A Teton rappel. On this particular day I used the Grivel Scream with a Sterling V-TX 5.4mm rope. Thankfully we had enough rope to avoid a single stranded rappel here. Photo: Adam Fabrikant
As high tech, skinny ropes continue to grow in popularity throughout the ski touring world, I often wonder how many users are having close calls or scary experiences rappelling on these ropes. In many ways, rappelling on a 6mm-ish rope is similar or the same process as rappelling on a regular climbing rope—but when it comes to adding friction, the skinny ropes require some practice, personal testing, and expertise.
When we think of rappelling techniques, the most basic requirement is adding sufficient friction to descend the rope in a controlled manner but not so much friction that we can’t descend easily. The original, and most basic friction device is your body, as exemplified by the Dülfersitz or an arm rappel (wrapping the rope around your wrists/forearms and across your back). Fortunately, for our comfort and safety, brands have progressed to various friction devices designed for belaying and rappelling. The most ubiquitous modern devices are tube styles like an ATC, or Petzl Reverso—these devices simply attach the climber to the rope while introducing a sufficient amount of friction for a controlled descent.
Duelfersitz Rappel, no gear needed. Photo: Wulf Alex Link to copyright
When it comes to skinny ropes around 6mm, you will quickly realize that a standard ATC or Reverso does not provide nearly enough friction for a controlled descent, and often makes for a disconcerting or downright dangerous rappelling experience. While there are ways to make these devices work (stay tuned), there is a growing supply of devices made with these skinny ropes in mind—we will cover many of these options below.
Rappel devices in question from the top left going clockwise: Grivel Scream, Edelrid Mago 8, BD ATC Alpine Guide, Edelrid MicroJul.
For several reasons, I set up each device with an extension and a “third-hand” backup. This setup is worthy of its own post, but in brief, the extension helps add friction, allows for a full-strength backup off the belay loop, and allows me to go hands-free to untangle ropes or check anchors. I’ve been using a 110cm Blue Ice alpine runner as a tether and extension, or if I’m doing many rappels or in a group larger than two, I bring a Petzl Connect to adjust for added tether adjustability.
My current preferred tether/extension setup—using a 110cm Blue Ice alpine runner. Easy to untie, robust, and sleek.
Devices
BD ATC Alpine Guide
This is a great starting point for most people with most ropes. The ATC Alpine works like a standard ATC style device, so it requires minimal adjustment from a full-size device to work pretty well with skinny ropes. The recommended range is 6.9-8.5mm, so 6mm ropes fall outside the recommended range. That noted, as a double rope rappel with the Beal Backup line, the friction is sufficient with most carabiners. With some tomfoolery (see the Reverso section below), sufficient friction can be achieved with slick ropes or a single strand. Still, in a standard setup, a single strand rappel on any of the common skinny lines is a terrible option.
Standard setup of the Black Diamond ATC Alpine Guide.
The shrunken slots on the ATC Alpine Guide provide significantly better friction with small ropes.
BD ATC Alpine Guide - 74.1g
Grivel Scream
This is a mini version of a plate style device like the Kong GiGi. While it is one of few devices explicitly recommended for sub 6mm ropes, the plate design is generally suboptimal for rappelling. It requires an extra carabiner compared to the other options, and the setup is a bit more complex and easier to get wrong relative to an ATC style device. I was excited about the Scream when it first came out, but I rarely reach for it these days. A few orientations are possible with the Scream, although the friction adjustments they provide are minimal. Every rappel I’ve done on the Scream leaves a small collection of rope sheath along the slots in the device, which can’t be good for rope longevity. Overall, While I appreciate Grivel making a device for these ropes, I’m not sure the plate style is ideal for this application. Recommended for 5-8mm ropes.
Grivel Scream in what I believe is the highest friction setup. Needing two carabiners feels heavy and clunky in this context.
The other side of the Grivel Scream, note how the rope runs over the orange carabiner - careful of burrs on the gate pin!
Grivel Scream, 44.1g. Requires two locking carabiners for normal use so add ~40g.
Edelrid Micro Jul
The Micro Jul seemed like an amazing device when I first found/purchased it 5-6 years ago. Fast forward, and it’s been 5-6 years since it left my gear closet. It’s a bit confusing to use; the auto-locking mode seems like a great idea, but feeding rope on low-angle rappels is often challenging. Flipping the device such that the rope feeds in from the back is possible, effectively eliminating the auto lock function. This orientation leaves you without a functional wire loop for loss prevention. Overall, I just haven’t found this thing better than an ATC alpine in any of the day to day tasks of winter ski mountaineering/rappelling. Recommended for 6.9-8.9mm ropes.
Edelrid Micro Jul, note that in a normal context, a third hand isn't necessary as the Micro Jul auto locks quite well.
The Edelrid MicroJul. Note the thumb loop, camming this loop upwards opens the device to allow descent. This can be quite a bicep workout on a low angle rappel.
Edelrid MicroJul - 62.1g. The body of the device is steel, so if you like to use the device, it'll last you a while. Mine will last an eternity given my distaste for it.
Edelrid Mago 8
I just bought myself a Mago 8, so these impressions are gleaned from yard fooling rather than the “real” world. That said, this little device has a ton going on and seems to meet all the eventualities/possible needs for ski mountaineering in the lower 48. It has many friction options for rappelling—it seems likely that it would be possible to add enough friction for a single strand of 6mm cord. The Mago also has a belay plate functionality for bringing up a second or rappelling in plate mode, similar to the Grivel Scream. In my off-the-deck tests, it was easy to add/subtract wraps on the “horns” to increase/decrease friction. I got good friction/control on a single strand of Petzl Pur’line, the slipperiest of the ropes I own. Adding to my excitement with this device, it only requires one carabiner, and the rope doesn’t run through the said carabiner, so a superlight locker such as the Grivel Plume is the obvious choice. Recommended for 6-9.5mm ropes.
The "standard" setup of the Edelrid Mago 8.
Edelrid Mago 8 with an additional wrap for added friction with a slick single strand of Petzl Pur'line.
Edelrid Mago 8, 38.2g. Keep in mind, one can use a single, superlight locking carabiner with this device as well.
Petzl Reverso Hacks
Maybe skinny rope rappels are an infrequent activity, or you just don’t want to own another piece of equipment for this specific task (I can’t relate). A good old fashioned Reverso (or BD ATC, DMM Pivot, etc.) can be “hacked” to provide suitable friction with many skinny ropes in a two strand rappel. There are many ways people have rigged this over the years, some better than others. Here are a few we like:
A clever and high friction Reverso threading method I picked up from Mark Smiley. Both ropes in both slots!
Another view of the "both ropes both slots" method, I would worry a bit about odd wear patterns on the middle rib of the device if I was using this all the time.
Two ropes in one slot on the Petzl Reverso, a handy trick.
A snug fit makes for good friction.
Conclusion
I’m not sure the perfect device for these applications exists yet. For most circumstances, the ATC Alpine or Mago 8 seem to make a lot of sense, but the ATC Alpine falls short in the case of a single strand rappel on many of these ropes—which I view as a worst case scenario as far as rappelling friction/security, but also a possible necessity in a pinch.
Perhaps, the perfect device was out there in the form of the Petzl Reversino, a discontinued mini device that many folks have hoarded and swear by. We will explore rope options, different tether/extension setups and more as we delve into the nuance of these systems. Let us know if there are any devices or tricks we are missing, or other lessons to share on the topic of rappelling on skinny ropes.
