CMI Foot Ascender

The CMI foot ascender mounts to your boot and grabs the rope each time you step, so climbing a single rope feels closer to walking up stairs than pulling yourself up. For climbers who ascend SRT into big trees, a foot ascender is often the biggest energy saver in the system.

Why use a foot ascender

Single rope ascent is mostly about how efficiently you turn leg strength into height. With a foot ascender on one boot, every step grabs the rope and holds your gain, while your hitch or device slides up behind it. It also keeps the rope tensioned below you, so your upper system feeds smoothly without a hand dedicated to pulling slack.

Climbers who ascend 60 or 80 feet into a big tree several times a day notice the difference fast. Less arm work on the way up means more energy for the actual job: rigging, cutting and moving through the canopy.

It also helps when you change direction in the tree. Because the foot ascender keeps tension on the rope below you, your device or hitch moves more cleanly, and you spend less time fiddling with slack and more time getting to work position. Over a full day of foot ascenders and multiple climbs, the savings in arm strength are obvious.

Setting it up

Most climbers wear the foot ascender on one foot and a foot loop or knee ascender on the other side, combined with a chest-mounted device or hitch on the saddle. The exact setup depends on your system, and you should match it to what you have been trained on. Strap it securely to a stiff-soled boot so it does not roll off when you step.

Check the rope diameter range and compatibility in CMI's instructions before using it on your line. Practice low to the ground until the stepping rhythm feels natural and the release is second nature, especially for the moment you transition from ascent to work position.

Before you leave the ground, check how the rope runs from your upper device past the foot ascender. Twists in the line or a strap that rides up your boot will make each step awkward. A few practice steps low down sort that out quickly.

When you reach your tie-in, many climbers flip the foot ascender off the rope so it does not catch on branches while they work. Get comfortable doing that with gloves on.

Safety and inspection

A foot ascender is an ascent aid, not your life support. You must always be connected to your saddle through your primary system, and that system must meet the applicable standard and be used per ANSI Z133 and the manufacturer's instructions. Get training before you add any mechanical ascender to your climbing.

Inspect before each use for wear on the cam teeth, cracks, a weak spring, and frayed or cut straps. Clean out grit and sap, which can stop the cam from biting. Retire it if you see damage. Pair it with an arborist foot loop or a knee ascender for a full rope walking setup.