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Cam Angles In Small Cams

Original Post
Joel M · · Denver, CO · Joined Apr 2019 · Points: 5

I am aware that cam angles have been discussed ad nauseum on here, however some questions never seem to quite get answered. One thing I’m curious about is cam angles in smaller cams (.4>). With Wild Country’s upcoming Zero toting a cam angle of 17.6 degrees, it begs the question of what the ideal angle truly is. The primary gear manufacturers even seem to lack a consensus. Is Wild Country sacrificing real-world holding power with this cam angle increase, or does the theoretical holding power lost here simply not matter enough to affect the cam’s ability to hold in an actual fall? Of course the forces at play in any given climbing fall are both unique and complex, but the question is are there any falling scenarios in which a cam with a 13.5 degree cam angle would consistently hold where the same cam (i.e. all other factors held constant) with a 17.5 degree cam angle would not?

E Mann · · front range CO · Joined Aug 2017 · Points: 11

black totems

patto · · Unknown Hometown · Joined Jul 2012 · Points: 25
Joel May wrote: but the question is are there any falling scenarios in which a cam with a 13.5 degree cam angle would consistently hold where the same cam (i.e. all other factors held constant) with a 17.5 degree cam angle would not?

Yes plenty.  Any crack slick crack with low friction.  How slick and how, low a friction.  Well that is the questions.  I'm not sure I'd just 17.5degrees on slick fine grained rock.

I wouldn't be comfortable with a 17.5degree angle on the rock I climb.  I much prefer metolisus for my smallest cams as they have 13.25 and grip like hell in smoot parellel cracks.  Oh year black totems, but they are at the upper end of 'micro' cams in my book.   #0 and #00 metolius are my go to small cams.  It's all trade offs and 17.5degrees is trading off grip strength in parrallel cracks for bigger range.

(Totems get around some of this tradeoff with their unique and patenteded design.  Hence despite having a cam angle of around 20degrees, the effective angle is around 13 degrees.)
Joel M · · Denver, CO · Joined Apr 2019 · Points: 5

Patto, that attitude does seem to be a commonly held one, but I’m curious if you have any non-anecdotal evidence to back your view? Personally I generally would prefer a lower angle cam, especially on something like sandstone, so I don’t think that you’re wrong, I just am curious if there is some hard evidence that justifies your view. 

dindolino32 · · Unknown Hometown · Joined Feb 2009 · Points: 25

I second the black totems, support innovation, not alteration.

Joel M · · Denver, CO · Joined Apr 2019 · Points: 5

Haha, yes, black totems are the best small cam. However, until totem makes a smaller cam, or if a black or blue totem does not provide an adequate placement in a certain crack, we are left to choose between others for certain placements.

Cam Hook · · Portland · Joined May 2015 · Points: 95
dindolino32 wrote: I second the black totems, support innovation, not alteration.

Black totems are awesome but they aren’t micro cams. 

John Butler · · Unknown Hometown · Joined Apr 2016 · Points: 5

Black Totem vs. green DMM on left and red BD on right...

Taylor Krosbakken · · Duluth, MN · Joined Nov 2008 · Points: 673

^wrong totem. That's a totem "basic" or rather an alien in your case.

Most people are talking about this guy:

csproul · · Davis, CA · Joined Dec 2009 · Points: 330

That’s a totem basic...not THE black Totem

Eric and Lucie · · Boulder, CO · Joined Oct 2004 · Points: 140

There's no such thing as an "optimal" cam angle.  It is a compromise between holding (lower angle better) and range (larger angle better).  You want to be very careful with high camming angle in smooth rock.  My favorite small cams are the Totem Basics (unfortunately not currently made) but I have personally pulled one out of a slick sandstone crack (Eldo) simply by testing it by hand...

MorganH · · Unknown Hometown · Joined Sep 2010 · Points: 185

I want a cam that actually fits in the crack. At some point, with tiny cams, they have such a small range that they're barely ever actually usable if they don't have a slightly larger cam angle. I'd sacrifice a bit of holding power for usable range. 

Ted Pinson · · Chicago, IL · Joined Jul 2014 · Points: 217

Out of curiosity, where do C3s and X4s fall into this?  My sense from using them is that X4s have a wider angle, as they seem to have a lot more range for a given size...does this mean a well placed C3 will hold better, however?  I mostly climb in slick rock and tend to reach for the C3s first for the narrower head, but I’m curious if this should be a factor as well, given the narrower margins of error in that range...

Franck Vee · · Unknown Hometown · Joined Apr 2017 · Points: 91

Well, as far a I am concerned, 0.4 is perhaps a bit big for a distinction. For me, there's mostly smaller than 0.3 (which is the black totem size roughly), and black totem & bigger.

And for my part, the dodgy thing about placing those smaller guys is that, well, it's hard to place them well. There's such a narrow absolute range in which they're usable, from overcamed to undercamed. If I'm placing a 0.1 (red X4) or a Metolius #00, I tend to be more concerned about it being really well placed than about its holding power. I know its holding power isn't great. I typically don't plan on taking huge whipper on it (or if that's planned, well, I know I'm risking a piece popping out with whatever that entails in the context...). If the crack a big deep at all, or the placement ackwared, gets hard pretty quickly to inspect properly.

I would take the trade-off of slightly more leeway to place the cam well but smaller holding power. Anyhow given its propably standing on tinny bits of rocks, those bits of rock may well be what ultimately gives up...

kevin neville · · Oconomowoc WI · Joined Jun 2013 · Points: 15

The black Totem approximately corresponds to the 0.2 X4.

The "holding power" of a small camming angle means greater forces within the cam (transmitted through the lobes to the axle) and also against the rock. For small cams that concentrate that force into a small area, and sometimes fail by deforming the materials or fracturing the rock, there is at least a theoretical argument for a larger camming angle, separate from the range advantage. The ideal angle would depend on the rock properties: slick but solid favoring a smaller angle, rough but potentially breakable favoring larger.

patto · · Unknown Hometown · Joined Jul 2012 · Points: 25
Joel M wrote: Patto, that attitude does seem to be a commonly held one, but I’m curious if you have any non-anecdotal evidence to back your view? Personally I generally would prefer a lower angle cam, especially on something like sandstone, so I don’t think that you’re wrong, I just am curious if there is some hard evidence that justifies your view. 

Um yeah.  Physics, mathematics, et... You know the pricinciples that your rely upon for the design, manufacture and construction in most of the modern world.


As an engineer I don't usually have the luxury of testing something before it performs life critical task.
Joel M · · Denver, CO · Joined Apr 2019 · Points: 5
patto wrote:

Um yeah.  Physics, mathematics, et... You know the pricinciples that your rely upon for the design, manufacture and construction in most of the modern world.


As an engineer I don't usually have the luxury of testing something before it performs life critical task.

Yes, physics tells us that the lower the cam angle, the greater the holding power and vice versa. However, this principle alone is not sufficient to conclude that there are real-world placements in which a 17.5 degree cam angle would fail where a 13.5 degree cam angle would hold. This is because of the possibility that, although it exists, the disparity in holding power between these cam angles is not great enough to produce real-world differences.

Franck Vee · · Unknown Hometown · Joined Apr 2017 · Points: 91
Joel M wrote:

Yes, physics tells us that the lower the cam angle, the greater the holding power and vice versa. However, this principle alone is not sufficient to conclude that there are real-world placements in which a 17.5 degree cam angle would fail where a 13.5 degree cam angle would hold. This is because of the possibility that, although it exists, the disparity in holding power between these cam angles is not great enough to produce real-world differences.

Okay, let me get this straight.

You turn down an argument based on physics that because... what? No hard numbers calculation is provided? No real-world test data on scenario no one has ever conducted? And your justification for turning it down it....

.... a purely opinion-based guesstimation that the difference (although real, as you admit yourself) is not big enough to actually matter in practice?This seems convoluted to me. Are you seriously asking, or mostly looking for someone else to comfort your current point of view?

It also seems like a dangerous way to see things about climbing.

" Oh, sure, in theory a knot could roll, but there's so much friction in a knot, it'll never roll in a real-world use .... "
Former Climber · · PA · Joined Jun 2019 · Points: 2
Franck Vee wrote:

Okay, let me get this straight.

You turn down an argument based on physics that because... what? No hard numbers calculation is provided? No real-world test data on scenario no one has ever conducted? And your justification for turning it down it....

.... a purely opinion-based guesstimation that the difference (although real, as you admit yourself) is not big enough to actually matter in practice?This seems convoluted to me. Are you seriously asking, or mostly looking for someone else to comfort your current point of view?

It also seems like a dangerous way to see things about climbing.

" Oh, sure, in theory a knot could roll, but there's so much friction in a knot, it'll never roll in a real-world use .... "

Friction coefficients between aluminum and common rock types have been published, and the math is not hard.

Yet there’s a lot of arm waving about “lab vs real world” and hocus-pocus.

If WC says 17.whatever works, I believe them.  Because the math supports it.
Joel M · · Denver, CO · Joined Apr 2019 · Points: 5
Franck Vee wrote:

Okay, let me get this straight.

You turn down an argument based on physics that because... what? No hard numbers calculation is provided? No real-world test data on scenario no one has ever conducted? And your justification for turning it down it....

.... a purely opinion-based guesstimation that the difference (although real, as you admit yourself) is not big enough to actually matter in practice?This seems convoluted to me. Are you seriously asking, or mostly looking for someone else to comfort your current point of view?

It also seems like a dangerous way to see things about climbing.

" Oh, sure, in theory a knot could roll, but there's so much friction in a knot, it'll never roll in a real-world use .... "

Franck, I’m not claiming that Patto’s general argument is wrong, I am claiming that it has failed to provide evidence that there is a significant real-world difference between the cam angles discussed. So, you see, I am not rejecting the argument, I am pointing out that the primary principle it is assuming (i.e. small angle = more holding power) is not sufficient to justify the conclusion that a 17.5 degree cam angle will fail where a 13.5 degree cam angle will hold in any actual climbing scenario. Do you see the difference?


Yes, I believe that the principle stated above is real. That’s been made clear here. As has also been made clear above, I implement this principle into my gear choices. While I don’t have definitive evidence that a 13.5 degree cam angle will hold in some places that a 17.5 degree cam angle won’t, I certainly see it as a high possibility. This post was asking for evidence beyond the standard “lower angle = more holding power” principle. I hope that clears up my views and intentions for you. 
Former Climber · · PA · Joined Jun 2019 · Points: 2

From US Patent 20060231708A1, which was for adding high friction inserts to cam lobes:

I’d expect 6106 to be quite similar to 6061 in terms of friction with rock, so easy enough to calculate the maximum cam angle that would work for each rock type.
Guideline #1: Don't be a jerk.

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