New Petzl belay device

Jim Tittwrote:

I'll seeif I can extract the information fro a paper I wrote years ago but yes 2 x90° is vastly different to 1x180°, in fact even the seperation between the 90's makes a substantial difference. The Capstan equation is worthless because in a climbing rope the majority of the " friction" is actually generated in the rope resisting bending (the friction between the individual filaments of the rope actually have to slide past each other for it to conform around the object. I built an exact replica of an ATC but using needle roller bearings to demonstrate this for a lecture I gave once.

I am not surprised of all the folks on here you would chime in as having had done tests around this exact scenario.
Would love to see that paper or an abstract if you find it!

I would like to add, I finally got a chance to use the neox a bunch today. Its dreamy. Huge fan of it and very much see it being an awesome LRS / TRS device.

Tommy-Xavier Robillardwrote:

That clicky sound is so annoying when he lifts the "climber" up, I really can't believe nobody talked about this before (unless I'm blind?). I now hope this doesn't actually become the more popular device haha.

The release version of the Neox actually had the clicking sound "fixed"- the initial prototype all the big names/guides/retailers got sent samples of had a much louder clicking noise.

Old lady Hwrote:

I'm currently at City of Rocks, haven't got this out on an actual wall yet, but, it's been in quite a few hands on the ground, and, yeah, it's got some " limitations", as does everything. 

I do think, as do others, that people who are ATC users will enjoy this....

But.

I also think it will be pretty dangerous in the hands of grigri users with bad habits....but those folks are just accidents waiting to happen anyway.

H.

Well, for one, when you lower someone, as soon as their feet touch down, the wheel lock tends to disengage, and there's suddenly 0 friction.

Mr Rogerswrote:

I am not surprised of all the folks on here you would chime in as having had done tests around this exact scenario.
Would love to see that paper or an abstract if you find it!

I would like to add, I finally got a chance to use the neox a bunch today. Its dreamy. Huge fan of it and very much see it being an awesome LRS / TRS device.

You can find it in the last part of this webpage http://www.bolt-products.com/Glue-inBoltDesign.htm

As you can see it's the first part of the bend makes the most effect, the difference between 90° and 180° wrap angle of the rope is quite small so depending on the rope etc maybe only a 20% increase. The rope bending resistance is the dominant force of the friction around a karabiner making between 60 and 70%.

The important thing to know is the energy required to bend the rope is lost (it goes away as heat) so when the rope straightens (which does actually require some energy in itself) and then has to bend again there is another energy input required. As you seperate the two bend radii this amount of energy increases (when they are close together the rope doesn't really straighten out properly) and by experimentation we see that for a normal climbing rope around 10mm karabiners this peaks at a seperation of around 7x rope diameter with an increase of roughly 20% (there are people who insist that having two biners at the top when top-roping reduces the friction, they are completely mistaken). This is the reason that taller tube belay devices like the ATC work better than the more modern flat ones.

Serge Swrote:

1) It's not obvious how much more friction two 90-degree turns give compared to one 180.  https://en.wikipedia.org/wiki/Capstan_equation would actually predict the same friction. 

Setting aside the applicability of the Capstan equation, addressed by others above...

What numbers are you using to come to this conclusion?  e^(μ 2ϕ) ≠ 2 e^(μϕ).  It's approximately true when the product of the angle ϕ and coefficient of friction μ are small but it's not obvious to me that this is the case here.

*caveman noises*

OG LIKE ATC. ATC WORK GOOD ENUFF.

Jokes aside it’s cool to see the physics and math behind the things we take for granted. Now go climb something. 

Mr Rogerswrote:

I am not surprised of all the folks on here you would chime in as having had done tests around this exact scenario.
Would love to see that paper or an abstract if you find it!

I would like to add, I finally got a chance to use the neox a bunch today. Its dreamy. Huge fan of it and very much see it being an awesome LRS / TRS device.

Don’t use it for LRS

Brent Barghan tried it for LRS and found it to be terrible. Dude took 20 LRS whippers for science. The Neox hit the stopper knot every time. He posted to the LRS FB group. 

My first impression of the Neox is that this has been specially made for lead competition.

Like I wonder if the IFSC has a mandate for assisted locking belay devices incoming, and this is for compliance. The pros and wannabe pros who are preferring an ATC belay right now, wanted something different to the Grigri with fast and smooth feeding above all else.

Sam Mwrote:

My first impression of the Neox is that this has been specially made for lead competition.

Like I wonder if the IFSC has a mandate for assisted locking belay devices incoming, and this is for compliance. The pros and wannabe pros who are preferring an ATC belay right now, wanted something different to the Grigri with fast and smooth feeding above all else.

When I was letting people try it out at City of Rocks recently, that included a couple who were involved with team competitions, and that was the first thing they said, "bet this would be great for comp climbing,!".

Part of the REI 4th of July sale 25% off

https://www.rei.com/product/232858/petzl-neox-assisted-blocking-belay-device?redirect-pup=false

The Neox seems to be a better choice for cold/wet conditions wearing gloves & mittens because less finger dexterity is required. Curious to hear from others about partner multi pitch experience. 

I used one for the first time this week. Its pretty neat but sure it felt nessecary. Feeds slack out quicker/easier and feels more like a ATC. Still locks when pulled on quickly like a GriGri but it seemed to take a little more force and not lock as quick (maybe could make falls a little longer). You can top belay with them and my friend said it felt really smooth and easier than an ATC, while also safer. To be honest, I am not sure that I'm sold on it yet. I did not get the feeling it was better than than the GriGri, especially at the price. I did not get to use it long and these were just some quick thoughts. 

Mitchell McAuslanwrote:

You can top belay with them and my friend said it felt really smooth and easier than an ATC, while also safer.

Safer than an ATC for a top belay is objectively inaccurate. Smoother and more convenient, sure, especially for lowering if needed, but an ATC in guide mode belaying has fewer failure modes and is basically hands-free. 

K Gowrote:

Safer than an ATC for a top belay is objectively inaccurate. Smoother and more convenient, sure, especially for lowering if needed, but an ATC in guide mode belaying has fewer failure modes and is basically hands-free. 

Not mention the less readily an abd cams (and neox looks damn near the least) the more the rope will slip through in guide mode

Always makes me cringe when I get up to a belay and my partner is full hands-free on a grigri or similar in "guide mode" configuration lol.  The brake strand tends to be perfectly oriented for slipping through without triggering the cam.

Mitchell McAuslanwrote:

I used one for the first time this week. It’s pretty neat but sure it felt nessecary. Feeds slack out quicker/easier and feels more like a ATC. Still locks when pulled on quickly like a GriGri but it seemed to take a little more force and not lock as quick (maybe could make falls a little longer). You can top belay with them and my friend said it felt really smooth and easier than an ATC, while also safer. To be honest, I am not sure that I'm sold on it yet. I did not get the feeling it was better than than the GriGri, especially at the price. I did not get to use it long and these were just some quick thoughts. 

Use in ‘top belay/guide mode’ seems like the missing feature.  Interesting/cool/not cool that it is getting used that way. 

Interesting point made in the video is the Neox needs about 20kgs of weight for the wheel to lock and for the device to act like a GriGri.

Is it possible that Petzl cannot certify guide mode because a child or pack weighing less than 20kgs is light enough that its weight would not lock the wheel in guide mode and the device would not arrest a fall?

Live Perchedwrote:

Interesting point made in the video is the Neox needs about 20kgs of weight for the wheel to lock and for the device to act like a GriGri.

Is it possible that Petzl cannot certify guide mode because a child or pack weighing less than 20kgs is light enough that its weight would not lock the wheel in guide mode and the device would not arrest a fall?

And how much for the grigri?

Live Perchedwrote:

Is it possible that Petzl cannot certify guide mode because a child or pack weighing less than 20kgs is light enough that its weight would not lock the wheel in guide mode and the device would not arrest a fall?

Petzl approves the Neox for guide mode.