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Cams as Multidirectional


Original Post
Marco Velo · · Unknown Hometown · Joined Feb 2017 · Points: 0

Okay, so here's a question:

I've read in several places reference to cams as multidirectional in connection with the advice that in certain situations a multidirectional piece is highly desirable (as Jesus piece, e.g. or before traverse section). I believe I understand what "multidirectional" means: capable of withstanding a force in multiple directions. I also believe I understand why it would be desirable  in  cases such as these to have a multidirectional piece (because forces might pull in any of a number of potential directions and the piece must withstand these if it is to serve its purpose.) Please correct/qualify any of that if necessary.

 But here's my question: what, exactly, makes a cam particularly multidirectional? Is it because it rotates within its placement? (That doesn't seem "secure" as, say, Chauvin/Coppolillo use the term). Or simply because the stem is flexible? (That would seem to also apply to a big nut or hex on a wire?). Other reasons? Or is the multidirectional nature of cams exaggerated?

Thanks,

-marco

nathanael · · Riverside, CA · Joined May 2011 · Points: 348

It's the hope that a cam in a smooth parallel side crack will rotate within its placement. It's not a guarantee, and if the crack isn't smooth or parallel it's less likely to work as hoped.

Jordan Palamos · · Eugene, OR · Joined Jun 2015 · Points: 15
nathanael wrote:

It's the hope that a cam in a smooth parallel side crack will rotate within its placement. It's not a guarantee, and if the crack isn't smooth or parallel it's less likely to work as hoped.

Also, a TCU may rotate better in this situation compared to a unit with 4 lobes.

Scott and Sara · · Unknown Hometown · Joined May 2017 · Points: 0
Marco Velo wrote:

Okay, so here's a question

 But here's my question: what, exactly, makes a cam particularly multidirectional? Is it because it rotates within its placement? (That doesn't seem "secure" as, say, Chauvin/Coppolillo use the term). Or simply because the stem is flexible? (That would seem to also apply to a big nut or hex on a wire?). Other reasons? Or is the multidirectional nature of cams exaggerated?

Thanks,

-marco

Cams are multidirectional in ways that nuts/hexes are not because - given the right circumstances - they can rotate within the crack and resist an outward pull from multiple directions while still holding.  That said, if the crack is not parallel they can walk as they rotate, and can potentially become undercammed, which can be bad.

Marco Velo · · Unknown Hometown · Joined Feb 2017 · Points: 0

Gotcha. Small space between hoping for "rotation" and placing to avoid "walking," no? 

Derek DeBruin · · Unknown Hometown · Joined Jul 2010 · Points: 585
Marco Velo wrote:

Gotcha. Small space between hoping for "rotation" and placing to avoid "walking," no? 

Indeed. But you can test for anticipated upward pull by simply pulling on the cam in that direction and noting the effect on the placement.

B Owens · · Unknown Hometown · Joined Sep 2011 · Points: 60

In some placements, the only possible consequence of a cam walking is that the cam gets stuck, but does not become undercammed.  This kind of walking is bad/annoying in that you may lose a piece, but not bad in that the piece no longer protects you.  

In other placements, one possible consequence of a cam walking is that the cam tips out or disengages entirely, and is no longer protecting you.  This kind of walking is much worse.  

Why do we not have a word to describe this?

Matt Westlake · · Durham, NC · Joined Jul 2009 · Points: 588

"Why do we not have a word to describe this?"

Looks down: "Shiiiit..."

Sebastian Reichelt · · Unknown Hometown · Joined Oct 2017 · Points: 0

Cams may not always hold in every possible direction, but just compare that to the number of multi-directional nut placements you have ever found. (Well, yes, you can place two nuts in opposition ...)

wivanoff · · Northeast, USA · Joined Mar 2012 · Points: 472

Also, a cam placed in a horizontal crack (I'm looking at you, Gunks) can resist an upward and downward force without rotating.

Ted Pinson · · Chicago, IL · Joined Jul 2014 · Points: 190

Yeah, I agree that the degree of multidirectionality of cams is often overstated.  As others said, they’re multidirectional...to a point.  Not anywhere near as much as a bolt or tree, but significantly more than most nut placements.  Cams can walk out but they don’t tend to, and this is much less likely than a nut lifting out if it’s the first piece.  The point is to avoid zippering and to resist an upward pull, which even good nut placements don’t tend to do unless placed in opposition.

rgold · · Poughkeepsie, NY · Joined Feb 2008 · Points: 525

Nuts are multidirectional in horizontal cracks too...

There seems to me to be a certain amount of wishful thinking in the multidirectional cam claims.  Once the cam moves, a lot can happen, and uncertainty is the only sure rule.  Of particular concern is if the cam is supposed to function as ordinary pro as well, and the next piece after the cam fails.  In this case, the cam is rotated up and then down under heavy jerks.  It is pretty hard to be sanguine about the reliability of such a placement under those conditions.

I prefer to think in other terms, the first one being whether the situation calls for a multidirectional piece.  Not every situation does, and some potential problems can be eliminated by getting the belayer up against the cliff face rather than several feet (or more!) away from the foot of the pitch.

If in my wisdom (or lack of it), I conclude a multidirectional piece is needed, and a horizontal placement isn't available,  then if at all possible I'm gonna rig something that is actually held down by something else.  If I can't find a way to make that happen, (no feature below for the upward directional holding piece) then and only then do I embrace the idea that a cam has a better chance of staying put than a nut under lifting loads, realizing fully the uncertainty involved in such an assumption.

Given that uncertainty, it makes sense to continue thinking about getting something multidirectional in higher.  Focusing on the first piece could make one insensitive to perfectly good solutions a little higher up.

First piece multidirectionality can be an issue in horizontal cracks too.  If the leader traverses horizontally form the belay and places gear in a horizontal crack, the possible sideways loading of a fall could rotate the gear out.  I think this problems is more critical with cams than with nuts, and I've had the somewhat scary experience of catching a leader fall in such a situation during which two of the four cams rotated out of the placement.  A nut is likely to be a better choice if there is a constriction for it.  If the crack is deep enough, the cam should be placed at an angle (not perpendicular to the cliff face) so that it is aligned with the anticipated resultant force.  And if the crack is too shallow for that, then a pair of opposed pieces is probably the way to go.

David Kerkeslager · · New Paltz, NY · Joined Jan 2017 · Points: 55
rgold wrote:

I prefer to think in other terms, the first one being whether the situation calls for a multidirectional piece.  Not every situation does, and some potential problems can be eliminated by getting the belayer up against the cliff face rather than several feet (or more!) away from the foot of the pitch.

This.

A reliable way to get someone to spray at you is to climb Horseman in the Gunks. The first placement is a nut about 3 meters off the ground. It's a good nut placement and if the belayer is up against the wall it will totally catch a fall. You get a cam placement about a 1.5 meters later from a very comfortable stance, so after that the belayer can move back from the cliff if they want.

But inevitably if you place that nut, someone comes over and warns you against the horrible dangers of not placing a multidirectional piece as your first piece, oblivious to the complete lack of a multidirectional placement at that point. Often they'll try demonstrate by yanking the rope after your climber has the cam in: which totally pulls the nut out because if you extended the nut, it's low enough that you'd deck.

The most ridiculous thing about this is if you just climb 4.5 meters and place the cam first, nobody will give you any trouble.

Dan Africk · · Brooklyn, New York · Joined May 2014 · Points: 285

As usual, rgold nailed it. The best protection against upward pull is a horizontal placement, and I think nuts or tricams are often more reliable, and certainly walk less, than cams in that situation.

Cams are not inherently multi-directional, and other pro is not inherently non multi-directional. For vertical cracks, cams will have a better chance of holding against upward pull than typical nut placements. Tricams are also better than nuts in this situation, especially with a deep, tight placement, but probably not as good as cams.

Russ Keane · · Unknown Hometown · Joined Feb 2013 · Points: 150

To me, it's that flexible stem, along with the four-lobe design, that makes it solid within a range.

Guideline #1: Don't be a jerk.

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