by Tree Climbing Instructor Tim "Tengu" Kovar 

A "Tengu Tip" might be an article about a new climbing technique, a note on familiar techniques, news about gear development,

or a tip from other climbers. It could be anything noteworthy that Tim wants to share having to do with climbing trees,

tree climbing gear, or facilitating others into the canopy.

Tip #4: The Yo-Yo Climbing System

(also known as RADS - Rope Ascending Descending System)

April  2007

The Purpose

The Yo-Yo is a safe and efficient style of Single Rope Technique (SRT) climbing. There are several different ways to climb SRT. Most of these methods require one set of equipment to ascend and a separate set of gear to descend. This can be troublesome if an emergency arises, since you have to stop, rig your descender, and de-rig your ascenders, before you can rappel to safety. With the Yo-Yo system, your ascending setup includes your descender, so you are ready to come down as soon as you remove your ascender and foot loop from the system. This eliminates any switching of gear for descent, and you are never accidentally off safety. Yo-Yo is a user-friendly system, especially for the beginner.

The Gear

Gear for the Yo-Yo climbing system is simple. It consists of one ascender with a strap, two locking carabiners, one small pulley like the CMI Micro Pulley, one Petzl Grigri or Petzl I’d descender, twelve feet of accessory cord (9 mm is a good size—ends tied together with a fisherman's knot to create a foot loop), and of course your climbing rope.

For experienced climbers, there is a variation of the Yo-Yo method that uses the ascender without a strap. See Tips below.

The Set-up

Set your rope in the tree for an SRT climb. Once your rope is in place and you have inspected the tree, your rope setting, and thoroughly inspected your gear, you are ready to assemble the Yo-Yo system.


1) Place your ascender on the rope at about eye-level


2) Place a carabiner with the pulley into the bottom hole of the ascender


3) Place the accessory cord foot loop beside the pulley in the same carabiner


4) Place the descender about waist-level on the rope, below the ascender


5) Thread the down rope through the descender, then up and through the pulley


6) Place the ascender strap and the descender on the second carabiner and attach it to your climbing saddle.


The Technique—Ascending

To climb with the Yo-Yo system, pull down on the “down rope” (the end of the rope coming out of the pulley heading towards the ground) until you are on your tiptoes and giving yourself that ultimate wedgie. Sit down in your saddle and adjust the saddle so it feels comfortable. Now place one or both feet into the foot loop, while placing your non-dominant hand into the ascender handle. Grip the down rope with your dominant hand. Slide the ascender up while raising your knee(s), then stand up in the foot loop (use the ascender for balance while standing up), while your other hand is tending slack in the down rope.


You have just gone up the rope a bit. Now SIT back down in your saddle, lifting your knees, and raising the ascender as high as your arm will reach. STAND up, PULL slack, and SIT down. Sit-Stand-Pull, Sit-Stand-Pull. Once you get about fifteen feet into the air you will feel the rhythm of the system. And in no time you will be gliding up the rope.

SIT and raise the ascender

STAND in the foot loop and PULL slack on the down rope


This is the beautiful thing about this system. To descend, all you need to do is release the ascender and engage the descender.


Before detaching the ascender, clip the end of your foot loop to an accessory ring on your harness. Then detach the ascender and let it drop below you. Now engage the descender and you’re on your way down. The rope will run through the pulley without hampering your descent.



• I mentioned before to attach the pulley carabiner to the bottom hole on the ascender. Then if you have to bail out quickly all you need to do is detach the ascender and you are ready to descend. If the pulley carabiner is in the top hole, it’s also around the rope and you will have to detach it first and then detach the ascender before going down. Even in an ideal situation, it can be awkward to de-rig the carabiner from the top hole. Imagine if it were an emergency!


• Most climbing mishaps occur while the climber is on descent. Practice until you are comfortable with descending on your device low to the ground before attempting it at any serious height. To make the Yo-Yo system even safer I recommend that you keep your ascender attached to the rope and use it as a second safety while you descend. Lower your ascender to the descender, descend a couple of feet, then lower the ascender again and repeat the process until you are on the ground. This is slow going, but it will prevent any chance of an uncontrolled descent.

• Experienced climbers rig for Yo-Yo climbing using the ascender without a strap. Climbing this way, the descender is your entire safety connection. Ascending is done as explained above. When you are ready to descend, you can use the foot loop to tether the ascender to your saddle before detaching the ascender from the rope, to prevent accidentally dropping it.

History of the Yo-Yo (RADS) System

There is a lot of controversy over the name of this climbing system. I learned this method over 12 years ago as the Yo-Yo method. This is when Petzl first introduced the Grigri. At that time the Grigri was not recommended as a descending tool, only as a belay device. Bob Waszkiewicz from American Chainsaw, an arborist supply store in Atlanta, received a Grigri to field test for the arboriculture world. After playing with it for a few days he came up with a method for ascending the rope using this device. It was the dawn of a new age in ascending.


I remember him showing us this method without the use of a foot loop or a pulley. The down rope just ran through a carabiner. We all tried it and gave it a thumbs up. Unfortunately we could not teach it to our students because the device was not rated for use as a sole descender.


I do not know the history of the name RADS (Rope Ascending Descending System). I never heard that term until Petzl gave us the stamp of approval that the Grigri was rated as a descender. So in honor of Bob, whose tree climbing name is Yo-Yo, I will continue to name it after him.


If it were up to me, I’d call it the “rope-and-a-half technique.” We have Single Rope Technique (SRT) and Doubled Rope Technique (DRT), but no Rope-and-a-half Technique (R½T). Kinda makes sense, yeah?