Col de l'Arzelier

Overview

Col de l'Arzelier is a Category 1 climb in France, running 10.7 km from a start elevation of 358 m to a summit at 1160 m. That works out to a net elevation gain of 802 m at an average gradient of 7.5%. On paper, it is a classic long alpine effort: steep enough to hurt, long enough that you cannot bluff your way over it on fitness alone.

The number that reframes the climb is total ascent. You gain 802 m net, but the road actually climbs 1117 m from bottom to top. That 315 m gap is undulation — sections where the road dips or flattens and then reclaims the height. It means you are doing more vertical work than the net figure suggests, and every descent you enjoy is height you have to earn back. Plan your effort around 1117 m of climbing, not 802 m.

How the Gradient Unfolds

A 7.5% average hides a lot. On an undulating climb like this, the mean is pulled down by recovery sections, which means the working pitches are steeper than 7.5% to compensate.

• Flatter or descending recovery sections that account for the gap between net gain and total ascent
• Repeated short climbing blocks where the road claws back the height it just gave away
• Steeper ramps well above the average, where the real cost of the climb is paid

Do not let a gentle opening lull you into overspending. The average is an accounting trick; the road is not evenly graded.

Pacing Notes

On an evenly graded climb you can chase even speed. Here you cannot. The undulation makes even-speed pacing a trap — holding a fixed pace up the steep ramps means burning matches you will want back on the next pitch. Pace to even effort instead: let your speed rise on the flatter recovery sections and accept that it will fall on the ramps, keeping your power steady throughout.

Anchor that effort to your sustainable power output and hold a touch below it on the steep sections rather than surging. If you do not know your number, run the FTP estimator before you go, then ride to it.

Gearing

Gearing on this climb is governed by the steepest ramps, not the average. For 10.7 km with steep double-digit pitches, run a compact (50/34) or sub-compact chainset paired with a wide-range cassette — a 34×32 or 34×34 low gear gives you the spin to hold cadence when the road kicks up. Grinding a big gear up the steep sections will cost you the recovery pitches later. Check your setup before the ride: confirm the cassette and derailleur can actually take that low gear, rather than discovering the limit halfway up.

Summary

• Length: 10.7 km
• Average gradient: 7.5%
• Net elevation gain: 802 m
• Total ascent: 1117 m
• Category: 1

Col de l'Arzelier rewards riders who respect the total ascent over the net gain. Pace to even effort, gear low enough for the steep ramps, and treat the recovery sections as part of the climb rather than a rest — and this Category 1 will go a lot smoother.