Those Petzl pulleys without the metal sides

[passward]

Anybody have any experience with the Petzle Ultralegere? Two of us are doing Denali's W Butt and have realized that we may want carry more than two pulleys (each!). A friend suggested that these almost-pulleys might be a good choice for the "C" half of a Z+C.

Any advice?

[Alpinfox]

I've tried to use those things before and I was not impressed. I pretty much agree 100% with this review I saw on the REI website:

 

Don't get this for an emergency pulley--won't function. You have to specifically use an oval biner (who carries those anymore?) and, more importantly, even when using an oval, the wheel is too narrow for it's diameter--meaning that the wheel capsizes (rope slips off the wheel) within 3ft of hauling and then gets pinched between wheel and biner spine. Pulley's are useful for emergency situations, but get a real (lightweight) pulley or get a DMM Revolver.

 

 

The Petzl Oscillante Pulley weighs 55g and costs $15. Works well, though it is still not a "prusik-minding" pulley. Not sure how you do your crevasse rescue, so maybe that isn't an issue.

 

I've been wanting to try one of those DMM revolvers, but never have. They make a locker version now, but its really expensive.

[korup]

They are less than worthless. They require not just any oval biner, but ones with wide gates and shallow curves, and even then they work like crap.

[Jens]

Like was said before, only some of the ovals fit the pulley.

[snoboy]

Look into the real pullies that Rock Exotica is making these days. Super small, light, and still full strength... beautiful pieces of jewellery almost.

 

This would be perfect...

[Le Piston]

I bought one of these several years ago to go with my locking oval biner thinking it was a great idea. It was a great idea, just didn't work well in real life. I'd rather not compromise function and safety for a few ounces saved on one of these pseudopulleys. I would suggest practicing your crevasse rescue technique and system before you need it in the mountains. You can't always count on other teams being there to help when you need them. Best of luck on McKinley!

[Maxtrax]

The ultralegre is a steaming pile in my opinion. The weight savings of an ultralegre + specific oval is negligible compared to the oscillante or SMC green crevasse rescue pulley + wiregate or superfly locker and the usability is severely decreased. I bought one for my first glacier trip and have ever since tried to give it away with almost every piece of climbing gear I've ever sold, to no avail.

Edited May 13, 2009 by Maxtrax

[pjc]

Alpinfox (and others), regarding the review you posted. I'm under the impression that for safe rope handling (i.e. handle high loads of a pulley system) the pulley diameter has to be a few times the rope diameter. The DMM Revolvers are just 10mm diam, so that'd stress the rope quite a bit. Thoughts?

[Alpinfox]

Alpinfox (and others), regarding the review you posted. I'm under the impression that for safe rope handling (i.e. handle high loads of a pulley system) the pulley diameter has to be a few times the rope diameter. The DMM Revolvers are just 10mm diam, so that'd stress the rope quite a bit. Thoughts?

 

In the case of a crevasse rescue scenario, I don't think the pulleys should be seeing very high forces. Maybe 2kN max?

 

There are folks on here who know the physics of these systems much better than I, so maybe they will chime in.

 

However, ropes get bent over single biners (small diameter) in much higher force situations (lead falls) without catastrophic consequences, so my gut inclination is the revolver isn't unusually "high stress".

[G-spotter]

In over 20 years of climbing I have never actually had to use a pulley on a glacier, so I carry two of these on two old ovals that they work on; seems like a reasonable tradeoff between not working if needed and not using so not needed.

[mattp]

In over 20 years of climbing I have never actually had to use a pulley on a glacier, so I carry two of these on two old ovals that they work on; seems like a reasonable tradeoff between not working if needed and not using so not needed.

Agreed. I have never fallen into a crevasse. However, I think you and I have done most of our climbing in BC and Washington, no? I think climbers in such places as New Zealand and Alaska fall into crevasses more often.

[rocky_joe]

The ultralegere seems like a waste of money. I have a fixe, but no need to carry all that for such an expedition...I'd be inclined to take a few BD ovals. They do quite well, esp if you're on a super thin 8mm glacier line. Haven't used the DMM revolvers, they may also be useful.

[denningsrogue]

Take a look at the SMC CR pulley. Hard to improve on from my perspective.

[G-spotter]

In over 20 years of climbing I have never actually had to use a pulley on a glacier, so I carry two of these on two old ovals that they work on; seems like a reasonable tradeoff between not working if needed and not using so not needed.

Agreed. I have never fallen into a crevasse. However, I think you and I have done most of our climbing in BC and Washington, no? I think climbers in such places as New Zealand and Alaska fall into crevasses more often.

 

From the perspective of BC, Washington doesn't even have glaciers Matt.

[snoboy]

Alpinfox (and others), regarding the review you posted. I'm under the impression that for safe rope handling (i.e. handle high loads of a pulley system) the pulley diameter has to be a few times the rope diameter. The DMM Revolvers are just 10mm diam, so that'd stress the rope quite a bit. Thoughts?

 

Yup, a few...

 

If your Pulley Tread Diameter (PTD - actual surface rope runs on) is close to 4x the rope diameter, then you will preserve about 90% of the strength of the rope. Don't forget most people are using 7-9mm ropes for glacier travel.

 

As PTD -> 0 you will obviously lose more strength.

 

You lose about 1/3 of the strength of the rope by tying a knot in it; so unless you have some fancy pants way of connecting the rope (sewn terminations for example) then there isn't much need for preserving 90% of the rope strength.

 

Unfortunatly I don't have the numbers for where the PTD:Rope Dia ratio is close to the knotted strength loss. It's something I have been thinking about lately as I am purchasing some new gear for our Rope Rescue team and want to keep weight down.

 

Let's make some assumptions now:

-We will not screw up, ie good solid rigging

-1 person load about 100kg

-On earth 100kg makes about a 1kN force.

 

Force in = Force out. The load is only 1kN. a 10:1 safety Factor (standard for most mtn rescue groups) means we now only need to look at keeping strength above 10kN... not too hard. Even that is a pretty conservative number, since we shouldn't be able to subject our system to shock loading - remember, 'good solid rigging.'

 

We will have to add a little extra force to overcome friction in the system, but the better the pulleys we use, the less of that will happen.

 

On a different track:

 

82g - Rock Exotica Mini Machined pulley

23g - Camp nano wire - can use something light here, no?

----

105g

 

12g - Petzl Ultralitepulley

80g - Petzl OK oval - reccomended for above

----

92g

 

Difference? 13g... and the Rock Exotica pulley is a prusik minder... which will make your ratchet operate more smoothly.

[Alpinfox]

For 165g, you can get a Petzl Mini Traxion which makes crevasse rescue and other light hauling systems a breeze.

[mkporwit]

The SMC CR pulley is also a PMP, is rated to 24KN so it preserves your 10:1 SF, and weighs in at only 64g... so with the nano it comes out just a hair lighter than the Petzl combo.

[snoboy]

Yes, but it's ^^^ efficiency will suck compared to a real pulley with bearings. Cost wise it's good for sure.

 

 

For 165g, you can get a Petzl Mini Traxion

 

Don't forget to add the weight of an appropriate biner to that.

 

 

I guess ultimately it comes down to each person's priorities of quality, strength, cost, weight, etc...

[passward]

Thanks all. Definitely ruling out the Petzl Ultralegeres.

I'm looking, right now, at pile of Denali gear thats bigger than my couch. For my knees sake, I gotta draw the line somewhere. Think I'll just do the C half of the Z+C setup running thru biners.

Seems the bigger issue for a 2-man team is actually getting an anchor set up in the first place so the rescuer can get to work.

[snoboy]

Whatever you end up taking, read the other discussion in the Newbies forum from a month or so ago about where to put biners vs. pulleys.

 

Short version: Put your most effecient pullies closest to the hauling team, put your biners closer to the load.

[mattp]

I think that if you go out and practice you will likely conclude that establishing the anchor is actually the easy part. With a two man team, a crevasse extraction is generally pretty hard - unless the guy down in the hole can climb out.

[korup]

You might want to consider: using 'biners instead of pulleys is going to make a tricky situation essentially impossible.

[passward]

snoboy - Wish I would have just taken your word for it: pullies close to the hauler(s); biners close to the "victim." The Newbie thread you referenced gave me a migraine. But I was finally satisfied when I followed the link you posted that showed "delrio's" graphic and calculations. Good stuff, thanks.