Key takeaways
- Active protection has moving parts — spring-loaded camming devices ('cams') that expand into a crack.
- A downward load is converted into outward gripping force against the crack walls.
- It works in parallel-sided cracks and a range of widths, and places quickly.
- Trade-offs: more expensive, heavier, and has moving parts needing care, vs passive pro.
This is general educational information, not instruction. Placing protection is life-critical — learn it hands-on with qualified instruction.
What active protection is
Active protection is climbing protection with moving parts — primarily spring-loaded camming devices (SLCDs, or ‘cams‘) — that hold a fall by expanding against the walls of a crack, converting downward load into outward gripping force.
How cams work
A cam has several spring-loaded lobes on an axle. You retract them with a trigger, slot the cam into the crack, and release so the lobes spring out against the walls. The lobe geometry means a downward pull makes the lobes try to expand outward — so the harder you pull, the harder it grips, letting it hold in parallel-sided cracks where a wedge couldn’t.
Facing a smooth, parallel-sided crack with no constrictions, a trad climber pulls the trigger on a cam, slots it in, and releases — the lobes spring against both walls, and a quick visual check confirms it’s well within its range before they climb on.
Advantages and trade-offs
Advantages: cams work in parallel cracks and across a range of widths (each covers a span of sizes) and place fast — huge on pumpy climbing. Trade-offs: more expensive and heavier than passive protection, with moving parts that can wear, jam, or ‘walk’ deeper, and they need correct sizing. Most climbers carry both cams (including micro-cams) and passive pro.
The bottom line
Active protection means camming devices — spring-loaded lobes that expand to grip a crack, turning a downward fall into outward gripping force, so the harder you pull the harder it holds. Cams work in parallel cracks and a range of widths and place fast, making them a trad cornerstone. They cost more, weigh more, and have moving parts to mind — so climbers pair them with passive pro.
Frequently asked questions
What is active protection?
Active protection is climbing protection that has moving parts — primarily spring-loaded camming devices (SLCDs, or 'cams'). You pull a trigger to retract the cam lobes, place the device in a crack, and release it so the spring-loaded lobes expand to grip the crack walls. It 'actively' grips, as opposed to passive protection that simply wedges in place.
How do camming devices work?
A cam has several spring-loaded lobes on an axle. You retract them with a trigger, slot the cam into the crack, and let go so the lobes spring out against the walls. The lobe geometry means that a downward pull (like a fall) makes the lobes try to rotate and expand outward, increasing the gripping force against the rock — so the harder you pull, the harder it grips. This lets it hold in parallel-sided cracks where a wedge couldn't.
What are the advantages and trade-offs of active protection?
Advantages: cams work in parallel-sided cracks and across a range of widths (each cam covers a span of sizes), and they're fast to place, which is a big deal on hard or pumpy climbing. Trade-offs: they're more expensive and heavier than passive pro, have moving parts that can wear, jam, or 'walk' deeper into a crack, and require correct sizing and placement. Most trad climbers carry both cams and passive pro.
Sources
- Trad protection — American Alpine Club
- Protection & placements — The Mountaineers