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timpanogos
Oct 1, 2002, 6:40 AM
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The following analysis proved interesting: Given the following rack:
Metolius TCU’s #0 thru #4
Wild Country Forged friends #2 - #4
If each cam were compressed to 66% - each cam is in the range of 80% (average) of the next size ups 66% value. Now add the following cams to this rack:
Wild Country Zeros # Z3 – Z6
Black Diamond # .75 – 3.5
CCH Alien #1
Each cam is now in the range of 90% (average) of the next size ups 66% value.
Next to analyze the doubling up capability of the mixed sets. I used the following four tests. They assume that a range of 50% – 90% is safe (John Long, Climbing Anchors), and 66% is optimal:
1. What compression % is needed to hit the 66% value of the next larger size?
a. 6 of 20 cams were in the 50% to 90% compression range.
2. What compression % is needed to hit the 66% value of the next smaller size?
a. 10 of 20 cams were in the 50% to 90% compression range.
3. What compression % is needed to hit the 50% value of the next larger size?
a. 1 of 20 cams were in the 50% to 90% compression range.
4. What compression % is needed to hit the 50% value of the next smaller size?
a. 18 of 20 cams were in the 49% to 90% compression range.
b. The 2 that missed were the #0 and #1 TCU – with sizes being so small at this end, the negative effect is minimal.
I was also able to come up with a color scheme, where you can get colored racking binners that are coded to body part sizes (finger tip, 1st knuckle, …) were 2 cams are assigned the same color (which at least one cams web matches). I was able to keep 15 of the 20 cams with the same color biner as it’s web – you could color tape the other 5 cams to complete the scheme.
Bottom line, this rack has a nice spread (10% difference from cam to cam, splitting the single vendors 20% steps in half) With a 90% cam doubling for any given size with the next lower sizes 50% compression size. The other 10% were the 2 smallest tcu’s that just missed the 90% - and the ranges are so small as to not really matter.
If anybody is interested I have an excel spread sheet that has all the min/max/range/66%/50% values as well as all the next and last compression percentages, web color and proposed sizing color. Pm with an email and I’ll be glad to send it to you.
[ This Message was edited by: timpanogos on 2002-09-30 23:41 ]
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winkwinklambonini
Oct 2, 2002, 12:20 AM
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Huh? How much time did you spend measuring all those cams? I did a similar thing with the space between the wall and the fridge, it has a nice flare from top to bottom. I just took each cam and found it's range in the crack by how far it goes up or down with an acceptable fit.
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camhead
Oct 2, 2002, 1:24 AM
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damn! interesting!
My scientific method for having an even spread of cams is a bit simpler. I just buy a lot. I'm pretty sure that I have all the widths covered... but occasionally I do get into that proverbial tight spot, where I don't have the right size.
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wlderdude
Oct 2, 2002, 2:10 AM
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That is really impressive.
The problem with trying for a "full set" is that thereare really only three sizes of pro.
1. Too big
2. Too small
3. Fits
The socet set mentality of a size to fit every crack is not a bad model by any means, it just looses relevancy unless you are setting up top rope anchors and only use a size at a time.
What I want to do is get a rack heavy in the hand to fist size cams so I can climb cracks that size. I don't have the stength to climb finger tip sized cracks, so I won't buy them until I am. This model works for crack climbing, which is when you really need cams anyways.
As for racking, I think it is a good idea to color code, but it too has short comings. I don't want to haul my entire rack up a climb if I have doubles of everything, but just take the pro I think I will use. So, I can take the ____ color cams off my rack and ditch the size ____ hexes. Still a good idea to color code, but not as nice as a color coded screwdivers.
I am impressed with the work you have done. You must be an engineer obsesed with numbers. (I am as guilty as anyone of that)
I would like to see you spread sheet.
One other resource is Rock and Ice's "Mother of All Cam Charts." It is not avalible online witht he article, so just go to your local library.
climbingmoab.com has a chart that is not as good, but works, too.
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jhwnewengland
Oct 2, 2002, 2:42 AM
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There are great cam charts at http://www.clydesoles.com/ too. Good work on that rack design though, I like it!
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timpanogos
Oct 2, 2002, 5:12 AM
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Wink, not much time, got min/max numbers off the web, entered a few formulas in the spreadsheet. In fact if someone wants to use different brand, all you would need to do is plug the min/max, add the brands name, number and web color - and it will figure all the rest.
Wlderdude, actually I did not think of it as the socket set idea, but then again, I guess I did - where I started was - I have a fingertip, first knuckle, 2nd knuckle etc. type of placement (actually main crack was, tight hand, loose hand, tight hand jam and I'm out of cams, but not out of crack/route).
First goal was to double up on these sizes. Second goal was to double up with something that could double up or down (since you half stepped the brands normal step). I had just heard (from this site) that it was always good to double up with a different brand so they were just a bit different - I wanted to see just how different, and the mix here did a wonderful 1/2 step complement - that mathematically worked out real sweet - we shall see what reality does.
Also, I suppose I have always carried way too much gear, but all those 3+ pitch onsite's that have brought so much excitement - at this point in my experience and level of climbing - I'll carry it. In my limited experience - with a 1 set cam rack, I've been in that -oh crap - the piece I really need is in the belay station below - so you max/min the placement for a mental on climb on.
As far as color needing a full rack, actually that's the point, finger tip is purple biner, no matter what/how many/or where racked.
P.S.
most of the climbs (5.6-8 range)I've done in BCC/LCC ate up small to medium sized nuts, TCU 0 - 4's, and smaller forged friends, with my 3.5 and 4 friends being the least used pieces. - but you are right, I would have been in trouble on main crack with out having more hand sized gear.
[ This Message was edited by: timpanogos on 2002-10-01 22:19 ]
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addiroids
Oct 2, 2002, 5:38 AM
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Not to sound like a dick, good work on all the smart guy stuff, but as a previous poster said, this is only necessary if need to cover an ever widening crack (got Zacher Cracker in your mind?).
Besides that, learn to place nuts and hexes. You will be much happier knowing you protected a whole pitch for $30 rather than $900.
TRADitionally yours,
Cali Dirtbag
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neph
Oct 2, 2002, 5:41 AM
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wow, that's pretty cool. not a bad idea..
I've got a cam chart thing that i've been working on. It's still a work in progress, but it has basic funtionality right now.
Check it out here: http://www.sage-tech.net/~harrisnw/newcams.html
-Nate
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timpanogos
Oct 2, 2002, 7:05 AM
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Cali,
Yea, I also followed many threads on this site with the Hex verses cam debates before I bought any gear. I tended to fall short of the old school ethics and went new school cams - I don't own any cow bells
As I mentioned, the climbs I've done do like medium sized nuts - I have two sets and always go for a nut placement first - but then I have been doing easy 5.6-7 stuff - as I (hopefully) improve - and get to those cruxie, pumpy placements, hey I have no pride, I'll slap a cam (I'm an old fat fart).
Also being an old fat fart, I have 3 teenagers who also love to go, but darn kids have no gear - 2 belay stations and lead eat it up in a hurry.
I'm confused though, on the flaring crack deal that you mention and this scheme only seeming valid for this- once again, my intention was to double up on cams, I had 12, adding 8 more gave a double up on the original 12's optimal/safe ranges. In all cases, a given body size has two cams that are gaurenteed to be in the safe range (50-90) and in most cases 3 (1/2 size up and 1/2 size down) where the 3rd is somewhat better than just marginal (40-90).
Example:
WC #2, BD #1 WC #2.5
BD#1 is full hand (on me) with cam at 52%
I come across a full hand placement, and drop it. Along comes another full hand, I grab my WC#2.5 it cams in on the exact same size as the BD#1 at 81% - now climbing on, I hit yet another full hand placement, not as optimal as the first two, but still safe, I grab my WC#2 it cams in on the exact same size as the 1st DB#1 at 45% - a little far open - but it's there.
Of course this is all theory,
What did I miss?
Chad
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jamison
Oct 2, 2002, 4:44 PM
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Holly over analysis Batman!!
I think I may have missed the point of this thread, but...
My position is this:
Black Diamond cams have the widest range of usable motion. They are by far the most expensive, but that is what happens when your the best.
A few points:
BD cams ALWAYS have two cams that fit the same crack. Typically three.
All of the other major brands typically have one or two that fit the same crack and rarely three.
DMM and HB cams bunch several of the cams together. Meaning that the minimum size of the cams varies by something approaching a tenth of an inch!! A tenth of an inch is hard to judge even when your not hanging by your fingernails. Black diamond has three cams that cover the range of 5 DMMs.
Based on my analyis of cams which was created using the manufacturer recommended ranges of motion... A full set of Rock Empire cams is cheap and covers a large range of cracks. Unfortunately there are several sizes where only one cam will do the job. supplement the set with maybe 6 black diamond cams (roughly every other size) and you can protect a lot of crack for about $800 with 14 cams.
And avoid the analysis-paralysis.
Jamison
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winkwinklambonini
Oct 2, 2002, 4:59 PM
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One set of BD's
One Set of Metolious
Less cams with greater versitility
or
More cams with less wieght
or
combo
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paulc
Oct 2, 2002, 5:19 PM
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While I agree that BD has greater range, I don't really agree with the dissing of other vendors cams. Why not.
Well with DMM for instance, I spend the same money, cover the same range and have more pieces. I like to place lots of gear so more pieces is better for me. That way when I get the the station at least I have a bunch of stuff left over to make an anchor.
Sure the cam I have might not be the exact right size, but if it is close then there is most likely a place that I can get it in within a couple of feet of crack.
Plus DMMs have the extendo slings which reduces my draw count and helps keep the rack weight down.
Really it comes down to personal preference. Arguing about ranges on cams is like arguing about the quality of the head on your beer vs mine. Its all good, but its the taste that counts.
Paul
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curt
Oct 2, 2002, 5:36 PM
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Wider range = less holding power. All other things being equal, it is important to note that any type of camming device that relies on a section of a logarithmic spiral for the cam shape (and all of these do) will trade off range for holding power.
This is also true for Tri-Cams and the original Abolokov (sp?) cams. So, range of fit may not be the only thing to consider when selecting these things.
Curt
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tradguy
Oct 2, 2002, 5:39 PM
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jamison,
Or instead of spending $560 for 9 BD camalots (#.2 to #3.5), you could buy 12 WC Tech Friends (#00 to #4) for $60 less to cover the same range and have 3 more pieces to place when you would have been otherwise out of gear if you'd had the camalots, and carrying the same amount of weight. Camalot range is way over-rated. 1 cam is good only once per pitch. If you've used it and don't have another, you're out of luck.
I'm a big fan of the Friends, especially since they added a #1.25 and a #1.75, because now they have 4 cams that will fit a 1" crack.
The only benefit of Camalots is they've been the most popular out west in the US, so alot of the beta you get is something rediculous like "bring an extra blue camalot". What the hell is that??
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transse
Oct 2, 2002, 5:50 PM
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Interesting, I have basically that exact rack and am very happy with it. I never really analyzed anything but I use what works. Nice....
Jake
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jamison
Oct 2, 2002, 5:58 PM
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Firstly, regarding dissing manufacturers. I don't think I dissed anyone. I just state the facts.
Fact:
DMM has 5 cams that range from .67 inches to 1.6 inches with the minimum sizes: .67 .75 .83 .91 and .98
BD has 3 cams that range from .61 inches to 1.58 inches with min. sizes: .61 .80 and .96
The point is simply. I would rather have three cams to fumble around with than five.
On to the quantity versus "quality"....
I agree to some extent. That is why 8 Rock Empire cams for less than $250 bucks makes good sense supplemented with some wide ranging Black Diamond cams.
Oh yeah, and the more range=less strength. I don't know for sure, but what I hear is that the the double axles of Black Diamonds is what takes care of this problem. By moving the pivot point further back, greater camming power is achieved when the cams are at their limits. Its all about the lever.
Also, I like all the cams. A case can surely be made for any particular brand...
I like the "U" shape of cams like metolius. I don't so much like the Black Diamond "T" frame. But that is me.
I think the main point is this... The beauty of a cam is that it is simple to use. Black diamond has made this even better with wide ranging cams (but their trying to bleed me dry at $100 a pop).
Jamison
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tradklime
Oct 2, 2002, 5:59 PM
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My 2 cents...
-Camalots are too heavy and bulky.
-Rigid friends have a rigid stem which complicates their placement in diagonal and horizontal placements. Also the stem can hinder their placment in the smaller sizes.
-Double stem cams won't flex in one direction, this can cause issues with placements receiving multi-directional forces, especially shallow placements
In my opinion, buy a full set (same brand) of light weight inexpensive single stem cams. These will cover most sizes you will need and are sized to cover a full range with overlap. Augment with aliens, simply the best overall.
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curt
Oct 2, 2002, 6:41 PM
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Jamison,
I did not mean to say that Camelots are bad, just to remind everyone of the inherent design trade-offs for these things. You do trade off usable range for holding power, though. The 2 axles of the Camelot versus the single axle of the other devices has nothing to do with it, as this does not affect the expansion rate of the cams as the device is loaded. This is a common misconception. In fact, if you were to "straighten out" the cams and envision them as stoppers, the point becomes more intuitive. A stopper with a narrower (less)taper will exert more outward force on the sides of a crack than a stopper with a larger taper. However, the stopper with the larger taper will have a larger range of placements. I hope this helps.
Curt
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timpanogos
Oct 2, 2002, 7:13 PM
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Tradklime,
"In my opinion, buy a full set (same brand) of light weight inexpensive single stem cams. These will cover most sizes you will need and are sized to cover a full range with overlap"
This was kind of the point of the thread - after I have bought my first cheap set, but now find I want to double up - what should I consider then.
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jamison
Oct 2, 2002, 7:49 PM
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Curt,
I'm not following. I understand the stopper thing. That makes sense and I agree. For a stopper. I don't understand how you relate it to a cam.
I think the double axle issue is critical. It changes everything and here is why:
Assuming a vertical parallel crack...
On a single axle cam(assuming 4 cams), the force exerted upward on the cam, in a balanced placement, is 1/4 the downward force of the fall(F). The moment(torque) created by the cam equals .25*F*x where x is the radius of the cam at the point of contact.
For a Camelot, the distance x is increased by the seperation of the two axles and therefore increases the moment. This moment is resisted by both the rock, and the camming unit itself. And they balance out, otherwise the unit would move.
So I can't figure why the resisting force would not be greater for a double axle unit.
Jamison
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jamison
Oct 2, 2002, 7:55 PM
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Tradguy,
Your arguement for WC friends makes sense. Unfortunately I don't know much about them.
Jamison
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drector
Oct 2, 2002, 8:19 PM
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The BD cams get their added range from the location of the cams. The camming angle is similar or exactly the same as most other manufacturers. There is no loss of strength because of the dual axles.
The dual shaft allows the cams to close further before the tips of the cams rotate to be on the other side of the device and hit the opposing rock. I believe this is where the extra range comes from.
Sicne the cam angle is the same for almost every cam on the market, the holding power, or friction of aluminum on rock, is the same.
Dave
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tradklime
Oct 2, 2002, 8:55 PM
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timpanogos- buy aliens!
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tradklime
Oct 2, 2002, 9:06 PM
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jamison- Personnaly I have yet to hear a good argument for forge friends. Lets compare them to Clog cams.
Cost- Look at Barrabes, you can get Clogs between 25 and 30 bucks, as I recall
Holding power- made by the same company (WC), same exact cam lobe design.
Quality- again made be the same company, probably in the same factory.
Now add the versatility of a flexible, thinner stem. Where is the argument for forged friends? Someone please?
[ This Message was edited by: tradklime on 2002-10-02 15:05 ]
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curt
Oct 2, 2002, 10:24 PM
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jamison,
If you see the stopper analogy, you should also understand the situation as applied to cams--since it is the same. The higher the expansion angle (greater range) the smaller the force is that is exerted outwards to the sides of the crack. Conversely, the smaller the expansion angle (smaller range) the larger the force is that is exerted outwards against the sides of the crack. Remember, I am not referring to STRENGTH of the device in question, only to its holding power in rock.
I have reprinted the following from an article by John Middendorf, called "The Mechanical Advantage." I hope he won't mind, since I am citing the reference.
"In 1973 Greg Lowe filed for a patent for a sprung loaded version of the Abalakov Cam, manufactured some workable single cam units, and equipped his brother Jeff, who rapidly scooped some of the finest long routes in Zion National Park, notorious for its hard-to-protect parallel-sided cracks. These early single cam units had an elongated 30 degree camming angle, which provided limited stability, and their use never became widespread. In 1977 Ray Jardine climbed the Phoenix, Yosemite's first 5.13, with a new secret weapon. With an engineer's understanding of the principles of force and friction, Ray designed a sprung loaded opposing multiple cam unit with a more stable 15 degree camming angle and an innovative triggering mechanism. He kept his "Friends" cloaked in secrecy before his patent in 1978, and Yosemite was rife with rumors of Jardine's devices allowing for effortless protection placement on hard free routes. Before the commercial availability of Friends, a lucky inner circle of wall rats were able to buy his initial limited production of the innovative tools in the Camp 4 parking lot, and subsequently saved vast amounts of energy expenditure on the taxing big walls."
The reason the early cams did not hold was that the expansion angle was too large.
Regards,
Curt
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