Thin ropes and a grigris

I'm wondering if/what would happen if I top rope belayed with a grigri on a 7.9 mm rope. I'm not going to be leading with one of these ropes but I want the abilities of the grigris but don't want to spend money on another belay device. Thoughts on this?

Try it out close to the ground! I think most Grigris are only rated down to 8.5, so the cam will likely slip a bunch and potentially not work at all. I have an 8.5 that I really enjoy lead belaying with a greeg. Super smooth. You just have to make sure you have good belay technique.

I've been testing it and it catches with a small amount of slipping right at the catch. But I'm wondering what others thoughts are. And thank you 

Billy Uhlhorn wrote:

I'm wondering if/what would happen if I top rope belayed with a grigri on a 7.9 mm rope. I'm not going to be leading with one of these ropes but I want the abilities of the grigris but don't want to spend money on another belay device. Thoughts on this?

If the gri says its not rated for it, don’t do it, or pay the consequences.

I was once rapping on a grigri 2 on a ~9.0mm rope with a pig. I suddenly started falling down the rope, so I let go of the brake handle and pulled down hard on the brake strand. I was able to brake much harder than I would have been able to otherwise as I was wearing my wall gloves. I didn't stop falling for around 20'. 

If you're going to go below rated specs use a grigri 3 for sure which is rated down to the smallest diameter of any grigri, but that experience has forever made me fearful of using ropes even at the outer limits of what a grigri is rated for. 

The Protect Pro 8.9mm rope seems to work fine in my Grigri 2 but it also has a weird sheath that seems to add a ton of friction. 

I would strongly caution against this idea, especially when geometry assisted devices designed to work with these ropes such as the micro jul are very affordable. 

Billy Uhlhorn wrote:

I'm wondering if/what would happen if I top rope belayed with a grigri on a 7.9 mm rope. I'm not going to be leading with one of these ropes but I want the abilities of the grigris but don't want to spend money on another belay device. Thoughts on this?

Why would you TR on a 7.9? I can see if you're leading a 60m long pitch with doubles and want to go back down to belay but you'd have an appropriate belay device in that case. Bring a fatter rope or use a Munter. You're going to lose more money banging out your skinny rope than it costs to get an alpine ATC.

$.02

rocknice2 wrote:

Why would you TR on a 7.9? I can see if you're leading a 60m long pitch with doubles and want to go back down to belay but you'd have an appropriate belay device in that case. Bring a fatter rope or use a Munter. You're going to lose more money banging out your skinny rope than it costs to get an alpine ATC.

$.02

I recently got 2 of the in basically new condition used 3 times from a friend for under a hundred dollars and I don't want to burn through my leading rope. And I'm looking for something that's auto locking 

Billy Uhlhorn wrote:

I recently got 2 of the in basically new condition used 3 times from a friend for under a hundred dollars and I don't want to burn through my leading rope. And I'm looking for something that's auto locking 

The grigri doesn’t autolock reliably once you get below 8.5m so the benefit of the device is moot.

This is sorta one of those questions if you have to ask the question you probably don’t have the experience or expertise to be doing it.  

Sounds like your buddy sold you a pair of half ropes. Since you don’t want to use them for their intended purpose, perhaps you might want to sell them again and use the money to buy a rope that is appropriate for top roping.

Billy Uhlhorn wrote:

… I want the abilities of the grigris but don't want to spend money on another belay device. 

I’m not usually someone who gives binary answers but in this case you need a fatter rope or a different belay device. Chose one.

7.9mm ropes are a poor choice for top-roping even with an appropriate device. Thin half ropes stretch a lot under bodyweight so a fall near the start of the climb can easily land the climber back on the ground. Top-roping can result in falls with the rope in contact with the rock, sometimes repeatedly at the same point, so a thin half may not last long. 

This rope will work at a stretch (pun intended) with a more appropriate device. Keep it tight when the climber is close to the ground. The better solution is to use a fatter single rope within the design parameters of the grigri.

Bryce Adamson wrote:

Sounds like your buddy sold you a pair of half ropes. Since you don’t want to use them for their intended purpose, perhaps you might want to sell them again and use the money to buy a rope that is appropriate for top roping.

Or just buy a proper belay device.

Pretty sure it would turn into a shitty ATC at that diameter

A bit of history: once upon a time, before there was Gri-gri2, gri-gri plus, and all the other new gri-gris, there was only the original gri-gri, retroactively christened gri-gri1, after the 2 came out.

The recommended rope diameter on Grigri1 was listed as 10-11mm. The ropes got skinnier long before the gri-gri2 came out. So, for several years, I was using a gri-gri1 to belay on a 9.1mm rope.

I have caught 100s, if not 1000s of lead falls using this combination of device/rope, and have taken many falls with my trusted belayers using this rope/device combo.  I have never dropped my climber, and have never been dropped.

So, I personally would be completely comfortable belaying on a skinny rope using newer gri-Gri’s, especially on top rope. But I would be very choosy about my belayers on this rope/device combo. I have plenty of trusted belayers with whom I would not hesitate to climb in this scenario. But there are a lot more people out there whom I wouldn’t trust to belay me, even if they had a much thicker rope, so YMMV, obviously.

Lena chita wrote:

A bit of history: once upon a time, before there was Gri-gri2, gri-gri plus, and all the other new gri-gris, there was only the original gri-gri, retroactively christened gri-gri1, after the 2 came out.

The recommended rope diameter on Grigri1 was listed as 10-11mm. The ropes got skinnier long before the gri-gri2 came out. So, for several years, I was using a gri-gri1 to belay on a 9.1mm rope.

I have caught 100s, if not 1000s of lead falls using this combination of device/rope, and have taken many falls with my trusted belayers using this rope/device combo.  I have never dropped my climber, and have never been dropped.

So, I personally would be completely comfortable belaying on a skinny rope using newer gri-Gri’s, especially on top rope. But I would be very choosy about my belayers on this rope/device combo. I have plenty of trusted belayers with whom I would not hesitate to climb in this scenario. But there are a lot more people out there whom I wouldn’t trust to belay me, even if they had a much thicker rope, so YMMV, obviously.

In climbing caveats can be killers.

OP your rope is too skinny for your application. The policy of never cutting corners will do you wisely.

If your dead set on using that rope, double it over and use an ATC to belay both strands at once, or use a munter to belay both strands at once.

Skinny skinny dynamic twin rope = dangerously high stretch for loading a single strand.

Tradiban wrote:

In climbing caveats can be killers.

OP your rope is too skinny for your application. The policy of never cutting corners will do you wisely.

You are right. I only skimmed the op, and didn’t realize that OP was thinking of using a rope that wasn’t rated as a single rope. Obviously a bad idea.

I was thinking that he was talking about a skinny single rope, like Beal Opera, 8.5mm. The new gri-gri is rated down to 8.5mm, so the combo should be safe, in experienced hands.

A completely separate question is why OP wants to toprope on a rope this skinny, and whether this is the best approach. But that wasn’t the question, I guess. 

The most likely device-related problem with thin ropes is that lowering will be laborious.  This device (with a hand on the brake strand) is so good at catching falls that lowering becomes a challenge much sooner than catching falls as you go down in diameter.

But if "the abilities of the grigris" in your mind includes catching falls with the belayer knocked out by rockfall, that fails even for some ropes near 9mm (see HardIsEasy videos on youtube)