# GRIGRI & 13mm



## SINGLE-JACK (Nov 23, 2009)

The Petzl GRIGRI is rated for use on 10-11mm rope. Anyone have experience, pro or con, with using a GRIGRI on 13mm (1/2") rope?


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## Norwayclimber (Nov 25, 2009)

It locks up really easily, the problem is when you try to give rope out or lower on it. When lowering you have to open i wide up, and you get a "jumpy" or "unsmooth" lowering.

I wouldnt recomend it if your gonna use it as a selfbelay on srt, but I guess it can be used as a lowering device, but it aint that good.

Can also be used to tie the srt rope of at the base level of the tree, so that the groundmen can lower you down in an emergency, but I find the munther hitch just as good, and a grigri cheaper.


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## SINGLE-JACK (Nov 25, 2009)

Norwayclimber said:


> It locks up really easily, the problem is when you try to give rope out or lower on it. When lowering you have to open i wide up, and you get a "jumpy" or "unsmooth" lowering.
> 
> I wouldnt recomend it if your gonna use it as a selfbelay on srt, but I guess it can be used as a lowering device, but it aint that good.
> 
> Can also be used to tie the srt rope of at the base level of the tree, so that the groundmen can lower you down in an emergency, but I find the munther hitch just as good, and a grigri cheaper.



Yeah, I was fairly sure what kind of answer I would get. I really like the GriGri concept but got big hands and all my ropes are 13mm. I checked out the large "I'd" - it's huge and cost twice as much. The spiderjack is three times as much. Then there's the unicender at $450. 

Still looking for best single mechanical device that will do it all - ascend, descend, & limb walk - probably doesn't exist yet.


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## Tree Machine (Nov 28, 2009)

I would be happy with a device that _just does descent_ on doubled twin line (1:1 or DbRT), 2:1 doubled dynamic (DdRT) and SRT and that would handle ropes from 10 mm through 13 mm AND had intrinsic soft-lock, hard-lock options.

I think that the being able to both ascend and descend off the same device is grossly overrated. It pretty much demands that your ascent be 2:1 and that's takes any real efficiency out out of the picture. 2:1 descent is OK, but then you need to add into the equation a friction saver and the time in setting and retrieval, or deal with the friction and potential damage to the cambium. Also setting redirects, or going around stems, through natural crotches.... anything that puts pressure on any part of the rope adds friction and affects performance. 2:1 ascent requires so much slack tending. 2:1 ascent or descent works best if you stay to one side of the tree and have no limbs interfering.

Here's a question. If it takes 6 or 7 seconds to place the descent device onto the rope, is it really necessary to be able to instantly go from ascent to descent?

To me, a few seconds IS essentially instant (with the exception of bees buzzing around my head). I'm happy to pay the small price of switching over if I can enjoy all the benefits a 2:1 climber can't fully realize.

The only time I use 2:1 descent any more is on takedowns, after the crown is out, coming straight down to take a break, that is, if I'm not anchoring up top to descend SRT (no natural fork remaining) or twin line descent (which I'm still more likely to choose over 2:1)


I see an all-in-one looking like a dual ascender with friction control abilities.
For now, a dual ascender and adding a friction controller when needed is as close as you're gonna find, but with under 10 second switchover you have to ask, is an all-in-one system REALLY necessary?


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## Tree Machine (Nov 28, 2009)

But this thread is about a grigri on 13 mm. You can _stuff_ a 13 mm rope in there, and I've done it. It works, but I shy away from systems that 'work' but don't offer any real advantages or versatility.

I used the grigri on a 13 mm flipline for awhile. That was nice in that the grigri on 11 mm can slide if not weighted sufficiently. Partially weighted on 11 mm, the cam does not engage, or stay engaged without enough tension. See Petzl's GriGri instruction sheet on securing the tail of the flipline to accomodate this annoying little behavior.

On a 13 mm the slippage is overcome, but replaced with the annoyance of extra friction and resistance when adjusting in. Then there's always the issue of finding the cam release handle, getting it out of it's recess and arcing it over to the point where release of the cam is possible. Then, as Norwayclimber points out it has a sweetspot, a very narrow range where the ideal friction is applied to the rope.

In reading this it may appear that I don't care for the GriGri. Actually, I like the device very much, I think the concept and design are genius, I keep trying it in different places where a single line is the mode. Since I go back and forth between twin & single, a grigri keeps you limited to use on one line at a time.

I approached Petzl a few years back at an EXPO on a dual gri-gri, something you could use on twin OR single, whose (dual) lines could be controlled simultaneously or independently. They chuckled, but stopped short of laughing at the idea. But I wasn't joking.

Dual line control is the least explored version of all the rope techniques. Very few devices are made for this style of descent. Dual line _ascent_ is now covered very well (finally).


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## Tree Machine (Nov 28, 2009)

Is a limbwalk considered descent or adjusting out?


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## Tree Machine (Nov 29, 2009)

No, I _don't_ switch gear when I lengthen and shorten the length from my tie-in point. I only switch over to descent when it's time to descend. Otherwise I stay on a 1:1 method, whether SRT or twin line. The descent is also 1:1, whether SRT or twin line. 2:1 DdRT descent is easily possible, but rope wear and cambium damage and limitation of full-factor travel are negatives, so used infrequently.

Having the flexibility of being able to utilize any of the three rope techniques, interchangeably is the tree climbing world I work in. It's nice, you just need to, or should, switch over for descending out of the tree, or onto a roof. I guess the key is knowing the difference between what is descent and what is simply downward adjustment within the crown.

Not meaning to derail this side conversation, but this side conversation is a derail of the thread.

I apologise to the readership if I shifted the thread this direction.

The grigri can only allow you two of the three rope techniques. It CAN let you descend SRT and it CAN sub in for a friction hitch and allow 2:1 DdRT style descent, which I believe SingleJack might be specifically asking about. You can pull slack through pretty well when adjusting up with 11 mm rope, and you just have to pull slack with more effort when using 13 mm.

I'm currently using the GriGri on my flipline, trying out a 10-foot long, 13 mm diameter eye-eye lanyard at the moment. Honestly, the device works much better on 13 mm than on an 11 mm flipline, but this system overall isn't really performing well. No real problems, just many other ways that are so much better.


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## SINGLE-JACK (Nov 29, 2009)

Tree Machine said:


> No, *I don't switch gear when I lengthen and shorten the length from my tie-in point.* I only switch over to descent when it's time to descend. Otherwise I stay on a 1:1 method, whether SRT or twin line. The descent is also 1:1, whether SRT or twin line. 2:1 DdRT descent is easily possible, but rope wear and cambium damage and limitation of full-factor travel are negatives, so used infrequently.
> 
> Having the flexibility of being able to utilize any of the three rope techniques, interchangeably is the tree climbing world I work in. It's nice, you just need to, or should, switch over for descending out of the tree, or onto a roof. I guess the key is knowing the difference between what is descent and what is simply downward adjustment within the crown.
> 
> ...



The specific question of the OP was about the GriGri in hopes that it would be *the answer *to the broader question about optimization of movement about the tree with minimal gear. This "side conversation" seems to be addressing that exact "broader question" of efficiently moving about the tree. 

I've already picked-up on the very interesting technique of using a cammed ascender for movements about the crown _("I don't switch gear when I lengthen and shorten the length from my tie-in point.")_. 

*So, please, "derail" away ... *


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## Tree Machine (Nov 29, 2009)

SINGLE-JACK said:


> *So, please, "derail" away ... *



No, let's keep a GriGri thread about the GriGri.




SJ said:


> The specific question of the OP was about the GriGri in hopes that it would be the answer to the broader question about optimization of movement about the tree with minimal gear.



The November '09 TCIA lead article addresses this in depth with lots of pictures, but only the *ascent /movement about the crown / work positioning*. The final descent is not covered in the article as there are likely hundreds of options for controlling friction to do a controlled slide down a rope. But that is just a tiny portion of what Arborists do in a tree. 

The GriGri can do the final descent using two of the three rope techniques, but it's rather bulky, weighty and expensive, and as Norway says,


> I wouldnt recomend it if your gonna use it as a selfbelay on srt


. With this, I have to agree.


Looking back, I DO see your broader question,


> Still looking for best single mechanical device that will do it all - ascend, descend, & limb walk - probably doesn't exist yet.



That research is in active mode, but if the 'ideal' device optimizes one rope technique by limiting the others, then your methods are limited.

Keep plugging. I find treeguys to be very innovative.


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## SINGLE-JACK (Nov 29, 2009)

Tree Machine said:


> No, let's keep a GriGri thread about the GriGri.
> ...
> The GriGri *can *do the final descent using two of the three rope techniques, but it's rather bulky, weighty and expensive, ...



OK.

That implies you do not use the GriGri for descent and begs the question: What is the better (best?) alternative to the GriGri for descent?


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## ForTheArborist (Nov 29, 2009)

Exactly. What is better than a Gri Gri, but more specifically what can gradually and smoothly let you descend inch by inch as well as lock you there as you turn to make a cut?

I went to browse our local REI for gear, and they have the Gri Gri and Petzl Descender which is a blue, elongated device both for $100. I talked to the sales climber to find out that the Descender is jumpy while the Gri Gri is smooth in their descents. The Gri is actually lil' cheaper too. I'm buying one tomorrow to give it a test drive, but I might buy something else next month. 

What could be better than a Gri Gri for smooth and inch by inch descending without the popping and jumping as you drop past your branch by a few?


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## newsawtooth (Nov 29, 2009)

Is there any evidence of Gri-Gris failing when used with larger than specified diameter ropes? I prefer 1/2" ropes for most applications. In SRT configurations we are limited to just few options, none of which are ideal. I have been using a prusik above a prana descender for work positioning. Not terrible, but not as smooth as a Gri-Gri for adjusting or limb walking. So, I continue to look for a device that does at least 2 things well, descend and work positioning.


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## Tree Machine (Nov 29, 2009)

It's nice to see you guys are exploring devices more and more.

I would share info on mechanical devices five or six years ago and threads would just sorta stop with an uneasy silence, like dropping an F-bomb in church.

Now that more and more guys are exploring the benefits of SRT and seemingly getting to the point where, as a whole, we are seeing that_ to fully realize all the advantages_ we need to let go of the friction hitch and use highly specialized devices. The friction hitch really only works in 2:1 DdRT (dynamic doubled rope technique), and therefore locks you out of two other excellent rope methods, both 1:1.

Overcoming mechanical device-aphobia is tough when the friction hitch is all you've ever known, and unless you mix with search and rescue, cavers, tower climbers, fire, alpine and rock people you won't see much else. All you see is what other tree guys show you, and that is modified and fancied-up 2:1 systems, much the same in practice as way back in the manila rope days before mechanical gear existed. It's the same general method, passed down through many, many generations and incorporates high-tech cordage and caribiners as the only real difference. Throw a pulley and a dog snap in there, a spliced, $40 technora eye-eye tress cord, you still have 2:1 ascent and a heck of a lot of slack management.

The grigri is really a well-designed and excellent device, pretty bombproof in answering Newsawtooth's question. I think it should be part of every treeguy's kit. It was originally intended for a belay person on the ground to control the rope of a (rock) climber above, but it has found a great many more uses in all the rope disciplines. I've found a good number of unconventional uses in treecare, as well as for the flipline adjuster and SRT self-belay.


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## Tree Machine (Nov 29, 2009)

ForTheAction said:


> Exactly. What is better than a Gri Gri, but more specifically what can gradually and smoothly let you descend inch by inch as well as lock you there as you turn to make a cut?



You can pick from here or from here. You'll see a lot of options, but not the one _ideal_ self-belay device specifically engineered for tree climbing.

Ideally, ForTheAction, both your ascender AND descender should fulfill this purpose of movement about the crown and high-precision control of positioning. That way, if either will work as well as the other, you don't have to decide which is better in the moment because either will work equally well as one another and therefore you don't have to switch devices. A good pairup should allow a w i d e c r o s s o v e r where each device should be able to do the same thing as one another once up in the canopy, as far as getting up and down and around the crown and stationary work positioning. Whether you do your work off the ascent device or off the descent device should be a case of whether you're working your way up the tree, or working your way down the tree, But once in the crown (generally speaking) you should be able to g_o upwards using the descent device_ or _down using the ascent device._ 

Yes, you're reading that correctly. I know this sounds 100% counterintuitive, but if the devices are well designed, it can be so. This offers a remarkable degree of flexibility and options, and an ease of climbing and work positioning, safety and confidence that I feel is what we are all striving for in the big picture.

The industries who make our gear _almost_ have the ideal ascender nailed down. It does exist, but is not available commercially. The ideal descender ( I prefer the term _self-belay device_) is more in concept at the moment, I don't think even a solid prototype has been created, though a solution has been conceived and *is* being proposed to these companies, namely ISC of Wales and Petzl. The problem is, they're not listening real well. 

Other arborist forum sites have in-depth discussions where this information is shared in enormous depth. I can't mention those sites or offer a link to specific threads or I will have my :censored: banned from here before I can say :censored:. Heh, heh.


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## newsawtooth (Nov 30, 2009)

Is there a definitive answer regarding using 13mm line in Gri Gri's which are rated for 11mm? Do larger lines push out on the cheeks when they flatten under load? Anyone sprung for the Wren Silent Partner? The good Dr. S likes it, is there an application for it in Arboriculture?


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## brnchbrkr (Nov 30, 2009)

Tree Machine said:


> You can pick from here or from here. You'll see a lot of options, but not the one _ideal_ self-belay device specifically engineered for tree climbing.
> The industries who make our gear _almost_ have the ideal ascender nailed down. It does exist, but is not available commercially. The ideal descender ( I prefer the term _self-belay device_) is more in concept at the moment, I don't think even a solid prototype has been created, though a solution has been conceived and *is* being proposed to these companies, namely ISC of Wales and Petzl. The problem is, they're not listening real well.



When they get the fat bastard ascender out to the public, I might be able to climb then. ;-) Got me thinking and searching.









if this offends the forum, please delete.


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## SINGLE-JACK (Nov 30, 2009)

newsawtooth said:


> Is there a definitive answer *regarding using 13mm line in Gri Gri's* which are rated for 11mm? Do larger lines push out on the cheeks when they flatten under load? Anyone sprung for the *Wren Silent Partner?* The good Dr. S likes it, is there an application for it in Arboriculture?



The *Wren Silent Partner also has an upper limit rating of 11mm *and is nearly three times the cost of the Gri Gri.

Also from the manual:
_"The Silent Partner self belay device is not recommended for routine
rappelling. It does not provide much friction, and it will force you to
rappel very slowly. Whenever possible, use a conventional rappel
device for descending."_

*Again, is their any first hand experience "regarding using 13mm line in Gri Gri's"?*


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## ForTheArborist (Nov 30, 2009)

Tree Machine said:


> You can pick from here or from here. You'll see a lot of options, but not the one _ideal_ self-belay device specifically engineered for tree climbing.
> 
> Ideally, ForTheAction, both your ascender AND descender should fulfill this purpose of movement about the crown and high-precision control of positioning. That way, if either will work as well as the other, you don't have to decide which is better in the moment because either will work equally well as one another and therefore you don't have to switch devices. A good pairup should allow a w i d e c r o s s o v e r where each device should be able to do the same thing as one another once up in the canopy, as far as getting up and down and around the crown and stationary work positioning. Whether you do your work off the ascent device or off the descent device should be a case of whether you're working your way up the tree, or working your way down the tree, But once in the crown (generally speaking) you should be able to g_o upwards using the descent device_ or _down using the ascent device._
> 
> ...



I've seen a piece that does what you are talking about. It's comprised of 4 small, silvery, metal blocks that move to lock the rope etc. I can't find it right now.

As far as descending smoothly, and then locking off, I just suppose now that an 8 would serve that purpose. After taking a look at the descender below





I see that there is a place for tieing up. I have an ol' Trango 8 which has no place to tie up to, but I suppose if I bought one of the newer, bigger 8s with the horns for tieing up, I could easily lock myself in place after descending to the point within the tree to make a cut. 

Somebody tell me if this isn't the most ideal way about it or not. The 8 in tandem with a Blakes Hitch would be cost efficient and ultra smooth I think.


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## SINGLE-JACK (Nov 30, 2009)

SINGLE-JACK said:


> ...
> *Again, is their any first hand experience "regarding using 13mm line in Gri Gri's"?*



Well ... I managed to borrow a GRIGRI ... tried it (unloaded) with Yale XTC Fire (12-13mm), Yale XTC 12 (12mm) and Sterling HTP (7/16 - 11mm). Sherrill lists the Fire at 13mm but Yale lists it at 12mm. 

Anyway, they all fed through the GRIGRI quite nicely. Since it's raining and the GRIGRI is not mine, I did not climb with it but the 12mm's actually seemed a little better than the 11mm.

As TM suggests, it looks like it will be a good addition to a climber's kit.


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## Tree Machine (Nov 30, 2009)

ForTheAction said:


> I've seen a piece that does what you are talking about. It's comprised of 4 small, silvery, metal blocks that move to lock the rope etc. I can't find it right now.


It's called a rack, all my caving buddies use them. Racks are available in all sorts of forms. We don't use them in the trees. They're one way down, you can't pull slack through them. No upward adjustability, useless IMO, unless you're dropping a pit or rappelling off a cliff. Plus they're long, anything but compact.



ForTheAction said:


> As far as descending smoothly, and then locking off, I just suppose now that an 8 would serve that purpose.


Twists the rope. I've got 5 fig 8's, and keep a Petzl Pirhana on my saddle at all times. But I never use it. Or any of them. A nice one came out recently, it looks like this: 





But pulling slack through any 8 is no fun. They WILL allow any of the three rope techniques, but on doubled twin line the rope friction is doubled, and slack tending is double PITA.


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## Tree Machine (Nov 30, 2009)

> After taking a look at the descender below
> 
> 
> 
> ...



The term is 'locking off' A 'soft lock' will offer enough friction to hold you in place, but by pushing (feeding) the rope up (from below the device) you can adjust yourself downward. 'Hard lock' locks you in place, period. You have to remove the rope from the lockoff position to continue downward. A good device should allow both soft lock and hard lock, though soft is used most often, unless you plan to spend a lot of time hanging out at one level (cabling, for example).




> Somebody tell me if this isn't the most ideal way about it or not.


 No.



> The 8 in tandem with a Blakes Hitch would be cost efficient and ultra smooth I think.


Complicated, time consuming, requiring two hands to do any moves. Why not just use the Blake's alone? Why stick an 8 in the midst. You use an 8 so you don't have to use a hitch.


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## Tree Machine (Nov 30, 2009)

SINGLE-JACK said:


> Is there a definitive answer regarding using 13mm line in Gri Gri's which are rated for 11mm? Do larger lines push out on the cheeks when they flatten under load?
> 
> Again, is their any first hand experience "regarding using 13mm line in Gri Gri's"?



Here's the official answer; Don't use a device on a rope size for which it is not rated. The GriGri is not rated for 13 mm line.


The unofficial, I have used it on 13 mm line many, many times. Back when I climbed on 13 mm line I played with it, experimenting on my own, SRT and on doubled rope as a replacement for a friction hitch. It wouldn't do dual line, though, so I moved on.

I use it for taking down tall, thin trees from the bottom up (tight area, can't fell it); anchor 13 mm line to the top of the tree being taken down, run it through a crotch of an adjacent, larger tree. anchor the grigri to the base of the nearby tree with a lifting sling, run the 13 mm rope through the GriGri and pull as much slack through as you can. Cut the base of the tree to be taken down. Take out a 16" block, slide the tarp underneath and then lower the tree to where it just touches the tarp. Cut out another 16" block, lower with the GriGri, repeat until you're into brush. Limb it out into a pile onto the tarp. All the mess is really tidy, sawdust and all.

I don't think the trees I've done like that were more than 4 or 5 times my weight, but the GriGri works really well. Oh, by the way, you _should NOT _use a GriGri in this manner.


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## Tree Machine (Nov 30, 2009)

I use it in a 3:1 configuration to hoist sometimes, again with 13 mm.


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## newsawtooth (Dec 1, 2009)

Thanks for the input TM. I will stick with the modified prussick prana combo for SRT until a better mechanical device emerges or I switch to lighter line. 

Why do you like the option of using a double line?Ease of foot locking? For clarification, I am referring to a rope that is hung equally from a TIP where both ends remain on the ground for ascent not DRT.


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## SINGLE-JACK (Dec 1, 2009)

Tree Machine said:


> Here's the official answer; Don't use a device on a rope size for which it is not rated.
> 
> ... used it on 13 mm line ... for taking down tall, thin trees ...
> 
> *Oh, by the way, you should NOT use a GriGri in this manner*.



Good idea! I've done "bottom up" this way a lot, as a leaner, ie. without the tie-off and lowing line. It's a neat, tidy technique.

*Oh, by the way, I would NOT use a GriGri in this manner*.


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## SINGLE-JACK (Dec 1, 2009)

Tree Machine said:


> I use it in a 3:1 configuration to hoist sometimes, again with 13 mm.



Apparently, a GRIGRI with 13mm can easily function with a higher load than a climber's weight. 

Have you noticed any 'wear' issues?

It seems the RAD (Yo-Yo) method is the only way to replace the friction hitch with a GRIGRI for DdRT (2:1) & SRT. I'm not convinced the pulley is necessary, yet.

Also, the GRIGRI does not seem foot-locking friendly. True?

If a 'DOUBLE' GRIGRI existed, would that change your opinion about using it as a climbing/workiing/descending aid?


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## Tree Machine (Dec 1, 2009)

newsawtooth said:


> Thanks for the input TM.
> 
> Why do you like the option of using a double line?Ease of foot locking? For clarification, I am referring to *a rope that is hung equally from a TIP where both ends remain on the ground for ascent not DRT*.



Newsaw, I could go on and on. For clarification, though both ends of the climbing line are on the ground, it isn't hung equally. It _can_ be hung equally, or one end can be just touching the ground and the remainder in a pile or in your rope bag, OR both ends can be up in the air (i.e. 150 foot rope, 80 foot tie-in point) in the latter case, your first footlock would look like this:




For this you would sorta hip-thrust up to the point where you could get your heels over your stopper knots, then a couple more feet and you're good to go..... now this is a rarity, and not recommended, but when you ace an 80-footer on the first shot, you just don't want to pull it so you can try again for a lower crotch. SRT wouldn't have allowed this, nor DdRT. Twin line, it was like, cool, this adds an interesting element of challenge. Once up there you can reset your rope lower.

I'f Id have had to pull that 80 footer out, you know dang well it would be 3 or 4 more failed shots before nailing one at 70 feet.


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## Tree Machine (Dec 1, 2009)

newsawtooth said:


> Why do you like the option of using a double line?Ease of foot locking? For clarification, I am referring to a rope that is hung equally from a TIP where both ends remain on the ground for ascent not DRT.



I could go on and on, but that would be a definite derail of this GriGri thread.


I'll offer one of the reasons, not even in the top 5 of my favorite reasons, but it goes back to something SingleJack said earlier, *big hands*. On twin line, you grab the rope with your hands (as we all do) an 11 mm line is 22 mm, as far as your hands are concerned.


Also, Newsawtooth, it's not a double line. That would be TWO lines. I like to use the term twin, or twin parallel. Many call it doubled static.

Also, I don't use it as an option, I use it because of the different _options_ it offers.


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## Tree Machine (Dec 1, 2009)

SINGLE-JACK said:


> Have you noticed any 'wear' issues?



After 10 years??? Yea.... it looks like it's ben dragged behind a truck. However, I inspect it frequently and pay close attention for any type of change in look or feel, in opening, closing, installation and in use. It works just like the day I bought it.



SINGLE-JACK said:


> It seems the RAD (Yo-Yo) method is the only way to replace the friction hitch with a GRIGRI for DdRT (2:1) & SRT. I'm not convinced the pulley is necessary, yet.



You mean, specifically, for _ascent_ 2:1 and SRT. Nothing additional is needed for descent.

For RAD ascent you need a rope grab above to act as a hoist point because you'll be hoisting yourself up a few inches, moving the rope grab up, hoist again.... all so you can use the GriGri on both ascent and descent. I'd rather swallow glass.



SINGLE-JACK said:


> Also, the GRIGRI does not seem foot-locking friendly. True?


Only possibility is in RAD configuration for ascent. Please refer to the 'I'd rather eat glass' comment. The GriGri is not designed or intended for ascent. True, you can work it out so that you can, but at a great cost of efficiency and extra pieces.



SINGLE-JACK said:


> If a 'DOUBLE' GRIGRI existed, would that change your opinion about using it as a climbing/working/descending aid?


I'd have to try it, for sure. It would need to, as stated earlier, be able to control one or the other side independently, or both sides simultaneously. That's what I'm used to and I find advantages in having that versatility.


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## Tree Machine (Dec 4, 2009)

newsawtooth said:


> Why do you like the option of using a double line?Ease of foot locking?



Parallel, twin, doubled static, = twice the rope at your feet, twice the friction. You minimize the friction at the dual ascender above you and you maximize the friction at your feet, below you. It's a combo that makes it almost like cheating, compared to a DdRT friction hitch system (or any 2:1 or Z ascent method).


Climber's try to find advantage wherever they can get them. This is a big one.

Sorry that this thread keeps getting derailed.

~~~~~~~~~~~~

A dual GriGri could be an ideal pairing with the single handle dual ascender. 

I'm not the first to have thought of this dual GriGri. Here's a conversation in this GriGri data report



"Gary, I hear you don't like the Grigri."

"Yes."

"In fact, I heard you say that it ______."

"Not exactly, but I'll go along with that, for my purposes."

"Tell me one thing - just one thing - wrong with the Grigri!"

"You can't use it to rappel on doubled rope."

"OK, tell me another."

"Well, since I'm now carrying another device to let me rappel on doubled rope, it weighs more than nothing and is bigger than nothing."


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## Tree Machine (Dec 17, 2009)

A double-GriGri would not offer good slack-tending , just by itself. You'd have to work for it.

In a dual-line belay device, you want friction maximal on the out and minimal on the in. You want the tending-side friction to be so minimal that at about 40 feet, there is enough rope weight below you that it pulls it's own self through the friction device as you climb upward toward your tie-in point, true self-tending. Double gri-gri wouldn't allow this.


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