The tip comes from @fitzy315 and @climbing.technical, a great Instagram account with lots of rigging tips and nice diagrams.

Progress capture pulleys (aka PCP) , such as Petzl Traxion, have long been crucial gear for big wall hauling. As these PCPs have gotten smaller and lighter, pulleys like the Petzl Micro / Nano Traxion and Edelrid Spoc are becoming standard kit for alpine climbers, especially for crevasse rescue. These devices combine a high-efficiency pulley wheel with a toothed, spring-loaded cam that grabs the rope. This “captures the progress” as you pull, allowing the rope to only move in one direction.

While in theory these are simple to rig, it can be confusing to do it correctly. This can be especially true in the added stress of a rescue situation, or if the pulley is in a different configuration than how you may normally rig it, such as on your harness rather than clipped to an anchor.

To thread it correctly, remember: “Teeth to Tail”.

When threading the rope into the pulley, rig it so the TEETH are resting on the TAIL of the rope, aka the end you're pulling on.

That way, you’ll always capture the progress correctly. Hopefully this is obvious, but the glove indicates where your hand is, which shows the pulling force on the “tail” of the rope.

Note:

• In the photo below, I'm using a very short length of rope to clearly show where the tail is.

• The pulley only has one of the two plates clipped to the carabiner, I left it open so you could see where the teeth are. When using it for real, you have to close the swinging plate and clip both of the holes.

Stamped on the inside of the Nano and Micro are little icons for a “load” and “hand”, which can also be helpful to remind you. Even with this, I still find “teeth to tail” more helpful.

(And if you gearheads are wondering, yes, that is the black ninja version of the new Petzl Nano Traxion. A very nice piece of gear!)