Neox for LRS and TRS

 

 Neox for Seamless LRS and TRS

A final progress update and abandonment of the project

There was a lot of discussion anticipating the release of the Neox in relation to LRS. Since its release, there has been an almost widespread claim of it unsuitability as people obtained them and started using them. I was not one of them. I saw a lot of potential for it being a better LRS/TRS device. Most of the general concern re the Neox as a rope solo device stemmed from how free-flowing the rope is when used according to Petzl's instructions and how strong the cam-arm spring is. This, and some initial tests and statements by "test pilots" view that it would be difficult for the wheel to lock-up and stop a fall without a hand on the rope. 

However, I saw other possibilities for overcoming those concerns through four modifications: removing the cam arm spring; doing a partial tab grind to straighten out the rope path a bit to further reduce friction but still preventing the rope from getting caught underneath the cam arm; coming up with alternative way to add back in the desired amount of cam-arm tension for LRS and being able to remove that tension at will for TRS; and, finally rigging it in a novel manner so the Neox is in a normal hanging belay orientation, but held up by a chest harness which would make it free to orient itself for a normal or headfirst fall and still lock-up.

After removing the spring, doing a partial grind of the rope tab, and starting work on some additional mods to make cam arm tension adjustable and removable, along with some additional mods and testing, I felt that it could theoretically be the "holy grail" that we've all wanted. And, be able to do all this with one device without removing from it from the chest harness. I still believe it might be possible, though at this point, I'm stopping further modification and development of it.

Sooo...why am I stopping development of that wonderful possibility?! There are five main reasons:

1) It would require so much modification that 99% of LRSers wouldn't (and shouldn't) do the modifications. 2) TRSing with it will never be as good as some of the other methods out there; 2) While for LRS it could rival a heavily modded GG+ for ease of feed and lock-up - the Neox is larger, heavier,  more expensive and more complicated. 3) With the spring removed, and without a hand on the free-end of the rope it locks up quick. However, because there is no hand to initiate lock-up, the wheel can tend rotate more than it normally would because of of its orientation. This is evidenced by a clickedy-clack sound (the wheel-stops, start engaging hitting each other until it locks up positively). When used for normal belaying, the orientation of the Neox is 90 deg to the angle of rope pull which means a max of half-rotation before the wheel stops and engages. Because of the different orientation for both LRS and TRS the angles are different and the stops tend to hit and rub and go clickety-clack before locking up. To be clear - it DOES lock up very positively without the spring, however I wonder about the extra wear on these small stops inside the wheel. And, 4) the Neox is basically a "black box" - in that you can't examine the condition and wear of the stops inside the wheel/hub combo. I'm sure Petzl has created a robust device. However, they didn't create it for the unique orientations that are used for rope soloing. So without any means to monitor the wear of the stops, it is a huge negative for me. (The actual insides of the Neox wheel/hub combo can be observed in Beta Climber's video (who makes the same points, starting at minute mark 4:20). Lastly, 5) I had some Revo like repetitive lock/unlock issues while lowering my wife when testing it in the gym. I doubt this would ever happen with smaller ropes and heavier climbers rapping with it. But, still...

So there you have it. Nice idea...but for me, not worth further time/effort in sorting things out and testing. I actually didn't get to the final stage of mods before I decided to "pull the plug" on finishing up the final modifications and testing.

Sooo...the holy grail is still elusive. I believe it will eventually come in the future - either as a mod to an existing device or maybe as a ground-up design. Here's the rub though - we all want an all-in-one device that's "best-in-class" for each of the functions it needs to perform and we want it to be compact and lightweight. THAT, is a tall order to fill and we could be waiting quite a while for that. Of course I could be wrong because of all the increased interest in rope soloing. Until then we have to make compromises in function/performance and wisely assess the degree of risk we're willing to take.

Photos documenting some of what I did

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Neox - Removing the Spring and other Mods

The following are some photos from the mods and experiments I've done. This is just to document what's been done. This project has been abandoned. See previous post

If I were to do it again, I'd use a drill press and drill a series of 1/16" holes around the circumference of the axle and just deep enough to go through the plastic cover, then cut through and connect them with an Xacto knife. The Dremel bit that I used was actually difficult to use freehand. The cover is easily removed once circumference cut is made through it and by unscrewing the phillips head screw in the corner. 

Below are further mods and experiments with ground rope tab and attachment configuration for HUR to chest harness allowing normal belay orientation which with the right tension on the cam arm allows it to feed for LRS and still lock-up for an inverted fall

Not shown are my experiments with adding back in some tension on the cam arm for LRS feed. I experimented with elastic cord that is adjustable and easily removable based on a concept by Derek Avrill, as well as with magnets that could be adjusted for tension or could be dialed out by pivoting. The magnet release experiments are still ongoing in relation to a springless GG 2019.

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 GG Lever Shortening

I consider this modification non-essential. It is something that I have done off and on GG's that I have modified for LRS. The main practical potential is to prevent the end of the handle from getting tangled up or obstructed in some way that it would prevent the GG from locking-up. This is extremely unlikely and one of the last mods I do on a GG for LRS, if at all. The handle does not need to be as long as it is, so it's really not an issue to shorten it. I have fairly small thin fingers so shortening it still allows me plenty of control when rapping.

What I do: 

Cut to the desired length by trimming ~3/8" - 1/2". I shorten it so that 3 fingers can still fit on the handle

Fill open "I" beam exposed with JB weld for 1/4" to 1/2" 

Grind/sand to final shape approximately the shape of the original profile of the handle.

I've seen some people shorten it a lot more and many don't bother filling and shaping the end of the exposed 'I' beam handle with epoxy. I consider that step more aesthetic. However, it does make it smoother, more comfortable and adds a bit of strength - not that it's an issue.

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 Electronic Speed Activated Release

This is only a proposal. It's what I see as desirable characteristics of an electronic release of the GG from the HUR position allowing it to pivot to the USD position for lockup in an inverted/headfirst fall. This is outside my knowledge and skill set to design and experiment with something like this. However, I outline what I would personally consider desirable for a widget that would perform this function. It seems like it could be made with off-the shelf parts.

While I've labeled it a 'gravity' release, it would be more accurate call it a speed/acceleration sensing device.  There are micro circuits available that are designed to sense motion. I would see that as the core around which a device could be built.  The challenge would be to design it small enough and light enough to be practical.

Design criteria:

• Small and lightweight
• Based on a micro accelerometer circuit
• Powered by a watch or AAA sized battery
• A micro push/pull solenoid used to release GG HUR attachment loop
• Device could be an all-in one unit (if small enough). Or, the sensing unit could be remote (carried in climbers pocket) which signalled the micro-solenoid trigger located between the GG and Chest harness.
• Adjustable sensitivity, or a circuit that was 'tuned' to only actuate only with the movement of a fall

The main advantage to something like this, would be that it could release the GG HUR connection before there was ever any tension on the rope from the fall and it could also sense a fall in any direction. Therefore, as soon as the rope became taught, the GG would be free to be pulled/pivot to the relative USD orientation allowing the earliest possible lock-up with a HUR setup. This would be a major advantage over the totally mechanical force actuated releases.

Given today's technology, it seems like it could be a relatively straight forward project (said by the Electronically ignorant tinkerer 😏).

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 Introduction to GriGri Modifications

It amazes me that the GG has received so much favor and attention as a possible candidate for a lead rope solo (LRS) device, when, in it's basic unmodified form it is mediocre at best. There are other devices that will feed, lock-up, and are more versatile than a Grigri. And, with less modification, can do everything the Grigri does in for LRS, and in addition can effectively be used for top rope soloing (TRS) and has fewer moving parts. See my posts on the Trango Vergo for LRS and TRS.

However, the Grigri has been available, updated, widely available, and used longer than any other device and has proven reliable, both as a belay device and as a LRS device. It is relatively simple (see photo below of a disassembled GG 2, which is basically the same as all Grigris), and with various mods, it can be a good LRS device (though as mentioned above it is deficient as a TRS device).

This index and linked posts will cover the HUR (Held Up Right) position of the Grigri. It should be noted that the GG can also be used in the USD (Upside Down) position without any modification whatsoever. However, that method can be super sensitive to rope size and have delayed high-clip lock-ups and/or short roping yourself when feeding or clipping pro. The USD position will not be discussed on my blog as there are plenty of materials out there and I also consider it inferior to the HUR. The main exception (and a big one), is that it will likely not catch a headfirst fall in the HUR postion. Thus a reliable backup and other mtigations are necessary. 

1. Grigri chest harness connections to hold in HUR position
2. Modifications to harness attachment to help GG pivot to an USD position for inverted falls
3. Spring modifications to allow easier lockup
4. Rop tab and other modifications that help promote smooth rope feed

The index has basically been organized according to that scheme

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New Rope Finger for (GG+)

New Rope Tab (GG+) - 'The Finger'

When the stock rope tab is ground off a GG+ or a GG2019 to make the rope flow better, it opens the possibility of the rope getting caught underneath the cam arm during a fall and possibly severing the rope. I have not heard of this happening so far. However, it only needs to happen once which could lead to death or serious injury very real possibility. 

Making a new rope tab finger can protect from this happening and virtually make it impossible for the rope to get caught behind the cam arm.  This idea harkens back to the GG2 which had the rope tab on the pivoting cover instead of the cam arm. This resurrects that concept but places it in a position that allows the rope a free flowing path for HUR position so that feed is super smooth and eliminates the danger of a cam arm with the rope tab being ground off.

Note: the GG+ shown in the photos below also has the cam arm fillet mod done on it. Both are probably not needed. If done right I think it's more an either/or situation but having both certainly is 'safe'. If I were going to do just one, I'd probably just do The Finger mod.

Materials I used:
1/8" aluminum rod; stainless tube - 5mm OD 0.4mm wall thickness; 2-part steel epoxy

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 Epoxy Putty Fillet

This pertains only to the GG+ that has the rope tab on the cam arm removed (could also be done on the GG 2019 but I don't recommend because of the strong spring cam arm spring). The major reason for the possibility of the rope getting caught behind the cam arm, is two-fold: 1) The cam arm forms an stepped edge, and, 2) the notch that is formed where the body and cam arm come together. 

Both of these could allow the rope to get pulled under the cam arm which has an edge and could sever the rope. While I have not heard of it actually happening, it seems to me to be a very real possibility. It’s not too difficult to simulate a sideways fall where the rope can fairly easily be forced under the cam arm which has a fairly sharp back side. 

One of the ways to mitigate that concern is to use a two-part epoxy putty and form a fillet that smooths out the difference in height and also fills in the notch so the rope cannot be caught and pulled underneath the cam.

This was an initial try where I just smoothed and leveled the difference in height between the body and cam arm but didn't fill in the notch. While this works fine, the rope can still get pulled behind the cam arm due to the "notch" still being there. The next try and extended the fillet so that it both leveled the body to the cam arm and extended it to fill the notch. See the first photo for end result.

Here's the steps that I used:

1) First I trimmed plastic spine about 3/8”-1/2” to give the putty enough of the back plate to stick well to and provide support. Then I wrapped the cam arm in cling wrap so the epoxy wouldn't stick to it. I lightly roughed up the finish with emory paper where the epoxy was to stick and cleaned with alcohol and let it dry before applying the epoxy putty.

2) The putty was kneaded for 5 minutes (as per instructions) then was molded by hand to as close to final shape as possible. I had to work quickly because it hardens within 5 minutes. With the epoxy putty I used it could be used with water to help smooth it.

3) After 24-48 hours, I filed, ground, and shaped it to final form - then smoothed it using successive finer grades of emory paper. This was tedious but I’m happy with the results.

 

 

 The end result is a nice smooth fillet that allows the rope to flow smoothly around the cam and out the bottom with the round stock 'biner acting as an additional bearing surface. This shows an old retired 'biner and is not the actual one I use, which is a DMM Ceros Locksafe.

Here's another set of photos showing another modded GG+:

First photo is after rough shaping. The rest of the photos are after sanding, shaping and polishing the dried putty from 2020-1000 grit emory paper.

Unknown... How long the epoxy will last before wearing down??? I used a two part epoxy steel putty that is strong and should wear fairly well. It will likely depend upon how often it is used and how clean the rope is. If it started wearing enough to cause issues, it would be easy enough to patch with additional epoxy putty. 

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 Grigri rope tab modifications: intro and warning

Modifying or removing the rope tab on a GG219/GG+ is an extreme measure used to improve rope feed on lead. If done right it can make for extremely easy and efficient rope feed. It drastically reduces the friction of the rope going through the GG by straightening out the rope path. With the stock GG the rope path takes an “S” bend which is the source of the friction. The rope friction can be reduced by using a smaller diameter rope. However it will never be as nice as a GG with a removed or modified rope tab.

When the rope tab is removed it will require additional steps to prevent back-feeding on the live rope since it pulls through the GG easier. There are lots of techniques and widgets/gizmos for managing this, but that is beyond the scope of this blog post.

WARNING: There are dangerous and significant downsides of removing or modifying the rope tab

 

1). It is tricky to do and should only be done by a competent person/a machine shop. It’s possible to ruin the GG in the process and if there are sharp edges it can increase rope wear and/or cut the rope. I have always done the mods myself as I feel competent in making changes. However, I would think that a machine shop could easily mill off the tab and do an excellent job of it. 

2). If the rope tab is completely removed, you run the risk of the rope getting caught behind the tab (especially with smaller diameter ropes) and the back of the cam arm acting like a knife. IMO, this should NEVER be done…UNLESS there is some form of mitigation (see main outline of GG modifications). My recommendation is not to cut the rope tab unless you're willing to make a further modification to protect the rope from getting from getting pulled under the cam arm. (see outline for possible ways to prevent this.

3). When there is an inverted fall, with a stock rope tab, the rope path and extra friction is more likely to cause the GG to pivot 90 deg when/if the tension on the chest harness connection goes weightless. This causes the GG to pivot to an USD position which can help is lockup in headfirst falls. This ability is removed or lessened when the tab is removed. This is another reason why it is SO important for there to be a reliable backup and/or trigger for the Grigri - especially a modified GG.

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