Forums: Climbing Information: Gear Heads:
Cam Revolution: Link? Super? or Max?
RSS FeedRSS Feeds for Gear Heads

Premier Sponsor:

 
First page Previous page 1 2 3 Next page Last page  View All


jhwnewengland


Jun 10, 2005, 6:28 PM
Post #26 of 55 (11289 views)
Shortcut

Registered: Jun 2, 2002
Posts: 470

No Subject [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (0 ratings)  
Can't Post

I vote Max. Got to play with a prototype way back in '03 and it looked great then. Actually, it almost took a fall, but the leader had placed a #2 Camalot just above it, which caught him instead.

The Super Cam, when fully retracted, still has a small cam lobe on the "stem side." The lobe that rotates all the way around to the other side is just the larger half of this lobe. Tough to explain, but rest assured Reno that it's not just the stem pressing against the crack--there's still camming action going on.


Partner j_ung


Jun 10, 2005, 6:30 PM
Post #27 of 55 (11289 views)
Shortcut

Registered: Nov 21, 2003
Posts: 18690

No Subject [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (0 ratings)  
Can't Post

In reply to:
When the super cam is 100% cammed, aren't both lobs on the same side?

No, but I understand why somebody might think so. It certainly looks that way at first glance. The smaller, inside cams' surfaces just involve more of the cam spiral than we're all used to. Take a look at the cam spiral (I think you probably already know this, but I'll post for others' benefits):

http://www.bigwalls.net/.../Camfigs/camfig1.gif

Now take a look at the SC's small lobes:

http://www.rockclimbing.com/...p.cgi?Detailed=54715

The outer edge of the Super Cam's little lobes trace a longer section of the spiral. So, while it looks like you've run out of cam when the lobes invert, you're really just using a spot that is much farther down in the spiral, like so:

http://www.rockclimbing.com/...p.cgi?Detailed=54716

Admittedly (and I think I mentioned this in the review) the lower you go in its range, the less the lobes will contract, due to the logarhythmic nature of the spiral.

Again, I haven't used the others, so don't take this to ba commentary on them in any way, but I really love using the Super Cam. It's width is it's biggest down side, IMO, and in parallel (or roughly uniform) cracks, even that is an asset.


renohandjams


Jun 10, 2005, 6:33 PM
Post #28 of 55 (11289 views)
Shortcut

Registered: May 24, 2005
Posts: 616

No Subject [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (0 ratings)  
Can't Post

Ok, I don't know why I thought that. I played with it at the OR show, and left thinking "I have to rely on the stem's friction when it's fully cammed? I don't like it."

Sorry for being mistaken. So the small cam continues to hold, then you are right it would work like any other cam, it would just have a larger range, right?

I'll have to try a set of supers on the rock. Thanks for all of your input and feedback.

It seems that people either favor the super or the max, no so much the link, but I'm still getting a set in a couple of weeks to see how they do.

------------------------------------------------
-Kenny
http://www.TradRack.com
Free Email accounts, yourname@TradRack.com, 100 available
Email ben@tradrack.com with the name you want.
Only 5 have been taken so far.


healyje


Jun 10, 2005, 6:54 PM
Post #29 of 55 (11289 views)
Shortcut

Registered: Aug 22, 2004
Posts: 4204

No Subject [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (0 ratings)  
Can't Post

In reply to:
I vote Max. Got to play with a prototype way back in '03 and it looked great then. Actually, it almost took a fall, but the leader had placed a #2 Camalot just above it, which caught him instead.

The Super Cam, when fully retracted, still has a small cam lobe on the "stem side." The lobe that rotates all the way around to the other side is just the larger half of this lobe. Tough to explain, but rest assured Reno that it's not just the stem pressing against the crack--there's still camming action going on.

I personally think voting will have to wait until folks can hold, and get out and climb on, all three side-by-side in order to make a reasonable comparison and vote with their dollars. Making pronouncements / judgments before that amounts to premature speculation.


omenbringer


Jun 10, 2005, 7:02 PM
Post #30 of 55 (11289 views)
Shortcut

Registered: Sep 19, 2003
Posts: 248

Cam Revolution: Link? Super? or Max? [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (0 ratings)  
Can't Post

Damn J_Ung beat me to it.....

As has been said by Healyje, the Supercam is not that much of a departure from the Original Friend design in as far as the way it works, it just uses more of the logarithmic spiral. The revolutionary thing with the Supercam is the trigger setup which allows the cam lobes to travel through.

The Max cam, from what I gathered from a post by Malcom Daly, doesn't seem to really be all that revolutionary either. Although it looks like a cam, Malcolm seemed to describe its movement as more akin to the tricams than a regular cam.
In reply to:
Gang,
Be very, very careful of using the cam angle as a major determining factor for chosing a cam brand. Just as important is the choice of material for the cam lobes and the tooth profile. What matters is how well the cam works and I think that just about everything availble now works pretty well. The oldest still available cam, the Lowe/CAMP Tricam has varying cam angles: they start at 13 degrees and proceed up to 17 degrees out at the tips of the cam. Damn things work pretty well, too.
In reply to:
Our cam angles vary slightly but are well within the ranges discussed above. Anything more than that gets into trade secrets
I guess my vote for most revolutionary would probably go to the Link cam largely due to its hinging.

Of course I am not special enough to have gotten to play with any yet, just my premature speculation (Healyje when I first read that I swear it said something else) from posts, articles, and interviews I've read.


billcoe_


Jun 10, 2005, 7:28 PM
Post #31 of 55 (11289 views)
Shortcut

Registered: Jun 30, 2002
Posts: 4694

the best new cams [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (0 ratings)  
Can't Post

Hello fellow gear freaks:


In reply to:

I personally think voting will have to wait until folks can hold, and get out and climb on, all three side-by-side in order to make a reasonable comparison and vote with their dollars. Making pronouncements / judgments before that amounts to premature speculation.

Total agreement JH.

Hey, tossing this out there to the hordes: was anybody out there stupid enough to sell all of their Camalots on e-bay thinking that any 1 of these new cams would outperform them and they could replace all of their cams before they went to Yosemite in May with a newer better model? The thinking being that when the new cams come out the old ones will sell for less.

I mean, the Trangos were supposed to be out in the stores last Feb. I thought I could head to head check the Supercam vs Max Cam vs Link Cam vs C4. But that didn't happen.

So how many of you people were stupid enough to sell their... - Huh? Just me? :oops: WTF?

Stop laughing out there.

So how did that Yosemite trip go off you are thinking? Hey, I still own my origonal friends. I got them all cleaned and lubed, then hung them up in the basement so any extra tri-flow lube could drip before they dried. Then I walked off and forgot them. DOHHH.
So: all I have to say is that it's nice to have friends that still own cams!

I have a small Trango on backorder as Metolius don't go that small (thinking that I can use doubles of that size should another cam be better anyway), and am starting to wonder if I shouldn't just buy the Metolius cams now, and evaluate the small Trangos vs the C4's when they finally get out. Metolius stuff is always rock solid.

Summers here, I want to go climb. Guess I just rely on my old friends till this sorts out.

Cheers:

Bill


trenchdigger


Jun 10, 2005, 7:42 PM
Post #32 of 55 (11289 views)
Shortcut

Registered: Mar 9, 2003
Posts: 1447

Re: Cam Revolution: Link? Super? or Max? [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (0 ratings)  
Can't Post

In reply to:
In reply to:
I would be more worried about the supercam aligning.

Does anyone know when the super cam release date is? Is it out?

Can't wait to set the link cam in two weeks just to see how it really is.

When I was playing with the super cam at the OR show I thought it was a terrible design having both lobs go on one side. How is that supposed to hold me in a fall, two lobes on one side and useless stem on the other side of the crack. It seems like one side of the crack would have plenty of contact and the other side would have practically none (Tri cams?). Comments on this? I think the design is revolutionary, but I feel the most uncomfortable with this new radical design on the super cam (until I actually place it), even more uncomfortable than the link cam.

--------------------------------------------------------------------
-Kenny

As for the Super Cam design - it couldn't be more traditional or closer to the original Jardine Friend design - not in appearance, but rather in how it works: two sets of opposing cams producing a consistent camming angle to the rock - 13.5 degrees in this case exactly like the Power Cam. Appearances aside, the Super Cam works exactly like a Power Cam or an original Jardine Friend.

I'm not so sure about this.

If the stem is not centered between the lobe contact points, the force in the direction of the stem cannot be equal at each contact point. It must be larger on the side with the smaller lobes. It looks like this is exacerbated even more when the lobes are fully retracted, which also happens to be when the lobe radius (and therefore contact surface) is the smallest.

Still strong enough? Probably, but it definitely performs differently than a standard symmetric lobed cam.

~Adam~


kaylinr


Jun 10, 2005, 8:59 PM
Post #33 of 55 (11289 views)
Shortcut

Registered: Mar 13, 2004
Posts: 119

Re: Cam Revolution: Link? Super? or Max? [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (0 ratings)  
Can't Post

In reply to:


I'm not so sure about this.

If the stem is not centered between the lobe contact points, the force in the direction of the stem cannot be equal at each contact point. It must be larger on the side with the smaller lobes. It looks like this is exacerbated even more when the lobes are fully retracted, which also happens to be when the lobe radius (and therefore contact surface) is the smallest.

Still strong enough? Probably, but it definitely performs differently than a standard symmetric lobed cam.

~Adam~


I don't see how one set of lobes could exert more (or less) force than the other due to the offset stem. Whatever force one set of lobes exerts must be equal and opposite to the force the other set of lobes exerts. Right? :?: :?:


theman


Jun 10, 2005, 9:04 PM
Post #34 of 55 (11289 views)
Shortcut

Registered: Jun 4, 2005
Posts: 70

Re: Cam Revolution: Link? Super? or Max? [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (0 ratings)  
Can't Post

the trango cam when fully retracted looks like it would bottom out in a shallow crack because of that thing that sticks out the top?


trenchdigger


Jun 10, 2005, 9:31 PM
Post #35 of 55 (11289 views)
Shortcut

Registered: Mar 9, 2003
Posts: 1447

Re: Cam Revolution: Link? Super? or Max? [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (0 ratings)  
Can't Post

In reply to:
In reply to:


I'm not so sure about this.

If the stem is not centered between the lobe contact points, the force in the direction of the stem cannot be equal at each contact point. It must be larger on the side with the smaller lobes. It looks like this is exacerbated even more when the lobes are fully retracted, which also happens to be when the lobe radius (and therefore contact surface) is the smallest.

Still strong enough? Probably, but it definitely performs differently than a standard symmetric lobed cam.

~Adam~


I don't see how one set of lobes could exert more (or less) force than the other due to the offset stem. Whatever force one set of lobes exerts must be equal and opposite to the force the other set of lobes exerts. Right? :?: :?:
We're talking about two different forces here.

Assuming a static situation, the net force and moment in the system must be zero.

Now let's set up our coordinate system. Assume the X-axis is the axle of the cam. Assume the Y-axis is the stem of the cam.

For the net force in the X direction to be zero, you're right, both lobes must exert the same outward force.

For the net force in the Y direction to be zero, the situation is a bit different. In one direction, you have pull on the stem, and in the other direction, you have friction forces on each of the lobes pulling in the opposite direction.

Because of the nature of the asymmetric lobes, the stem will always be nearer to one side of the crack than the other. How "centered" it is depends on how retracted the lobes are. In every case, though, the smaller lobe will be forced to bear more of the load on the cam.

Take for example a placement in a 3" wide crack. Let's assume the stem is offset 1" from one wall (therefore 2" from the other wall) of the crack. Now let's pull down on the stem with 9 lb of force (in the Y direction). The force of friction (Y direction) against the larger lobe will be 3lbf and the force against the smaller lobe 6lbf.

A standard power cam in that same situation will distribute the load evenly and result in 4.5lbf exerted in the Y direction on each side of the crack.

Keep in mind that because of our constant camming angle, the outward (X direction) force for each of these situations is the same.

From this simplistic calculation, it seems that super cams would be far less suitable for flaring placements than a standard power cam with the same camming angle. I also fear that the uneven force distribution might lead to more rock failure due to shear under the smaller cam lobe despite Metolius' attempt to negate this by increasing the width of the cam lobe to distribute this force over more rock.

I don't mean to suggest that these cams are useless. There's no such thing as a free lunch here. But I think it's important to note that some compromises have been made to gain some featural benefits.

~Adam~


murf


Jun 10, 2005, 10:24 PM
Post #36 of 55 (11289 views)
Shortcut

Registered: Mar 15, 2002
Posts: 1150

Re: the best new cams [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (0 ratings)  
Can't Post

.... maybe you can just get a large range in virtually a unchanged cam, the C4.

No, you don't have to "relearn" how to place it. You don't have to "get used" to virtual axles. Ya don't have to worry about the "steel inner lobes".

Nope, you pretty much use it just like before except it weighs less...

Huh - that was easy.


trenchdigger


Jun 10, 2005, 10:39 PM
Post #37 of 55 (11289 views)
Shortcut

Registered: Mar 9, 2003
Posts: 1447

Re: the best new cams [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (0 ratings)  
Can't Post

In reply to:
.... maybe you can just get a large range in virtually a unchanged cam, the C4.

No, you don't have to "relearn" how to place it. You don't have to "get used" to virtual axles. Ya don't have to worry about the "steel inner lobes".

Nope, you pretty much use it just like before except it weighs less...

Huh - that was easy.

Now for my opinion on these shenanegans...

I have a rack of C4s from .5 to 5 with doubles of .75 through 4. Need I say more? :wink:

The C4 design is robust, simple, solid, heavier than some, lighter than others, and hard to screw up placing them, even blindly. They definitely perform well in their intended purpose, and for that reason I chose them for my primary set of mid-range cams. Aliens and TCUs are my choice for the little guys.

Now on to the topic of this thread... In all honesty, I'm surprised Link Cams aren't more appreciated for the niche that they will hopefully fill. Will they replace standard, symmetric lobed cams? No, they're too heavy and expensive, and don't cover the range you need. But what about throwing in a couple as much more universal anchor or backup pieces? You'll only need a couple, but you don't necessarily know what size they'll be. Why bring 3 cams when one will cover the range? And how about easier alpine routes where you really only want a few cams to supplement your much lighter passive pro? The Link-Cam seems the ideal piece for this with its huge camming range.

Though they're all lumped together as extended range pieces, I don't see the Link-Cam falling into the same category as Super and especially Max cams. I highly doubt anyone will buy a "set" of 6 or 8 link cams, but I'm sure we'll see many folks with full sets of Max Cams. Super Cams seem to fall in between the intent of the other two, filling the niche for the med-large size cams in a set of Metolius cams.


rainontin


Jun 10, 2005, 10:47 PM
Post #38 of 55 (11289 views)
Shortcut

Registered: Mar 4, 2005
Posts: 262

Re: the best new cams [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (0 ratings)  
Can't Post

No mention of the new "shark's fin" teeth on the Super Cam? Supposedly they keep the teeth from getting "lubed up" on grit from the rock when a piece is weighted.


rockdiablo


Jun 10, 2005, 11:30 PM
Post #39 of 55 (11289 views)
Shortcut

Registered: Feb 25, 2002
Posts: 46

Re: the best new cams [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (0 ratings)  
Can't Post

In reply to:
.... maybe you can just get a large range in virtually a unchanged cam, the C4.

No, you don't have to "relearn" how to place it. You don't have to "get used" to virtual axles. Ya don't have to worry about the "steel inner lobes".

Nope, you pretty much use it just like before except it weighs less...

Huh - that was easy.
STFU
you plastic pulling Starbucks swilling OC gym punk


healyje


Jun 10, 2005, 11:53 PM
Post #40 of 55 (11289 views)
Shortcut

Registered: Aug 22, 2004
Posts: 4204

Re: Cam Revolution: Link? Super? or Max? [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (0 ratings)  
Can't Post

In reply to:


I'm not so sure about this.

If the stem is not centered between the lobe contact points, the force in the direction of the stem cannot be equal at each contact point. It must be larger on the side with the smaller lobes. It looks like this is exacerbated even more when the lobes are fully retracted, which also happens to be when the lobe radius (and therefore contact surface) is the smallest.

Still strong enough? Probably, but it definitely performs differently than a standard symmetric lobed cam.

~Adam~

The force exerted on the rock is basically the same on both small and largge opposing cams by virtue of the matched 13.5 degree camming angles and the fact that they share a single axle - the distance from the axle to the rock is irrelavent.


renohandjams


Jun 11, 2005, 12:41 AM
Post #41 of 55 (11289 views)
Shortcut

Registered: May 24, 2005
Posts: 616

Re: the best new cams [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (0 ratings)  
Can't Post

In reply to:
No mention of the new "shark's fin" teeth on the Super Cam? Supposedly they keep the teeth from getting "lubed up" on grit from the rock when a piece is weighted.

Does anyone know more about this? I don't know why the teeth would make a big difference.

----------------------------------------------------------------------------------
-kenny
http://www.TradRack.com
Free Email Account, yourname@TradRack.com, click on the link below to see if the name you want is available:
http://www.tradrack.com/...atalog/freeemail.php[/


mandrake


Jun 11, 2005, 1:03 AM
Post #42 of 55 (11289 views)
Shortcut

Registered: Jan 7, 2004
Posts: 188

Re: the best new cams [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (0 ratings)  
Can't Post

Also, I think that Link cams could have a place at the end of your aiders for crack jugging.


trenchdigger


Jun 11, 2005, 2:35 AM
Post #43 of 55 (11289 views)
Shortcut

Registered: Mar 9, 2003
Posts: 1447

Re: Cam Revolution: Link? Super? or Max? [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (0 ratings)  
Can't Post

In reply to:
In reply to:


I'm not so sure about this.

If the stem is not centered between the lobe contact points, the force in the direction of the stem cannot be equal at each contact point. It must be larger on the side with the smaller lobes. It looks like this is exacerbated even more when the lobes are fully retracted, which also happens to be when the lobe radius (and therefore contact surface) is the smallest.

Still strong enough? Probably, but it definitely performs differently than a standard symmetric lobed cam.

~Adam~

The force exerted on the rock is basically the same on both small and largge opposing cams by virtue of the matched 13.5 degree camming angles and the fact that they share a single axle - the distance from the axle to the rock is irrelavent.

Again, the outward force on the rock is a linear function of the camming angle and how hard you pull on the cam. The force perpendicular to this - the friction force - is dependent on the distance from the stem to the rock. I'll draw up a force/moment diagram for ya tonight.


goodwill


Jun 11, 2005, 4:27 AM
Post #44 of 55 (11289 views)
Shortcut

Registered: Jan 30, 2004
Posts: 28

Re: Cam Revolution: Link? Super? or Max? [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (0 ratings)  
Can't Post

I'm also going to disagree with your physics, Adam.

In reply to:
We're talking about two different forces here.

Assuming a static situation, the net force and moment in the system must be zero.

Agreed.

In reply to:
Now let's set up our coordinate system. Assume the X-axis is the axle of the cam. Assume the Y-axis is the stem of the cam.

For the net force in the X direction to be zero, you're right, both lobes must exert the same outward force.

Exactly. And here's the thing: because the angles of the forces on the left and the right are equal (as healyje pointed out), the ratios of the vertical and horizontal components must be the same for both forces. Because the horizontal components are the same (as you just pointed out), the vertical components must also be the same.

In reply to:
For the net force in the Y direction to be zero, the situation is a bit different. In one direction, you have pull on the stem, and in the other direction, you have friction forces on each of the lobes pulling in the opposite direction.

Because of the nature of the asymmetric lobes, the stem will always be nearer to one side of the crack than the other. How "centered" it is depends on how retracted the lobes are. In every case, though, the smaller lobe will be forced to bear more of the load on the cam.

I agree with all but the last sentence. You give no physical justification for this.

In reply to:
Take for example a placement in a 3" wide crack. Let's assume the stem is offset 1" from one wall (therefore 2" from the other wall) of the crack. Now let's pull down on the stem with 9 lb of force (in the Y direction). The force of friction (Y direction) against the larger lobe will be 3lbf and the force against the smaller lobe 6lbf.

Again, what principle of physics are you basing this on? Sorry, I'm not trying to be mean or anything. I'm just pointing out where exactly the flaw in your logic is.

I just drew up a force diagram myself, and I'm 100% certain that the forces on the two sides of the crack are equal. To summarize:

The fact that the system is in horizontal equilibrium requires that the horizontal components of the two forces be the same. If the camming angle is the same on both sides, then this requires that the vertical components of the forces (which are equal to the friction forces from the left and right sides of the crack) must also be equal.



You might be thinking that the friction forces cause a moment (a torque) on the cam lobes, and maybe that's what you're basing your argument on. But moments are pretty much irrelevant here. Let's consider the right cam lobe. The friction force (pulling upward on this lobe) seems to exert a moment about the cam's axle, but the normal force (the wall of the crack pushing the lobe directly to the left) exerts an equal moment, canceling out the first. The easiest way to see this is to just consider the cam lobe as a straight beam, in compression, going from the cam's axle to the right wall of the crack. Since it's a beam in compression, the force it exerts on the wall of the crack must go exactly in the direction of the beam (namely, to the right, and 13.5 degrees down.) Since the whole system is in equilibrium, the *net* force exerted by the wall of the crack on the beam (the sum of the friction force and the normal force) must be equal to this, but in the opposite direction. So really the only two forces acting on the point of contact between the beam and the rock are exactly in the direction of the beam, and therefore do not induce a moment about the cam axle. Basically, as far as I can tell, there are no moments that are really relevant in this situation.

Will


trenchdigger


Jun 11, 2005, 5:33 AM
Post #45 of 55 (11289 views)
Shortcut

Registered: Mar 9, 2003
Posts: 1447

Re: Cam Revolution: Link? Super? or Max? [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (0 ratings)  
Can't Post

In reply to:
I'm also going to disagree with your physics, Adam.

In reply to:
We're talking about two different forces here.

Assuming a static situation, the net force and moment in the system must be zero.

Agreed.

In reply to:
Now let's set up our coordinate system. Assume the X-axis is the axle of the cam. Assume the Y-axis is the stem of the cam.

For the net force in the X direction to be zero, you're right, both lobes must exert the same outward force.

Exactly. And here's the thing: because the angles of the forces on the left and the right are equal (as healyje pointed out), the ratios of the vertical and horizontal components must be the same for both forces. Because the horizontal components are the same (as you just pointed out), the vertical components must also be the same.

In reply to:
For the net force in the Y direction to be zero, the situation is a bit different. In one direction, you have pull on the stem, and in the other direction, you have friction forces on each of the lobes pulling in the opposite direction.

Because of the nature of the asymmetric lobes, the stem will always be nearer to one side of the crack than the other. How "centered" it is depends on how retracted the lobes are. In every case, though, the smaller lobe will be forced to bear more of the load on the cam.

I agree with all but the last sentence. You give no physical justification for this.

In reply to:
Take for example a placement in a 3" wide crack. Let's assume the stem is offset 1" from one wall (therefore 2" from the other wall) of the crack. Now let's pull down on the stem with 9 lb of force (in the Y direction). The force of friction (Y direction) against the larger lobe will be 3lbf and the force against the smaller lobe 6lbf.

Again, what principle of physics are you basing this on? Sorry, I'm not trying to be mean or anything. I'm just pointing out where exactly the flaw in your logic is.

I just drew up a force diagram myself, and I'm 100% certain that the forces on the two sides of the crack are equal. To summarize:

The fact that the system is in horizontal equilibrium requires that the horizontal components of the two forces be the same. If the camming angle is the same on both sides, then this requires that the vertical components of the forces (which are equal to the friction forces from the left and right sides of the crack) must also be equal.



You might be thinking that the friction forces cause a moment (a torque) on the cam lobes, and maybe that's what you're basing your argument on. But moments are pretty much irrelevant here. Let's consider the right cam lobe. The friction force (pulling upward on this lobe) seems to exert a moment about the cam's axle, but the normal force (the wall of the crack pushing the lobe directly to the left) exerts an equal moment, canceling out the first. The easiest way to see this is to just consider the cam lobe as a straight beam, in compression, going from the cam's axle to the right wall of the crack. Since it's a beam in compression, the force it exerts on the wall of the crack must go exactly in the direction of the beam (namely, to the right, and 13.5 degrees down.) Since the whole system is in equilibrium, the *net* force exerted by the wall of the crack on the beam (the sum of the friction force and the normal force) must be equal to this, but in the opposite direction. So really the only two forces acting on the point of contact between the beam and the rock are exactly in the direction of the beam, and therefore do not induce a moment about the cam axle. Basically, as far as I can tell, there are no moments that are really relevant in this situation.

Will

Ah, I see the point of disagreement here.

Moments are definitely relevant here.

Now the kicker...
Are your cam lobes contacting the walls of the crack (assumed parallel) exactly opposite (normal to) each other? Or is one lobe contacting the crack lower (placed vertically) than the opposite lobe? In which orientation does this cam tend to sit when you place it?


goodwill


Jun 11, 2005, 8:19 AM
Post #46 of 55 (11289 views)
Shortcut

Registered: Jan 30, 2004
Posts: 28

Re: Cam Revolution: Link? Super? or Max? [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (0 ratings)  
Can't Post

In reply to:
Ah, I see the point of disagreement here.

Moments are definitely relevant here.

Now the kicker...
Are your cam lobes contacting the walls of the crack (assumed parallel) exactly opposite (normal to) each other? Or is one lobe contacting the crack lower (placed vertically) than the opposite lobe? In which orientation does this cam tend to sit when you place it?

As stated before, the cam lobes make an angle of 13.5 degrees from the horizontal where they contact each side of the crack. I am assuming a parallel-sided crack. Thus, if the lobes are of different sizes, then they must necessarily contact the rock at different heights. Here's a force diagram:

http://will.is-a-geek.org/.../p6110028_scaled.jpg

Of course the figure is not to scale. I have simplified things by leaving out the walls of the crack, and using straight beams in place of the cam lobes as I mentioned earlier. Note that all of the forces (except the downward force at the cam's axle) are in the direction of these beams (hence the comment about moments being irrelevant), and all of these diagonal forces must have the same magnitude. So unless you are imagining a very different scenario, then your calculations are incorrect.

Will


goodwill


Jun 11, 2005, 9:01 AM
Post #47 of 55 (11289 views)
Shortcut

Registered: Jan 30, 2004
Posts: 28

Re: the best new cams [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (0 ratings)  
Can't Post

I haven't yet added my two cents about all the new cam designs, and I don't want to hijack this thread with physics mumbo jumbo, so here's my opinion if anyone cares.

First off, I don't think that any of these new designs should be dismissed as not being revolutionary and new. I agree with healyje's point that the Max Cam is the only one that is significantly different at the level of basic foundations of the way a cam works, and I'm glad he pointed it out. (I hadn't noticed that before about the Max Cam, and I must say it's the first thing I've heard that might make me think twice about them. I guess I should let them stand the test of time before rushing out to get some. :D ) But I do think that just from the standpoint of engineering, all of these new cams are pretty significant. Some pretty serious design went into these things, and I'm really glad to see such clever products making it to market.

Having said that, I think that the clear winner (just my humble opinion) is the Max Cam. For one thing, the others are really only available in a pretty limited range of sizes, whereas there are six sizes of Max Cams, covering the range from a little over 0.5" to almost 5". In other words, these are the only ones that you could really build a rack out of.

For another thing, if you compare the expansion ranges and weight of these cams, you'll see that the Max Cams are significantly lighter than similar sizes of the other cams. In fact, they're within a few grams of the weight of similar-sized Camalots... lighter in some cases. (I'm looking at tables in the most recent mountaingear.com catalog.) As far as expansion range is concerned, the Link Cams are impressive (significantly greater than 2:1 range) but the Super Cams are really not that impressive. They are no better than even Camalots in this respect. The Max Cams are in the middle here, but they do have a full 2:1 expansion range, which is a significant step up from any previous cam designs. This doesn't mean you carry fewer of them, but rather that there is more overlap in the sizes, which may give you more options for a given placement.

Finally, while I haven't actually handled any of these cams, the Max Cams seem the most ergonomic. This is largely a matter of opinion, but I personally prefer the single flexible stem with a loop at the end (like aliens and the C4 Camalots). I especially have never been fond of the double-stem design, which Metolius uses in all their cams. (If the placement is anything but perfectly vertical, the cables are likely to get kinked if they are weighted. This is especially bad for aiding.)

I hate to come down so hard on the Super Cams, but I have to say that from what I've read and heard, I'm not that impressed. If you can get the same range with a product that's lighter, more ergonomic (in my opinion) and has been around for 20 years, then why choose the Super Cams?

Just my two cents.


renohandjams


Jun 11, 2005, 6:39 PM
Post #48 of 55 (11289 views)
Shortcut

Registered: May 24, 2005
Posts: 616

Re: the best new cams [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (0 ratings)  
Can't Post

In reply to:
I hate to come down so hard on the Super Cams, but I have to say that from what I've read and heard, I'm not that impressed. If you can get the same range with a product that's lighter, more ergonomic (in my opinion) and has been around for 20 years, then why choose the Super Cams?
Just my two cents.

Really? So the Super Cam doens't save any weight or range expansion? What product are you comparing it to? My Vote is with the max cam, but I also think that the Link Cams might come in handy for mixed ice climbs where you might have a limited number of pieces on your rack, so you need something to fit. If the link holds like any other cam (we'll find out in two weeks) then I'll get a pair for routes where I have no idea what I'm up against and I'm limited on the number of cams I can carry because of all the ice and snow gear that I have.

How do you guys think the link cams might do in snow and ice? Any problems with all the moving parts or the steel lobes?

----------------------------------------------
-Kenny
http://www.TradRack.com
Free Email, yourname@TradRack.com, only 100 available.
Click Here To See if the Name you want is available


goodwill


Jun 11, 2005, 10:12 PM
Post #49 of 55 (11289 views)
Shortcut

Registered: Jan 30, 2004
Posts: 28

Re: the best new cams [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (0 ratings)  
Can't Post

In reply to:
In reply to:
I hate to come down so hard on the Super Cams, but I have to say that from what I've read and heard, I'm not that impressed. If you can get the same range with a product that's lighter, more ergonomic (in my opinion) and has been around for 20 years, then why choose the Super Cams?
Just my two cents.

Really? So the Super Cam doens't save any weight or range expansion? What product are you comparing it to?

I'm talking about Camalots here (they're the only "extended-range" cam that's been around for anywhere near 20 years.) The small Supercam is pretty close to a #2 C4 Camalot, and the medium is pretty close to a #3. In each of those cases, the Supercam does have about 2 to 4 millimeters more range than the Camalot, but it's also about 2 mm bigger at the lower end. In other words, really not a big advantage, as far as I can tell. The range of the large Supercam fits completely within the range of the #4 Camalot, so the Camalot beats it just slightly at both the narrow and wide ends. In all three cases, the Camalot is more than an ounce lighter than the corresponding Supercam. To me, there's no contest here.

The one advantage the Supercams might have is their extra wide cam lobes, like the old Metolius Fat Cams. I could see where this might be useful in certain kinds of rock, but I don't think I've ever felt a need for it. Did anyone ever use these things and find that wide surface helpful?

Will


healyje


Jun 13, 2005, 7:52 AM
Post #50 of 55 (11289 views)
Shortcut

Registered: Aug 22, 2004
Posts: 4204

Re: the best new cams [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (0 ratings)  
Can't Post

Call me old school - I still haven't traded my Petzl Spirits for wire gates. But I've never been happy with the Camalot fasteners details or the manufacturing execution on the several large ones I own. I much prefer the manufacturing and burliness of the big Wild Country cams but have some issues with the design of those. And while I'm currently experimenting with some Heliums and 8mm dynemma slings, in general I like burly and personally have seen enough over thirty years to make me [very] wary of the overall drive to save weight past a certain point.

To be honest, between the two I have climbed with so far I'll take the Super Cam on sheer manufacturing excellence alone, and the fact that they don't trade burliness to shave an ounce or two is a decision I respect from a crew that, from what I know of them, climb as hard as anyone and I suspect aren't into dragging around any more weight than they feel is absolutely necessary.

But again, a lot of opinions on gear most folks haven't climbed on - hold'em side-by-side once they're out, climb on them, and then vote with your wallet...

First page Previous page 1 2 3 Next page Last page  View All

Forums : Climbing Information : Gear Heads

 


Search for (options)

Log In:

Username:
Password: Remember me:

Go Register
Go Lost Password?



Follow us on Twiter Become a Fan on Facebook