Me and two friends have an upcoming trip to Rainier and I am looking for a glacier cord. I came across a used rope for a solid deal that has only been used once. It is a Sterling 8.4mm x 60M dry treated rope. Some other specs noted are Dynamic Elongation: 31.60%, Impact Force: 6.5 kN, Static Elongation: 11.00%, UIAA Falls: 6, and Weight: 45 g/M.

My main question is regarding the width. Some feedback I have gotten suggests should be using 9-10mm for a single so I am hesitant to pick this up. Would 8.4 do the trick as a single rope or is this the type of rope that needs to be doubled?

That should be a great rope for glacier travel, especially as a fall on a glacier would typically have much less force than a fall rock climbing. One thing to pay attention to is your prussiks on a smaller diameter rope. I think most people use 5mm rather than 6mm for this, and probably 3 wraps for it to grip well - practice beforehand). Z-pulley as well. Have a great trip.

On further thought, personally I'd probably not get a used rope unless you really were confident about how it was taken care of, etc.

I'd climb on it.

But width aside, you should also pay attention to the dry treatment. Is it sheath only or sheath + core (double-dry)? Took a well used single-dry rope up a peak once and I won't make that mistake again. after dragging through the snow all day, it probably weighed 3x what it did at the beginning. Sucked to carry out.

Thanks for the advice all. Cannot wait for this trip!

Strength isn't a big factor for glacier use. The biggest reason I see to use a fatter cord is dragging yourself out of a crevasse - make sure your jugging system will work on a wet, half-frozen skinny rope.

Your best bet for each type would be:

knot: 4mm cord in a Klemheist,
full-size ascender: BD nForce
micro-ascender: Wild Country Ropeman Mk II

Hanging in a crevasse is not an ideal time to figure out that you can't jug with what you have on you. As much as jugging sucks for you, it's not nearly as bad as hauling is for your partners.

would u really trust your life jugging up a rope inside of crevasse on 4mm cordage?

i guess, i have always found it odd how much we all make sure we have the strongest spectra runners and 8mm cordage anchors, and then when we actually intensionally start hauling or jugging up a rope, people seem to have no trouble trusting a teeny 4mm cord with their life.

i wouldnt trust hauling my pack with 4mm cordage if were in a crevasse or anywhere in the mtns, let alone my life.... but i guess its fine for my camera and water bottle.

I would much rather ascend a rope with 4mm cord than slide back down on 6mm that won't lock on a skinny, icy rope.

I would also tie-in short every meter or two. Just in case.

A doubled 4mm cord is good for over 6kN. People routinely place nuts and cams rated for 6kN and expect them to catch a leader fall. I understand that the worry is sliding and wearing through - but I would use new cords each trip, and a 4mm is much less likely to slip than a fatter one - and I'd rather have a skinny cord that doesn't slip vs. a fat one that does.

But, I use a Ropeman and a Tibloc instead.

IMO 4mm is too thin. Go with 6mm and just use an extra wrap. Remember that if you use your prusik loops for setting up a haul system the forces can be multiplied.

We take 5mm cords when we use an 8.1 mm rope for glacier travel. The 6mm cords we have around here are too stiff to lock on to the rope well. The 5s we have are nice and supple.

Of course we don't use such a thin rope if we expect big crevasse falls and when we're just a two-person team we really expect the fallen climber to prussik out on their own using their 5mms.