Improving safety margins of the petzl adjust through improved rope choice

We all know nobody likes the original rope in the petzl adjust, ironically, it's quite difficult to adjust even when not weighted. As such many choose to replace it with accessory cord or half ropes. This replacement of cord comes I feel as a bit of unknown as after all we don't have a great idea how the adjust fails, we just assume it will slip. 

This is the result my friend had from a fall test using an old gen edelrid rap line with the adjust, this was read to happen at just 3.4kn. What's happened here?

 I'd guess the rap line has a weak sheath and most of the strength is found in the core causing quick failure of the sheath. If this is the case any cord or rope with a weak sheath may have a similar failure mod. Accessory cords have no listed sheath percentage, halfs and twins generally have a pretty low sheath percentage. 

So, solving this problem, does anyone know of any cords or ropes that might be particularly suitable to avoid this failure mode? I'm thinking super strong sheaths, maybe dyneema if it can be made to not slip. If anyone has any large diameter dyneema cord I'd be interested to see if that works. 

Yes 6mm accessory cord can work even taking high FF daisy falls, but, it would be foolish to say cord is cord and it would be better to find a single product optimised for this use. 

that guy named seb wrote:

We all know nobody likes the original rope in the petzl adjust, ironically, it's quite difficult to adjust even when not weighted. As such many choose to replace it with accessory cord or half ropes. This replacement of cord comes I feel as a bit of unknown as after all we don't have a great idea how the adjust fails, we just assume it will slip. 

Maybe I’m weird, but I like my stock Petz’s Adjust. I’m an early adopter and have been using it since 2017. It lives on my harness. I converted a few partners. Never slipped on me.  I don’t have strong hands, but can manage to adjust it when I need to. 

I have looked into thinner cord just because I’m a weight weenie, but never liked the knot finish of any homegrown solutions, and thought it’s not worth my effort to mod. 

Mei pronounced as May wrote:

Maybe I’m weird, but I like my stock Petz’s Adjust. I’m an early adopter and have been using it since 2017. It lives on my harness. I converted a few partners. Never slipped on me.  I don’t have strong hands, but can manage to adjust it when I need to. 

I have looked into thinner cord just because I’m a weight weenie, but never liked the knot finish of any homegrown solutions, and thought it’s not worth my effort to mod. 

The single largest issue with the stock adjust is the lack of length for aid climbing, if I've top stepped on a piece and want to daisy bounce the next piece I need to be way down on my previous ladder. If all you want it for is as a PAS then yeah there is no great benefit, but as a positioning device and a tool for aid climbing, in its stock form, it leaves a lot to be desired. 

Don't be afraid of the knot termination it's what edelrid does. 

that guy named seb wrote:

The single largest issue with the stock adjust is the lack of length for aid climbing, if I've top stepped on a piece and want to daisy bounce the next piece I need to be way down on my previous ladder. If all you want it for is as a PAS then yeah there is no great benefit, but as a positioning device and a tool for aid climbing, in its stock form, it leaves a lot to be desired. 

Don't be afraid of the knot termination it's what edelrid does. 

Pretty sure the Connect Adjust is meant for PAS. For aid climbing, there’s Evolv Adjust. The length of the two legs is so long that I paid a cobbler to shorten them with a neat “factory”finish. My arms are short and I don’t do hard aid, so I don’t need to carry the extra length with me.

I’m not afraid of the knot finish. Every homegrown knot finish I’ve seen is bulky and can more easily get caught. Just annoying in general. 

I’ve been using the Maxim 5mm tech cord for a few years now and like it. You get some concerned looks from others occasionally due to its size but it’s around 21kN (4700lbf), extremely abrasion resistant and nearly impossible to cut due to it being 90% technora. All of the considerations of a static pas apply still of course 

Seb,
have you ever used the evolve adjust?
Thats was made for aid climbing. Smaller metal toggles, and very long rope. It uses the 7.7mm PASO guide rope as the rope for it.

I would use this line instead of the rap line.
6mm 64% sheath https://www.bluewaterropes.com/product/6mm-technora-hybrid-searchline/
7.5mm 58% sheath https://www.bluewaterropes.com/product/7-5mm-hybrid-escape-rope/

Tanner James wrote:

I’ve been using the Maxim 5mm tech cord for a few years now and like it. You get some concerned looks from others occasionally due to its size but it’s around 21kN (4700lbf), extremely abrasion resistant and nearly impossible to cut due to it being 90% technora. All of the considerations of a static pas apply still of course 

The Polyester sheath is unlikely to be particularly resistant to the failure mode shown in the original post. 

Mr Rogers I have both variations the hardwear is the same. 

Your evolve toggles are the same size as the connect?!
Mine are deffintily smaller than the regular connect toggle, but mine is also the very first version of the connect.... there is no way the larger rope of the connect would fit throught the evolve toggles I have.

5mm Tech cord seems good on paper for the strenght but i find it too stiff and not that smooth, 7-8mm soft supple accessory cord is smoother to me than 5mm tech cord.  Ive seen a few people put some 6mm purline, which is full dyneema, seems super smooth and actually stronger than 8mm accesory cord... just wondering if its not too slippery, anyone else using purline ?! 

J D wrote:

5mm Tech cord seems good on paper for the strenght but i find it too stiff and not that smooth, 7-8mm soft supple accessory cord is smoother to me than 5mm tech cord.  Ive seen a few people put some 6mm purline, which is full dyneema, seems super smooth and actually stronger than 8mm accesory cord... just wondering if its not too slippery, anyone else using purline ?! 

Colin Haley uses purline in his connect adjust

that guy named seb wrote:

The single largest issue with the stock adjust is the lack of length for aid climbing...

That does not seem to align with the title of the thread. Anyway, I feel that none of the mods are about "improving safety margins". I've seen plenty of people put smaller cords on their Connect Adjust, but that's for weight saving and allegedly "easier" adjustments. I think it is in the "personal preference" territory. 

I might be using up my quota of replies in a thread for the day, but that's enough of my defendence of this product. Have a good day to all!

Mei pronounced as May wrote:

That does not seem to align with the title of the thread. Anyway, I feel that none of the mods are about "improving safety margins". I've seen plenty of people put smaller cords on their Connect Adjust, but that's for weight saving and allegedly "easier" adjustments. I think it is in the "personal preference" territory. 

You seem to misunderstand the point of the thread, the point of this thread is to draw attention to a potential failure mode that has previously gone undressed by the numerous people who decide to switch out their cord on the adjust and crowd source options for more suitable cords. If you're happy with your stock cord that's great, good for you. But many aren't, and it would be good to improve the safety for people who do want to mod their adjust. Considering there is a multi page Thread on moded adjust set ups this is quite relevant to a lot of people. 

Regarding the pur line, great option, does anyone know if it'll slip at high loads? 

For a stronger sheath, you need to have Technora blended in.  Dyneema is less common on sheaths because it's slippery, where Technora grips nice.

Marlow makes 6 and 8mm (and more, obviously) diameters of Dyneema-core, Technora/polyester covered line which would be perfect.  Their MGP Furler line (a different braid pattern of Vectran and polyester) is also good in devices like that (I've used it on my Kong Slide), and has the option of polypro or dyneema core.  Excel Control is similar, but with Technora/polyester.

Perhaps someone makes stretchy nylon rope with a tech/poly cover, but I don't know of any.  There's also exotic blends with different amounts and combinations of Technora, Dyneema, Polyester, Kevlar, and PBO covers, but those get pricey real fast.

I think there are three main qualities that we are looking for to improve safety:

1. Full strength (won't break in FF2 fall)

2. Rope stretch (that same FF2 fall won't have an impact force high enough to injure you)

3. Slipperiness (will the rope slide through the device at a certain force? this will reduce impact force, along with 2.)

Then there is ease of use (is it easy to pull through the device). This might be more of an aid climber thing but the ideal rope would be very easy to extend and shorten.

HowNot2 did a little testing on this, but no testing with half ropes, cord, purline, or any of the other popular things people are using.

Seb, regarding the specific failure mode in your post: isn't the edelrid rap line designed intentionally to have the sheath break at a certain force, to reveal the dynamic core? I thought that was an intentional feature.

Yukon Cornelius wrote:

I think there are three main qualities that we are looking for to improve safety:

1. Full strength (won't break in FF2 fall)

2. Rope stretch (that same FF2 fall won't have an impact force high enough to injure you)

3. Slipperiness (will the rope slide through the device at a certain force? this will reduce impact force, along with 2.)

Then there is ease of use (is it easy to pull through the device). This might be more of an aid climber thing but the ideal rope would be very easy to extend and shorten.

HowNot2 did a little testing on this, but no testing with half ropes, cord, purline, or any of the other popular things people are using.

I think 2 and 3 may be more or less the same, ultimately whether it slips or stretches the result is the same, reduced impact. Slipping would probably be better than having a dynamic cord as daisy testing benefits from a static cord. 

Seb, regarding the specific failure mode in your post: isn't the edelrid rap line designed intentionally to have the sheath break at a certain force, to reveal the dynamic core? I thought that was an intentional feature.

It is made to tear in a fall, however I'd expect this to happen in normal scenarios at the first bend in the knot. The fact that it failed in the adjust would suggest the adjust may exert a good deal of pinching force on the rope and as such may be bad for ropes with thin sheaths (such as a lightweight half rope). It also broke at 3.4kn, I don't know what load it was designed to break at, but the new rad line saw 7.22kn in this video and didn't break in the Edelrid pinch or the knot.

This failure mode isn't particularly uncommon in ropes. If we look at various rope clamps (such as the ISC rocker or Edelrid fuse) you often get failure of the sheath in climbing ropes, they simply aren't anywhere near as sturdy as what you find in an 11 or 12mm static that they are designed to be used with. 

Really good point! I honestly hadn't considered that.

Relevant HowNot2 video 

3:50 - FF2 on stock evolve adjust (not fully extended) has an impact force of 5kn and the rope slips a bit.

6:35 - stock evolve adjust slips at about 3kn in a slow pull, with a peak force around 5kn.

This has definitely led me to believe that the device would slip under high force, like a grigri, rather than sheath a rope, like a rope clamp. I wonder if we could replicate that failure mode with any other ropes.

Ben Zartman wrote:

For a stronger sheath, you need to have Technora blended in.  Dyneema is less common on sheaths because it's slippery, where Technora grips nice.

Marlow makes 6 and 8mm (and more, obviously) diameters of Dyneema-core, Technora/polyester covered line which would be perfect.  Their MGP Furler line (a different braid pattern of Vectran and polyester) is also good in devices like that (I've used it on my Kong Slide), and has the option of polypro or dyneema core.  Excel Control is similar, but with Technora/polyester.

Perhaps someone makes stretchy nylon rope with a tech/poly cover, but I don't know of any.  There's also exotic blends with different amounts and combinations of Technora, Dyneema, Polyester, Kevlar, and PBO covers, but those get pricey real fast.

Edlerid swift protect fits this category, but not in diameter good for this application IMO.
Also the bluewater rope(s) I linked above are a tech/poly sheath and nylon core, so seemigly fit the catatgory you present well @ 6% stretch at 300lbs, 11% @1000. So pretty good dynamic properties at 4.5kn So not super dynamic, but not LSK either.
The 6mm only hits 11kn, but the 7.5mm is 19kn. I would trust either as a PAS line, but some would want the higher safety margin of the 7.5 for sure.

J D wrote:

5mm Tech cord seems good on paper for the strenght but i find it too stiff and not that smooth, 7-8mm soft supple accessory cord is smoother to me than 5mm tech cord.  Ive seen a few people put some 6mm purline, which is full dyneema, seems super smooth and actually stronger than 8mm accesory cord... just wondering if its not too slippery, anyone else using purline ?! 

I've been using Purline with good results. It can occasionally twist around in the metal piece and then won't lock, but flicking it around quickly fixes it. My biggest concern is how flat the purline becomes after weighting it. I can always get it back to being spherical, but it is definitely compromising it's lifetime. 

https://www.westmarine.com/new-england-ropes-3-8inch-regatta-polyester-single-braid-sold-by-the-foot-405894.html?utm_medium=cpc&utm_source=google&utm_campaign=%5BADL%5D%5BPLA%5D%20Most%20Categories&gad_source=1&gad_campaignid=21019856781&gbraid=0AAAAAD_lEeroI7mHnk9x2oJCEqJG8jaE6&gclid=Cj0KCQjw_dbABhC5ARIsAAh2Z-T4GT59z6dyVqppo-Mq4shMwkRt0gaehZuC3DT0bF1X8CECOqyWsIQaAhMUEALw_wcB

Splices easily, no bulky knots, and easily inspected. The 5/16” has a 13.3 kN break strength, with smooth sliding.

Brocky wrote:

https://www.westmarine.com/new-england-ropes-3-8inch-regatta-polyester-single-braid-sold-by-the-foot-405894.html?utm_medium=cpc&utm_source=google&utm_campaign=%5BADL%5D%5BPLA%5D%20Most%20Categories&gad_source=1&gad_campaignid=21019856781&gbraid=0AAAAAD_lEeroI7mHnk9x2oJCEqJG8jaE6&gclid=Cj0KCQjw_dbABhC5ARIsAAh2Z-T4GT59z6dyVqppo-Mq4shMwkRt0gaehZuC3DT0bF1X8CECOqyWsIQaAhMUEALw_wcB

Splices easily, no bulky knots, and easily inspected. The 5/16” has a 13.3 kN break strength, with smooth sliding.

Regatta braid fattens up significantly with age--I use it alot on boats.  But their Salsa, same construction but with dyneema blended in, stays more cross-sectionally stable.  Neither is remarkably chafe resistant, though, with those large picks.

Seb, is there any chance we could get your friend to do some fall tests and/or slow pull tests with some other cords? Personally, I would be most interested in results for 7mm cord, purline, and that edelrid half rope people like to use. I would pitch in for materials if they are down!