

Gearing

Do not under-gear this. A 14.25% average sustained over 8.9 km will overwhelm a road-standard setup for most riders. A compact 34-tooth chainring paired with a wide cassette is the minimum sensible choice — a 34×32 will get many strong climbers up, but on gradients this relentless a 34×34 gives you the extra breathing room to spin rather than grind. If your legs or your terrain leave any doubt, err toward the easier ratio; grinding a big gear for 1273 m of climbing is how you blow up before the summit. Cadence protects your legs here far more than raw strength does.

Summary

The Col du Grand Mottay is a pure test of steepness and stubbornness: short in distance, savage in gradient, and unforgiving from base to top. Gear low, pace with discipline, and respect the wall.

Length: 8.9 km
Average gradient: 14.25%
Max gradient: n/a
Start: 380 m
Summit: 1653 m
Net gain: 1273 m
Total ascent: 1215 m
Category: HC