UKC

Whilst we all happily clip wired nuts with quickdraws, extending cams by clipping a quickdraw to the thumbloop seems to be advised against in some quarters. Is this because of a higher risk of failure or deformation of the wire? The wire on most cams seems to be thicker than on most nuts.

In reply to cragtyke:

I've never heard this, although my cams have slings which I clip either with a draw or just the racking krab depending on whether it needs to be extended etc.

What would be the alternative, if your cams didn't have slings? Clip the rope straight to the wire on the cam? Seems like a guaranteed way to make your cam walk...

Where did you see this advice, just out of curiosity?

In reply to mcawle:

I think it may have been on an old thread about reslinging camalots, where the loading of the wide sling they use was said to be preferable to the narrower loading of a krab.?

In reply to cragtyke:

They were probably referring back to this article:

https://www.blackdiamondequipment.com/en/experience-story?cid=qc-labresling...

In reply to spenser:

Yes, something like that, thanks. Interesting that Wild Country friends which use the extendable thin slings are rated at 10kn .

In reply to cragtyke:

If something gets deformed holding a fall, then well done, good and faithful servant.

In reply to cragtyke:

I don't think its that big a deal, I do it all the time. The gear is tested well and I don't think any of them will fail easily. I have also never heard of such a thing. just remember that gear never really breaks even if you abuse the hell out of them.

In reply to beanieman:

If you clip into the thumb loop you run the risk of ruining your cams and its considered bad practice because of this, you can look up QC labs by black diamond they test all sorts of things and things do fail when improperly used. By clipping directly into the thumb loop you could be putting extra stress onto the swage or cause the cable to fray within the plastic protector. And to counter your claim that "gear never breaks even when you abuse the hell out of it" it does break and has broken many times perhaps looking at the failures of climbing kit on QC labs might be an eye opener. Care should be taken with all kit and it should be given a once over after every fall and periodically inspected which if your clipping into the thumb would probably spell the end for that cam after one moderate fall.

In reply to mff513:

I was under the impression that the problem was something along the lines of cams with thumb loops use a wide sling/dogbone because anything narrower will eat in to the metal loop and permanently deform it. there's articles about it somewhere, probably by BD? if you clip a wire thumb loop and take a whanger on it you won't be able to unbend the loop to what it used to look like. I dont *think* it will break but it wont be very nice for your expensive cams. 

I would not clip the thumb loop on BD cams although I dont really see what choice you have (but I dont use these cams so have no real idea/experience). DMM cams on the other hand you can clip the sling extended or not no problem. There is no thumb loop per se its the metal head of the cam.

In reply to cragtyke:

Ooh I see. I have never used cams with thumb loops. I guess they all have a length of sling for clipping even if it's not extendable. Never mind me!

In reply to beanieman:

What experience and/or research makes you pronounce this with such certainty? 

In reply to nniff:

As long at it's not you.

In reply to krikoman:

Touché!

In reply to George_Surf:

Yeah i read that too you can basically pinch the sling and cause it to snap i forgot to put that in, all black diamond cams come with a very wide nylon sling to avoid this happening. Surprisingly I think if I recall the metal cable inside the thumb loop will snap before thin cord or a carabiner breaks.

In reply to cragtyke: nearly all cables used in this sort of thumploop at 4mm galvainsed 7x7 wire rope. The kinking issue comes from sling of any type folding and crushing down in diameter to form a very tight bending radius. The radius a sling produces is substantially smaller than a carabiner which is typically 10mm or larger diameter at the apex of the carabiners upper “basket”. In addition, these units when tested (if tested in a proof loading machine) will be tested using steel pins through the thumbloop typically of around 10-12mm diameter. I really don’t know under what circumstances you could produce as harsh a kink as with a sling. Especially an extendable sling. The reason the WC units are rated at 10kN for extended sling mode and 12kN for retracted sling mode is precisely because of this pinching action. Infact the 10kN rating if memory serves correctly is because the wire deforms permanently beyond this load, not because it breaks at that point. 

In reply to beardy mike:

Thanks for that Mike, it pretty much confirms what I thought was the case.