The Petzl Tibloc, developed in 1998, was one of the first micro ascenders available. With a simple design, solid steel construction, and sharp teeth that can grab the rope through ice and mud, it remains one of the lightest (35 grams) and most compact emergency ascenders. It’s a handy bit of gear and can be used in some clever ways, some of which may not be very obvious. It can also be a bit finicky unless you know some tricks. Let's take a deeper look at this popular and time-tested piece of gear.

First off, how do you pronounce it? You may have heard several different ways. Petzl USA confirms that it's "tee-bloc", as in “drink some tea”. The original French pronunciation is a truncation of the words "petit bloqueur," meaning "small ascender." (Sweet, glad we got that settled!) The first rope ascender from Petzl (intended for caving) came out in 1968, so they have a very long history of ascender R&D.

How can you use a Tibloc?

• emergency ascender for going up a fixed rope

• the “tractor” pulley in a mechanical advantage hauling system

• progress capture on the anchor

• safeguard the leader when simul-climbing (advanced use only!)

Before we get into the rigging, a few notes . . .

• Around 2018, Petzl introduced Tibloc version 2. In addition to being made from gray steel that offers a better grip, the newer version has a orange plastic hood on it with a small spring. This spring tension gives a much better connection between the carabiner and the rope, regardless of the rope diameter or carabiner shape. (My single greatest grumble with the older version was its tendency to somewhat randomly slide down the rope, which is usually not something you want an ascender to do. See video below). The spring on the Tibloc 2 pretty much eliminates any slipping down the rope, a substantial improvement.

• Avoid taking any kind of a fall with a shock load / slack in the rope onto a Tibloc (or any other toothed ascender.) For example, if you’re ascending a rope, you get to the top of the cliff, and then take a few steps forward without moving the rope through the system, that's generating slack. If you were to fall at this point, you're putting a large force with a toothed ascender onto probably a short amount of rope. No bueno. Avoid this by always minimizing slack rope between you and the anchor.

• The Tibloc is rated for ropes from 8 mm to 11 mm. But, it's also approved for use on the Petzl RAD crevasse rescue system, which uses a special 6 mm static rope. (So, if you need to use it on a slightly smaller rope, you can probably get away with it, but it's not recommended by Petzl.)

• The Tibloc has a bit of a reputation as a rope shredder. In a long-ago crevasse rescue training, I saw firsthand someone put a 1 meter long core shot in an 8 mm dynamic rope as they were putting their (sizeable!) body weight on the Tibloc when ascending. However, most of the time rope damage is probably due to user error, like using the wrong kind of carabiner with an older style Tibloc on a rope that's borderline too small. The Tibloc 2, with the spring-tensioned orange hood, seems substantially more rope-friendly.

• Possible damage to the rope can happen when the carabiner is pressing the rope against the device, and then you try to move it up when it's weighted. Like with most ascenders, try to unweight the Tibloc before you move it.

• It's not for big walls. This is designed for improv and emergency use, If you're jumaring fixed ropes in El Cap or an expedition peak, get a larger handled ascender.

• Petzl recommends always using a locking carabiner with the Tibloc. With the older Tibloc, it’s best if this is a rounded oval or HMS carabiner to avoid damage to your rope and make the Tibloc behave properly. With Tibloc 2, a more modern I-beam style or locking “D” shaped carabiner works fine.

• Speaking of carabiners, the Petzl Sm’D is a great choice to pair with the Tibloc 2. In addition to being a svelte, modern locking D carabiner, it also has a tiny hole, intended for attaching a keeper cord for important bits of hardware like Tiblocs, Micro Traxion, Grigris, etc. See photo below. (This is a much cleaner way to attach a keeper cord then having it flop around the carabiner with a bight knot.)

• Add a keeper cord if you like. There is a small hole in the Tibloc to add one. If you're using it for winter or snow climbing when you might have gloves, make the cord loop fairly large. If rock climbing, you can keep it much smaller. 3 mm climbing cord, or my favorite, bank line (in photo) would be good choices. Some people find the cord is fiddly and gets in the way. It’s entirely optional, so try it and see what you think. See below - the Sm’D carabiner with a clever hole for a keeper cord.

The video below shows a couple of things.

1. The difference between the original Tibloc and version 2. You can see that the original version can slide/fall down the rope if it's not under tension. Not good. No such problem with version 2.

2. You can move the Tibloc down the rope, but it's not very intuitive. You sort of rock the device forward with your index finger and thumb. It's a better show than a tell, watch the video to see how.

Does it damage ropes?

Excellent question! Short answer: it doesn’t damage your rope significantly more or less than other toothed devices, such as Micro Traxion or a handled ascender. Check out the detailed video below from BreakTest Meister Ryan Jenks at HowNot2. Ryan found that the Tibloc destroyed the rope around 6-7 kN.

Some other testing from Richard Delaney at RopeLab show a higher value with an 11 mm static rope of around 10 kN. See that short video here.

Below is a screen grab from the online technical documentation for the Tibloc, showing results that are fairly consistent with what HowNot2 found.

How to clip it (for ascending and as a “tractor”)

There is some discussion as to whether the carabiner should be clipped around the rope (left) or hang straight down from the Tibloc (right). According to Petzl, either way is fine when you’re ascending or using it as a tractor. However if you're using it as a progress capture or to simul climb, it's important that the rope be clipped through the carabiner, as shown below on the left. More on that below.

I got a few comments on social media saying that the rope must ALWAYS be clipped through the carabiner as on the left. Check out the video just above. It was made by rope rigging expert Rich Delaney (who runs the excellent website Ropelab), and you can clearly see that the carabiner is not clipped around the rope.

Petzl’s technical documentation says this is not true; see screen grabs from their website below.

(If you find it easier to remember to always clip the carabiner around the rope, that's great, go for it. But let's not slam on people who use this gear in a different and Petzl-approved way. =^)

Related diagram from Petzl website:

Another diagram from the Petzl website, where the Tibloc is a tractor in a 3:1 haul. The carabiner clipped to the Tibloc is not clipped around the rope.

And finally, here’s a screen grab from a YouTube video produced by Ortovox and the German Mountain and Ski Guides Association (“Verband Deutscher Berg und Skiführer” or “VDBS”). You can clearly see the carabiner is clipping the Tibloc and not the rope. (If some of the top mountain guides in the world say this is how you do it, then I'm gonna roll with that. =^)

Use #1 - As an ascender

For self rescue from a crevasse fall or improvised rope ascending, the Tibloc works great. It’s MUCH easier than the old school prusik! Clip it to the rope with a locking carabiner, add a double runner as a foot loop, and stand up. You can combine this with various devices clipped to your harness to capture your upward progress, such as a Grigri, a plaquette style belay device in guide mode, a progress capture pulley such as a Petzl Micro Traxion (photo below), or even another Tibloc rigged as a progress capture.

A few notes on the photo:

• The blue double length / 120 cm runner is the foot loop.

• Note the single length / 60 cm sling (yellow) from the Tibloc to the harness, plus the Micro Traxion on the harness belay loop. These give you the highly recommended two points of contact to the rope at all times.

• If you want to simplify things a bit, you can omit the yellow sling, but in that case you would want to tie back up knots in the rope below the Micro Traxion every 5 meters or so.

And, since we’re talking Tiblocs, if you happen to have two, you can use a second one on your harness as the progress capture, as seen below. (This is not going to be as smooth or hassle free as the options listed above, but it's possible. Generally, use a Micro Traxion or Grigri if you have one.)

Use #2 - As a “tractor” in a hauling system

In a mechanical advantage hauling system, the “tractor” is the term for the rope grab that’s doing the work. The Tibloc is well-suited for this, and because of its camming action and lack of moving parts, it can bite down and hold on ropes that might be icy or muddy. (If you're not too thrilled with using a toothed cam as a critical component of a hauling system, you can of course use something soft like a prusik loop as the tractor instead.)

Note the orientation of the Tibloc: the orange top is pointed toward the load, not toward of the anchor. (If you set this up wrong, it will become immediately obvious when you pull the rope.) Also in the photo, we have the Micro Traxion progress capturing pulley on the anchor, which is a perfect application for this great piece of gear.

One advantage of the Tibloc if you ever have to pass a knot through your hauling system (such as you might have to do in a two person crevasse rescue scenario with brake knots in the rope) is that it's very fast to remove from the rope and reattach below the knot. (Learn more about dealing with brake knots in crevasse rescue at this article.)

Below is a standard Z drag, which gives a theoretical 3:1 mechanical advantage.

And, if you want to go a little crazy with the Tiblocs, if you happen to have three of them, you can rig a theoretical 6:1 mechanical advantage, as shown below. (If you'd like to learn more about rigging a 6:1, see the Alpinesavvy mechanical advantage pages.) A standard prusik loop can be substituted for either of the two tractor Tiblocs in the photo.

Use #3 - As a progress capture

This is a clever use of the Tibloc that a lot of people don't know about. It grabs the rope with a minimum of friction while maintaining your pulling progress. Rig it so the hole with the keeper cord is in the direction of load. The device will flip back-and-forth over the carabiner sort of like a munter hitch as you change from hauling to resting.

Note: This is best used for emergency or improv (like hauling a backpack) not as a device for sustained hauling of heavy loads like on a big wall. Reason: there are two sources of inefficiency, which is to be avoided whenever possible when pulling big loads:

1. The flip-back-and-forth motion, because you lose a few centimeters of progress every time you rest.

2. You’re hauling through a carabiner which is about 50% efficient, instead of a good quality progress capture pulley such as the Petzl Micro or Pro Traxion, which are rated about 90% efficient. For big walls, you definitely want a proper progress capture pulley!

Safety note: be sure to clip the rope into the carabiner along with that Tibloc when hauling! A common mistake is to set this up as a progress capture with the rope NOT in the carabiner. It appears to be working correctly, but as you can see below on the right, the rope is not clipped in. Probably not a catastrophic mistake if you're hauling a backpack, but if your load is more substantial, you want the rope running through the carabiner for sure.

Note for eagle eyed readers: this setup is slightly different than the one above marked “How to attach it”. In the diagram, Petzl says it doesn't matter whether you clip the rope inside or outside the carabiner. (I’m guessing that for simply ascending the rope under bodyweight it doesn't matter if it's clipped or not, but for hauling a potential large load, having the rope run through the carabiner is best practice.)

Related diagram from Petzl website:

And here's a nice video showing how to use it as a progress capture.

Use #4 - Simul-climbing protection - ADVANCED CLIMBERS ONLY

And finally, for the very advanced climber, the Tibloc can be used when simul-climbing to protect the leader from getting pulled off by the second. I remember when this idea was introduced in Climbing magazine around 15 years ago, and it was extremely controversial, Since then, it's generally become more accepted, but it's still an advanced technique; think of it as making a dangerous situation only slightly less dangerous.

Typically in simul-climbing, if the second falls, they will likely also pull off the leader. (This is also why the more skilled climber will usually go second, a reversal from normal climbing.) But, if the leader clips a Tibloc to protection, and the second then falls, the second will probably not pull the leader off.

Typically the leader will place the Tibloc AFTER a crux section, not before as with regular pro. This takes a little getting used to and can be easy to forget in the heat of battle, ask me how I know this. =^)

This is for advanced climbers only who clearly understand the risks of simul-climbing. There are a LOT of cautions and considerations to do this properly, way too much to get into here. I only mention it here because Petzl has it on their website as an approved technique, so it's not such a fringe, crazy idea anymore.

There's lots of info on the web about this if you want to read further.

• Here’s one image from the Petzl website, and you can read more about it here.

• Outstanding article from Brent Barghahn about simul-climbing with Micro Traxions

In real life, it looks like this: