Cam placements in outward-flaring cracks


Original Post
AaronJ · · Japan · Joined Dec 2013 · Points: 178

I am curious about the issue of the performance of regular cams when their lobes are unequally retracted, and the potential advantages of offset cams and Totem Cams in similar placements.

It seems to be "common knowledge" that regular camming devices like BD C4s should be deployed with all of their cams retracted equally, but I also recall reading recently in a thread on here that at least theoretically, all the lobes should be loaded equally regardless of their relative retraction. (The instructions for the C4 do not seem to have any warning against uneven lobe retraction, unless I'm missing something) I have personally not noticed a difference in performance when weighting and bounce-testing unevenly deployed cams, but my experience in that area is relatively limited. If this is the case, then is the issue one of unexpected movement of the unit in the event of loading? Or is the whole thing a non-issue? I guess the TL;DR question for this paragraph is: Why have I always been told not to place cams with the lobes unevenly retracted?

If there is no significant difference in performance between a cam placed with all four lobes retracted evenly and one with two lobes (let's say the outer two) retracted less than the other two, then what is the advantage of offset/hybrid cams? Do they cover ranges where the uneven placement of a regular cam would result in the two less-retracted lobes being fully open? I have never used offset cams so I am not at all familiar with their use outside of what I have read.

Finally, are Totem Cams really superior to regular cams in outward-flaring placements? If there is nothing wrong with a slightly offset C4 placement, then I'm not sure what it would mean for a different cam in the same placement to be "superior." I think I understand the other advantages of Totems (spring tension, downward flares, etc.), and that their unique stem design allows for two-lobe placements, but does it really grant a significant advantage in placements where all four lobes are touching rock? The way their stems engage the lobes individually would seem to have some positive effect, but if the lobes of single-stem cams all engage the rock with the same amount of force regardless of their relative retraction, what does the Totem Cam improve on in this particular area?

Kevin Mokracek · · Burbank · Joined Apr 2012 · Points: 200

Do you even off set bro?

Muscrat · · Unknown Hometown · Joined Oct 2011 · Points: 3,610
AaronJ wrote: Why have I always been told not to place cams with the lobes unevenly retracted?
What i want to know, is "WHO TOLD YOU THAT"?
As an extension to this hypothesis, cams only work in parallel sided cracks.
REALLY?
eli poss · · Durango, Co · Joined May 2014 · Points: 456
AaronJ wrote: If this is the case, then is the issue one of unexpected movement of the unit in the event of loading?
Yes. What makes totems better in these placement is the narrow head width. With a totem, you might have 3 or 4 lobes with good retraction compared to 2 a different cam. Obviously offsets will be even better as they have lobes that are actually bigger, but for gentle flares totems are usually good enough.
Kevin Mokracek · · Burbank · Joined Apr 2012 · Points: 200
eli poss wrote: Obviously offsets will be even better as they have lobes that are actually bigger, but for gentle flares totems are usually good enough.
I don't have any numbers to back this up but all things being equal I always place a Totem before I reach for a MC off set or any other type off set. It's been my experience that Totems hold better in 9 out of 10 flared placements and inspire way more confidence than regular off sets.
AaronJ · · Japan · Joined Dec 2013 · Points: 178
Muscrat wrote: What i want to know, is "WHO TOLD YOU THAT"? As an extension to this hypothesis, cams only work in parallel sided cracks. REALLY?
Luebben, Rock Climbing Anchors:
"When setting cams, seek a uniformly parallel spot in the crack where the crack walls are parallel-sided, not wavering, ridged, bumpy, tapering, or flared. You can set a camming unit in non-parallel spots, and often must, but the best, most predictable placements exist in a parallel area of the crack."

Metolius cam manual :
"Make sure that the all cam lobes are retracted evenly"

To be fair, at least in Luebben's case it seems to be a comparison between ideal and acceptable. Nevertheless, in general it seems to be a popular refrain. I read several comments in threads on MP this morning that made similar claims, which in part prompted my question.

eli poss wrote: What makes totems better in these placement is the narrow head width.
Aha. I hadn't considered the fact that the narrower head width means that the difference in retraction among the cam lobes would be less. Thank you for pointing that bit out.

Kevin Mokracek wrote: Do you even off set bro?
I wish. Might do better with the ladies if I did.
patto · · Unknown Hometown · Joined Jul 2012 · Points: 25

There seems to be confusion between cracks that are flared in the direction of the pull and cracks which are flared perpendicular to the direction of the pull.

-The latter results in uneven lobe expansion which in of itself isn't a big issue as long as all other cam needs are met. Aka good contact, not tipped out, etc..

-The former if it is an opening flare can result in a cam popping out or breaking due to increased effective camming angle. Totems and cams with larger camming angles perform better in such flares.

AaronJ · · Japan · Joined Dec 2013 · Points: 178

Patto, thank you for clarifying the difference there. There may indeed be confusion on the part of some who have praised the performance of Totem Cams in flaring cracks. Their strength in cracks that flare parallel to the direction of pull (downward-flaring) is well documented. In this case, I am asking in particular about cracks that flare perpendicular to the direction of pull (outward-flaring). eli poss has already pointed out one advantage (narrow head width) they have in this regard.

patto · · Unknown Hometown · Joined Jul 2012 · Points: 25

Yes. I think Totems get excessive undue credit for performance in outward flaring cracks. Event the new Yosemite guide book raves about them for such placements. Their narrow head, helps but other cams have narrow heads too.

It doesn't help that pin scars often flare in both directions so it confuses the issue.

Totems are great cams but for a simple outward flaring crack most cams can cover it unless the flare is very large. In which case, offset cams...

Brian L. · · Unknown Hometown · Joined Feb 2016 · Points: 90

As other's have said, there's a difference between "ideal" and acceptable. You'll almost never have a perfect 100% evenly contracted cam. But in general this is the best situation, and should be sought above less ideal placements.

A regular cam can be placed in a small angle flair and be fine. as long as it's not tipped out on one side, and/or severely over-cammed on the other, and it isn't in danger of walking out of the crack.

To the point of offset vs regular cam, it's when the crack is more severely flared, where you CAN'T get a good placement with a regular cam that these come into place.

AaronJ · · Japan · Joined Dec 2013 · Points: 178

Why is a perfect 100% evenly contracted cam the best situation?

Brian L. · · Unknown Hometown · Joined Feb 2016 · Points: 90
AaronJ wrote:Why is a perfect 100% evenly contracted cam the best situation?
In my mind, less risk of walking and opening up. Obviously this depends on the rock features around the placement too, though.
John Ryan · · Poncha Springs, CO · Joined Aug 2012 · Points: 165

I had always wondered if a regular cam in a flared crack would hold a lead fall. Last summer I was leading a hard for me trad line in 11 Mile. I had a bomber X4 placed and decided to place a 0.75 C4 six inches or so higher due to the impending crux. Two of the C4's lobes were engaged perfectly with the crack at about 50% retraction while the outer two lobes were barely retracted and barely engaged with the flaring crack. I fell off at the crux which ripped the flared placement right out. It was an obviously poor placement which I got to verify as such.

Kevin Mokracek · · Burbank · Joined Apr 2012 · Points: 200
John Ryan wrote:I had always wondered if a regular cam in a flared crack would hold a lead fall. Last summer I was leading a hard for me trad line in 11 Mile. I had a bomber X4 placed and decided to place a 0.75 C4 six inches or so higher due to the impending crux. Two of the C4's lobes were engaged perfectly with the crack at about 50% retraction while the outer two lobes were barely retracted and barely engaged with the flaring crack. I fell off at the crux which ripped the flared placement right out. It was an obviously poor placement which I got to verify as such.
This is a placement where Totems really shine IMO. A regular cams outer lobs and even an MC Off Sets outer lobes won't get much bite. A Totems lobes are evenly loaded or you can clip the inner lobes only and load those if the placement is really shallow.

I have been using MC off sets and Aliens for years and Totems for the past 4 years or more and I just don't see too many places where an MC or Alien off set works better than a regular Totem, pockets, outward flared, downward flaring, pin scars. Regular Totems shine in all those placements.
ViperScale · · Unknown Hometown · Joined Dec 2013 · Points: 235

I have had to aid up a flared crack with a cam that only had 2 lobes barely in contact. Probably don't want to take a big fall on something like that but it will still hold alot of weight.

This is just part of climbing trad every time you place a piece of gear you have to judge have good of a placement. You aren't always going to have a perfect placement but sometimes it is either place a few questionable pieces or run out 30ft you go with gear that may or may not hold.

Spencer Perry · · Unknown Hometown · Joined Mar 2016 · Points: 65
John Ryan wrote:I had always wondered if a regular cam in a flared crack would hold a lead fall. Last summer I was leading a hard for me trad line in 11 Mile. I had a bomber X4 placed and decided to place a 0.75 C4 six inches or so higher due to the impending crux. Two of the C4's lobes were engaged perfectly with the crack at about 50% retraction while the outer two lobes were barely retracted and barely engaged with the flaring crack. I fell off at the crux which ripped the flared placement right out. It was an obviously poor placement which I got to verify as such.
I took a similar fall on a .5 X4 placed in a granite pin scar. The lobes in the shallower top section of the crack rotated out of the crack completely, and the other two lobes held. It wasn't a super long fall, about 4 feet above the cam but I was still pretty psyched that it held.
Guideline #1: Don't be a jerk.

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