I have been trying to find the "canonical" post on this topic without success - each post has its own take on the issue. And I understand that opinions and preferences abound - but I'm looking for sensible principles to apply (and resultant recommendations). Perhaps the most reputable discussion I found is on Mountain Project.

But if I were to summarize what I have learned I'd say that:

  1. You need two devices for redundancy, separate from each other as in this video:

enter image description here

and the Gri-Gri is not a valid alternative, despite some online presentations.

  1. Petzl Microcender seems to be a crowd pleaser, among other things, because it is toothless, and doesn't fray or peel on the rope. However, it has been discontinued. Same goes for the Silent Partner and the Soloist.

enter image description here

Are the Petzl Rescucender and the Trango Vergo the preferred alternatives for the primary device? For instance, on the Mountain Project forum, here, here and here.

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  1. What is the (or some of the) preferred secondary device? On the first image above, the secondary device (Handled Ascender) looks quite bulky... Should a toothed device like the Petzl Micro Traxion be a favorite option? By using it as a secondary device, you get all the benefits of a toothed device, but protect the rope since it will only get engaged if the primary device fails.

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Of note, I have also come across the recommendation of the Petzl Micro Traxion as the sole device as in this:

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The Yates Rocker and the Wild Country Ropeman mentioned by Climbing Magazine.

  1. Is it best to use a static rope (less elastic excursion; less problems with toothed devices) with two strands equalized via, for example, a figure 8 bunny ears knot at the top - one strand for climbing; the second strand as an escape belay or lowering (gri-gri) rope? This is probably shortsighted, giving priority to the rope over avoiding potential spine injuries with falls on static ropes - although possibly not all that likely...

4 Answers 4


You seem to have worked out many of the important principles that are needed for a system like this.

The most authoritative source that I know of is Petzl's articles on top-rope soloing. The downside is that they naturally only recommend Petzl devices. While some of their ascenders are recommended for top-rope soloing in the articles, they also mention others that are unsafe to use. In my opinion, the main takeaways from these articles are the following:

  • Top-rope soloing is more dangerous compared to climbing with a belayer. Because you are alone, you have only yourself to rely on to catch mistakes so there is less room for error.
  • Do not rely on a single ascender. While it may be unlikely, ascenders can fail (for instance if a foreign object gets inside) and this is likely to result in serious injury or death.
  • Use ascenders of different types. That way if one fails, the other is more likely to still hold since it is using a different mechanism.
  • If you use a toothed ascender, make sure that there will be as little force on it as possible in the case of a fall by minimizing the fall distance. Hard falls on toothed ascenders can strip the sheath off the rope.
  • The safest system for top-rope soloing uses two ropes with one ascender on each one. While more inconvenient, it allows for the possibility that a rope could be servered when it saws over a sharp edge while under tension. This is possible as has been shown in tests and is more likely to happen when top rope soloing because the same part of the rope can come in contact with the same area on the rock multiple times (particularly if you are working on a hard move).
  • Petzl recommends a dynamic or semi-dynamic rope of 10mm or greater diameter.

Petzl doesn't recommend against using a toothed ascender for the primary device. However, I personally have observed minor damage to the sheath of the rope during some test falls that I did, so I would only use a toothed ascender for backup. The damage wasn't enough to cause safety concerns, but I didn't really want it chewing up my rope over time.

I would not recommend using an assisted braking device such as the GriGri or Vergo for top-rope soloing. Unlike with an ascender, you would have to manually feed rope through it while climbing. Moreover, assisted breaking devices are not meant for catching a fall without the brake end of the rope being held. Finally, unlike some of the ascenders in the linked article, the manufacturers do not recommend using them for top-rope soloing.

Be careful about information you read online as I have come across a lot of bad information while researching this topic. It is important to verify anything you read (including this answer) and make sure that the system is sound by thinking about it carefully and testing it.

A good way to test the system is to attach your rope to a tree and do many test falls a few feet off the ground under the different conditions that you think you might encounter on a climb. That way you don't have to find out if the system works correctly when you fall halfway up a cliff :-)

Do not use the system unless it works perfectly in your tests and there are no potential problems with it.

  • +1 Any thoughts on static v. dynamic ropes for this? Commented May 27, 2019 at 22:50
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    @Enjoynature Petzl recommends dynamic or semi-dynamic rope that is more than 10mm in diameter. Static ropes have the advantage of being more durable and having less stretch which means you don't fall as far when you weight the rope. Dynamic ropes have the advantage of softer falls but the rope stretch will be more significant. Semi-dynamic seems ideal if you don't mind buying a rope just for top-rope soloing.
    – Qudit
    Commented May 27, 2019 at 23:07
  • +1 I like your link and interpretation of Petzl's appendix about the strengths, weaknesses and concerns of their various devices as used for self-belaying -- petzl.com/US/en/Sport/… .
    – Dave X
    Commented Jul 28, 2019 at 14:13

Good question and good answer by @Qudit.

I'd just like to add my thoughts on this based on own experience.

First of all, for info, I do TR solo for several years, using a Microcender as main device and Microtraxion as backup. Mostly with 2 ropes, but sometimes one rope only.

Different story, but for self belay while leading, I use similar setup as rappel in single rope: Grigri + prussik on the slack side of the rope. The prussik is to make sure the rope is caught in case the Grigri does not engage. But it is another hassle to feed rope through while leading. You do need a free hand for a longer time, so to reduce that hassle, I usually don't feed the prussik as often as the Grigri.

Into your points:

  1. Definitely 2 devices. Many things happen around your harness strong point, rubbing, jamming, entangling with rope, cross loading. In my opinion you're not really concerned about rope, carabiners or devices breaking, but rather slipping or not engaging. The 2-ropes setup is an added safety for (a) less interaction between the 2 devices and (b) rope protection due to sharp edges in the rock. So with some tidy setup of the devices (chest harness/sling, etc) and no issues with sharp edges, a single rope setup is good enough for me.

  2. Too bad Microcender has been discontinued =( But good thing is that I have one =) and it is awesome and reliable. Altough I've read reports of it slipping a little when wet, which never happened to me. Rescucender seems like a good alternative, due to the compact and design and its purpose. It is really an update of the Microcender in terms of handling, but I've never used it. I would not consider a Vergo, for the same reasons I would not consider a Grigri to TR solo - too easy for it not to engage (although I do use a Grigri for lead self belay, but that's mainly due to lack of alternatives, as mentioned above).

  3. Microtraxion is definitely a good device in my opinion. Since it is toothed it is a lot safer in not slipping and biting into the rope. I think worries with the rope sheath are overrated and over discussed - it is a backup system, in case it does take a hard fall, it means that something else already went wrong, hence the least of my concerns is damaging the rope sheath.

  4. Static ropes are fine, and by fine I mean there's no show stoppers in the literature and experiences screaming for "don't use static topes for top rope!". However my personal preference is dynamic ropes due to less loads involved in the entire system. The additional stretch and yoyo-like feeling is more of an annoyance rather than a safety hazard. And hey, you need to do something with your good old dynamic ropes after retiring them for leading =) As for the one vs two strands, as discussed above in point 1, if you do go through the hassle of installing a double strand at the anchors, do use them both for your safety while climbing, ie, main device in one rope and backup device in secondary rope. Unless of course you're really willing to repeat the same move on a route multiple times, them in this case it would be much easier to do as you say and have a Grigri, or Vergo, in the second rope, or something promissing but as far as I know little tested in this scenarios, a Camp Goblin

Another point I'd like to add is to protect the rope well and pay attention to where it is contacting the rock. In a solo TR, the rope is "static" in the rock, and the same part of the rope will repeatedly rub and wear against any sharp edge or crystals. So there's where 2 strands are awesome, but also consider that your anchor really have the 2 strands independent from each other. Do make sure you use a knot strong enough to hold the tension in one strand with the second strand completely slack. It may sound silly but I've seen people (it may well have been myself many many years ago as a beginner =P) TR soloing with the rope rigged for rappel, ie, you actually double your problems, if one of the two rope breaks, your next stop is the ground. But with 100's thing in my head when I setup the system, that little detail didn't get into my attention. All that to reinforce the idea that when you're soloing in any way, you do need to think consequences, holistically and triple check everything.

Stay safe and have fun =)

--- edit --

A bit more on a primary device I've just got to know, the TAZ LOV3. Seems to be pretty good and ready for ascending and descending. Since it needs to be free to engage to lock, I'd still use it with a Microtraxion as backup.


Before sharing what I have been doing, I have to remind anyone reading that the most widely accepted set up follows the Petzl recommendations:

enter image description here

and I certainly would suggest anyone to pay attention to their recommendations, considering what follows just what someone online without any authority in the matter has been doing for a few years now.

I use two strands of a static rope, tied at the anchor via two independent locking biners and a double figure-8-bunny-ears knot - one biner for each "earlobe" tied to a different bolted anchor, or sling around a tree, as the situation presents itself.

I use both strands tied to my harness loop via a locking biner and two side-to-side Micro Traxion devices. After coming across this post showing how twist-lock gates can be opened by the rope, I changed the configuration in the picture to a screw-gate pear-shaped locking carabiner:

Old method (self-locking biner with two MicroTrax's):

enter image description here

New method (screw-gate locking biner with two Micro Traxion's):

enter image description here

Cross-loading the biner has never been an issue for me, but it required some adjustments at times, so I am more recently using a Climbing Technology Concept SGL with an ACL system to prevent this issue:

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In addition, I have incorporated a clove hitch on a locking biner to one of the strands of static rope below me (see second image above). As I climb, I periodically slide up the clove hitch without unclipping the biner, simply by pulling up on that strand and sliding the rope. In this way I keep the extra safety of the clove hitch on the biner relatively close to me. Its function would be to act as the ultimate safety if both Micro Taxion devices were to strip the rope on a fall, or failed for other reasons.

At the bottom of the crag, I used to tie the ends of the rope to my backpack through a single clove hitch tied with both strands and secured through a biner to passively help with the sliding up of the Micro Traxion devices as I climb:

enter image description here

However I abandoned this system because the weight of the rope tends to be enough to make the MicroTs slide as I climb above some 20 feet off the ground, and having the backpack tied to the end used to be a constant source of annoyance.

The two-strand setup offers redundancy, but also allows the Micro Traxion devices to stay parallel to each other, as opposed to in line as in here. I find that having the Micro Traxion's one after the other on a single rope wedges them together splaying the orange casing of the top one.

If I need to ascend and top-off, or descend from a point without support I use a Jumar (*) to disengage the MicroTraxion's (impossible under weight).

However, and as an alternative, one of the strands of the rope will come handy in releasing the tension in the system: I can tie an alpine butterfly knot on the strand that will not be used to descend to provide me with a way of placing a foot through it and stepping up on it to release all tension on the harness loop at which point I simply open the biner, leaving the Micro Traxion devices on the rope until I have all my weight on the descending device (usually a GriGri, or Munter knot as an alternative). This is the picture of the alpine hitch on the non-descending strand ready to step on:

enter image description here

Naturally, before I disengage the Micro Traxion's I already have a GriGri or a Munter knot set up on the descending strand. The GriGri is most efficient, and easy on the climber and the rope, but I want to illustrate the Munter since it is the back-up system when the GriGri is dropped by mistake during the setup process. Here is a quick home-made video of the tying up of the Munter knot before disengaging the Micro Traxion's. This is the picture of the Munter before backing it up:

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Typically, the Munter is backed-up with a mule hitch and an overhand knot:

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Here is an image from this great animated illustration of the Munter with a mule hitch back-up by knots by Grog of what the steps are (Munter, mule, backup half-hitch):

enter image description here

I tie up the Munter a bit differently (as on the link above) because it makes it easier to set up the Munter ready for rappel (braking end away from the gate). Here is the entire process of setting up the Munter-Mule with a clove hitch as a back-up, and the alpine butterfly to relieve weight of the Micro Traxion's.

After I release the Micro Traxion's, I hold on tight to the loop in the mule hitch and compress from top to bottom the Munter to keep it from sliding down. It is important to watch for cross-loading on the biner, and try to get the loops of the Munter along the basket of the biner parallel to each other.

In addition, I do tie a second clove hitch lower down from the Munter on the descending strand of the rope, fastened to the loop of my harness (tied below the HMS biner for the Munter with a self locking biner), which I disengage only when the Munter is already in rappel mode (i.e. after untying the overhand and the mule hitch). The clove hitch is more often than not the only "back-up" for the Munter (in lieu of the mule).

Before unfastening the overhand knot and the mule hitch from the Munter, I make sure to adjust this back-up clove hitch so that it is at some distance from the Munter in case this slides down a bit while disengaging.

(*) Carrying a Jumar is always a good idea, because the way out of a situation may be climbing up, rather than lowering oneself. In the absence of a Jumar, this can be done with two Prusik knots.

  • Good to see that you master the Munter as a backup technique =) Instead of the backup with the Mule + girth hitch, have you tried to first tie a prussik knot to a locking carabiner on a harness leg, then pull some slack and do the Munter/Grigri? Like that you have a backup and are ready for rappel.
    – Raf
    Commented May 26, 2021 at 9:11
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    @Raf The truth is that with a GriGri it is a very fast process without much need for anything else (just the Jumar to disengage), but I have dropped the GriGri in the past, and always found myself sliding a bit with a Munter without the whole backup. It's no problem, but I had been trying different methods to make the transition as smooth as possible. I'll try what you propose. Thank you. Commented May 26, 2021 at 10:00
  • On another note, to be honest I find it a little sketchy to put both Traxions on the same carabiner. I'd really prefer two of them to keep redundancy across the system. If space if a problem, you could consider 2 D maillons attached parallel to the loop. They occupy little space, drawback is a little longer time to assemble.
    – Raf
    Commented May 27, 2021 at 11:57
  • @Raf That is a valid consideration, and striking a balance between personal comfort and risk one feels is acceptable may come down to a personal decision, and tons of trial and error experimenting in the safety of a controlled environment. I edited the post with the Petzl recommendations to place my contribution at a the level of a humble suggestion / sharing my how-to recipe. Commented May 27, 2021 at 12:56

I do greatly enjoy using a single LOV3 attached with a quick link for TRS cause you can go up and down as you see fit and do laps easily. (I would occasionally use backup knots). I also very much like using a Scroll (from caving) + a MT as this is super smouth and feels super secure. And finally I would use two MT on two half rope when its the only rope I have.

  • I watched a presentation by beta climbers, who seemed to really like it.Here is the link. Commented Jan 10, 2023 at 12:42
  • I feel this answer also needs a lot more detail. Can you please edit it in?
    – Willeke
    Commented Jan 10, 2023 at 20:34

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