cordelette size (width)

[layton]

what's the narrowest diameter perlon you'd use for your anchor? (note: talking perlon, not super tech cord fancy stuff)

 

I'd say 6mm for most, 7mm for more serious routes. never 5mm.

[genepires]

for defense of the 6mm cord

According ot the pezl website, the most force that could be put on the anchor is 9KN which is fall factor 2 right on the anchor. A KN is roughly 225 lbs so we are looking at needing to hold 2025 lbs. If you have two legs in the anchor equally loaded then each leg needs to hold 1013 lbs. Each leg is made of a loop of cord so each piece of cord needs to hold half of that again, 506 lbs.

 

6mm cord is rated to around 1700 lbs, well above the force needed above. It is rated to three times that force.

 

This does not take into account the weakness of the knot and less than perfect equalization. I am sure there will be other factors not realized yet too.

 

With that thought, I still use sewn runners on harder climbs but feel fine with 6mm in the mountains were fall factor 2 are next to impossible.

[layton]

i went into a gear shop to buy some 5.5 mm "tech cord" rated to like 5000 lbs and was about to be given regular 5mm perlon instead. i said no, that's not the same thing, so we looked at the rating of the 5mm perlon...9kn. I said no thanks, he insisted it was safe, some chestbutting ensued, and I bought the tech cord elsewhere.

[corvallisclimb]

for alpine i use only

[Billygoat]

Nice! A Madrock Quick Draw Thong (tm.)

 

Wherever did you get that?!

 

 

 

 

 

Just so we don't totally shit on your thread Mike:

 

What is the main consideration besides being right where the other guy may be wrong? Is it the weight or volume of 6mm perlon vs. 5.5mm tech line or 5mm perlon? It seems to me that it would be better to leave your toothbrush behind and go with the 6mm (I don't know shit about the "tech" line). I have read and heard both 6mm or 7mm perlon is the standard, depends on who is spraying. I use 6mm. I do carry a handy 15' lengh of 5mm around wih me for lashing stuff or making prussics, whatever, but I'm not carrying a machete either so I can afford a few ounces

[catbirdseat]

Part of the issue is that the store employee should respect the customer and either give him what he wants or simply say sorry, rather than try to substitute and inferior product.

[layton]

maybe they confused tech cord with perlon.

[Cobra_Commander]

I think 6mm perlon is perfectly adequate for the job, and 7mm can be unwieldy to tie three legs of a cordolette together or to have hanging on your harness.

 

Just to point out, Gene's calculations above assume two anchor points perfectly above the power point, with zero angulation, which is essentially never the case. The forces on each leg will be considerably greater as these points move apart.

 

It's generally a good idea to have a healthy safety margin between the material breaking strength and the maximum load you anticipate, rather than simply counting on the rated strength.

 

I like to use a general rule of thumb that any knot in a cord reduces the strength by 1/3rd.

[olyclimber]

for alpine i use only

 

 

I haven't heard of these Pine Cone biners, but they look good.

[Pinecone]

I agree!