Discussion Topic |
|
This thread has been locked |
| Messages 1 - 72 of total 72 in this topic |
deuce4
Social climber
Pagosa Springs CO
|
|
|
Topic Author's Original Post - Mar 17, 2005 - 04:56pm PT
|
Anyone used Trango's new MaxCams? Curious as to how they feel in terms of holding power.
I just did a quick study of the cam angles, got 16.5 degrees on the big cam, and 40 degree cam angle (!) on the little narrow one, measuring on the screen and using this formula:
Those are big cam angles for a cam, generally you need a 14.5 degree cam angle, or less, for cams to hold in most rock (assuming a coefficient of friction of .25). Havn't done a force diagram--any other engineers out there have a look at these cams?
http://trango.com/prod.php?id=113
|
|
deuce4
Social climber
Pagosa Springs CO
|
|
|
Topic Author's Reply - Mar 17, 2005 - 05:17pm PT
|
Clearly the effective cam angles will be improved with consideration of the multiple axles, but one would need to sketch up a force diagram, hard to do from just pics--I'd like to see one in person. What looks like will happen is the 40 degree cam will have a lower effective cam contact angle (angle between the rock contact and the center of force--the main axle), but the 16.5 degree cam will have a greater effective cam angle.
|
|
Moof
Trad climber
A cube at my soul sucking job in Nor. CA
|
|
|
Mar 17, 2005 - 05:17pm PT
|
I think you are missing out on what the third axle does. In the case of the large cam, as you pull on the stem, the axle on the big cam moves vertically at a slower rate than the stem. The result is the actual camming angle (relates to ratio of force applied to the stem to the resulting force applied to the rock) is less than that of the cam lobe by itself.
The smaller cam is more complicated with two loaded axles, more than my burnt out brain can handle.
|
|
WBraun
climber
|
|
|
Mar 17, 2005 - 08:25pm PT
|
Real good point John. There’s no mention of any real world experience using them. Just the usual advertising hype.
They are hyping these units as
” This cam is, far and away, the biggest improvement on climbing technology that I’ve seen…”
Gota get some and take some whippers to see.
And Melissa, please edit your post using Larry’s example, thanks
|
|
Shack
Trad climber
So. Cal.
|
|
|
Mar 17, 2005 - 09:26pm PT
|
Deucey,
I think the idea, although I havent played with them yet,
is that the longer cams work more like an adjustable fulcrum point much like having an adjustable Tri-Cam(tm) where you could change the distance betweem the "cams" and the "pivot point".
I AM NOT AN ENGINEER so this may be all wrong!
(just the way it seems to me)
|
|
imnotclever
climber
|
|
|
Mar 18, 2005 - 08:45am PT
|
Perfect sence blinny, I'm glad you posted it.
John, in your experience is the friction factor about .25 for aluminum in contact with rock? Did you test that? Or is that a design value that accounts for things like moist rock, or different types of rock?
|
|
deuce4
Social climber
Pagosa Springs CO
|
|
|
Topic Author's Reply - Mar 18, 2005 - 10:23am PT
|
Mark-
That must be it, the leverage aspect--but only a force diagram will tell for sure.
It looks like a great innovation, simple enough, 2:1 range. Likely on the brilliant scale of things. Makes you wonder....
Surprised it wasn't the buzz a the last trade show, I saw those other funky triple hinged cams, which looked overly complex and prone to problems, but no one really mentioned these MaxCams. Must have been hanging with the wrong crowd.
Looking forward to trying one out sometime.
cheers
ps: imnotclever: the .25 value is a good general low estimate of the coeff. fric., some kinds of rock may be rather higher, easy to test really. The sine of 14.5 is .25:thus the cam angle--see my article on cams for more info http://bigwalls.net/climb/camf/index.html
|
|
imnotclever
climber
|
|
|
Mar 18, 2005 - 12:54pm PT
|
Deuce,
Ive done some pile foundations on rock that have used the friction to resist sliding, granted it is steel to rock, but the values I've used were a little higher. So I'm always interested in what others know about it.
p.s. I've read your article many times and have your site bookmarked. Thanks for both. Some times the log spiral is used in soil engineering, for sliding resistance of retaining walls.
|
|
TomMoulin
climber
Las Vegas
|
|
|
Mar 18, 2005 - 01:16pm PT
|
I too am interested in how these Max Cams feel on the rock.
Quick reference comparison with the C4's:
|
|
Lambone
Ice climber
Ashland, Or
|
|
|
Mar 18, 2005 - 01:23pm PT
|
Does this mean we need new supertopo books with yet another cam range chart?
|
|
mark miller
Social climber
Reno
|
|
|
Mar 19, 2005 - 09:26pm PT
|
Pipe dream ...but any chance the UIAA ( or any other group) could get manufactures of camming units to use the same color coding across a size range? Purple C-4's, Red aliens, orange TCU's and I can't even remeber wild countrys color for that size. Am I just to anal on this or does it make sense to anyone else?
|
|
nature
climber
Flagstaff, AZ
|
|
|
Mar 19, 2005 - 09:43pm PT
|
Mark... if you are anal then so am I. I doubt the color coding thing will fly with the UIAA (I say that as a pure guess). I sent off many of my cams to Misty Mtn. and had them re-sewn with "proper" color coding. It's sorta odd having a blue sling on a green alien - least I'm use to it.
|
|
Moof
Trad climber
A cube at my soul sucking job in Nor. CA
|
|
|
Mar 19, 2005 - 10:05pm PT
|
Them darn offset aliens ALL have grey slings. I wish they just went with the larger color or some such. I almost bought one of them snazzy new gray aliens for kicks, then thought of having an 8th grey sling adding to the alien cluster. I dread the day I have to drag along my gray camalots on something, that'll be 9 cams in similar range with the same damn color.
WC at least is using colors now. Their spectra slings just didn't stick out enough in a sea of rigid friends. Of course my hand crack size pieces now have both an older red/black friend and the new purple, and of course a couple yellow camalots. The combo clashes with my tie dye lycra when I'm dangling off double cross!
I wonder why no one has used brown for their 4+ inch pieces...
|
|
nature
climber
Flagstaff, AZ
|
|
|
Mar 19, 2005 - 10:33pm PT
|
To not be totally off topic, I think I need a closer look at the MaxCam. There is an advertisement in the latest schlock and vice - maybe it's just great marketing but I like the concept of the "floating axle".
I wonder why no one has used brown for their 4+ inch pieces...
coz maybe it'd make it hard to differentiate between your shorts and the #4 on that sick lead?
|
|
vegastradguy
Trad climber
Las Vegas, NV
|
|
|
Mar 20, 2005 - 12:57am PT
|
got to play with one today- although Malcolm wouldnt tell me exactly how the thing functioned from a physics standpoint- i can tell you this much- the cam angle is not determined from the axles. you have to hold it and actually pull the trigger and then you'll see how it works and go..'Oh!'
it feels and works just like a normal cam- with a mutant expansion range. i'm looking forward to their release.
the Metolius Supercam (which i also got to play with) is much weirder in function, and tough to describe. I do think, however, that Trango's design is superior and will perform better in the long run.
|
|
WBraun
climber
|
|
|
Mar 20, 2005 - 01:05am PT
|
To Mr. MaxCam
If you read this post I would like to try your new cam. Would you be so kind to send me some demo to test. I will write some nice result review afterwards.
I will tell everyone I meet about it, unbiased!
Thank you for your time, Werner
|
|
healyje
Trad climber
Portland, Oregon
|
|
|
Mar 20, 2005 - 02:17am PT
|
Having held a SuperCam I can say that I have complete faith in the engineering and design of the Metolius product. It is very much an extension of their existing bombproof cam line and is utterly solid.
I haven't held a MaxCam on the otherhand, and while I have a high regard for Malcolm and team at Trango, I still have significant reservations and questions about the efficacy of any cam-on-cam design, regardless of the manufacturer. I simply have doubts about the resilence of the cam-on-cam link both when subjected to out-of-plane loads and a couple of years of repeated falls and general wear and tear.
The Metolius SuperCam builds on a proven design where Trango's SuperCam design is a fairly radical departure and will need to be validated over time once we all can get our [grubby] hands on some and collectively give them a few thousand real-world flight tests.
|
|
Moof
Trad climber
A cube at my soul sucking job in Nor. CA
|
|
|
Mar 20, 2005 - 01:08pm PT
|
"Having held a SuperCam I can say that I have complete faith in the engineering and design of the Metolius product. It is very much an extension of their existing bombproof cam line and is utterly solid."
Gag. Anyone else note the location...
"I still have significant reservations and questions about the efficacy of any cam-on-cam design"
Any cam on cam design? I was pretty sure there was only one "cam-on-cam design", isn't that the point of getting a patent?
|
|
healyje
Trad climber
Portland, Oregon
|
|
|
Mar 20, 2005 - 07:12pm PT
|
Living in Oregon has nothing to do with my opinions on gear. I've been climbing for 31 years and no one gets a free pass relative to what I'll take a dive on. I have nothing but the highest regard for Malcolm and team at Trango. Ditto for Doug and the Metolius team. It isn't about the people - it's about the designs...
Possibly you simply missed OP's link cam... HOOAP.
|
|
dmitry
Trad climber
Chita, Russia
|
|
|
Mar 22, 2005 - 05:49pm PT
|
Based on TomMoulin's comparison of these with C4 Camalots, the weight and range difference is not overwhelming.
Why pay more for a unit then?
Looks like a novelty.
Moof, your response to the Oregon dude is a disgrace, you sorry Cali thing.
|
|
Melissa
Big Wall climber
oakland, ca
|
|
|
Mar 22, 2005 - 05:55pm PT
|
"Why pay more for a unit then?
Looks like a novelty."
They may be a novelty, but the Max Cams are cheaper.
|
|
dmitry
Trad climber
Chita, Russia
|
|
|
Mar 23, 2005 - 11:10am PT
|
Hey, Melissa, pre C4 camalots and pre "range finder" metolius units are now on various sites and in retail at 1/2 price.
Could be an opportunity to fill out the rack for cheap instead of chasing a new SuperMaxCam at full price :)
|
|
deuce4
Social climber
Pagosa Springs CO
|
|
|
Topic Author's Reply - Mar 23, 2005 - 12:47pm PT
|
After considering the MaxCam, I can see that the only way that the unit will have a consistent force diagram (needed for security in a range of placements, and not just parallel cracks), the relative action of the main cam and the elongated cam will also have to be consistent--not sure how this will work with just springs (as opposed to some sort of direct gearing mechanism not yet implemented on any commercially available cams), but as people have mentioned, the only way to see is to have one in your hands! Still looks like a cool innovation to me.
Maxcam folks, you can send me one too when you send a set to Werner!
|
|
Melissa
Big Wall climber
oakland, ca
|
|
|
Mar 23, 2005 - 01:10pm PT
|
I haven't seen the old camalots for more than 20% off. Where can we get them for 50% off?
|
|
imnotclever
climber
|
|
|
Mar 23, 2005 - 01:41pm PT
|
From the link in JFK's post:
"You can eliminate the need for "offsets"—the extended range of the MaxCam™ takes care of this for you."
Anybody have thoughts on this? I guess it makes sense.
|
|
dmitry
Trad climber
Chita, Russia
|
|
|
Mar 23, 2005 - 04:11pm PT
|
You're right, Melissa, I did a quick search and cannot find anything on-line better than 20-25% off retail on the old camalots either. Saw a much better deal somewhere though...
I got a couple #4's for $40 each at a local rei about a month ago. Check locally, they may be gunning to dump the "old" inventory
|
|
maldaly
Trad climber
Boulder, CO
|
|
|
Apr 13, 2005 - 01:43pm PT
|
Hi Gang,
I finally figured out how to post replies on this forum. The sign up was busted for a while. I forwarded this thread to Max Reed, the designer of the MaxCam (Get it?)and he wrote back:
-----------------------------------------------------
Hi Malcolm,
I saw that thread too and really enjoyed reading it. I love hearing other engineers trying to "figure it out". The solution is not obvious and no one on that thread came very close to it. Solving the geometry was a collaboration of my own efforts with the direction of my advisor in grad school. I dont think I would have ever gotten there on my own.
Whats fun is that no matter what the theory is behind the forces, proof is in the pudding, and the MaxCam bites cracks like a pit bull.
cheers,
Max
--------------------------------------------------------
There are also some informative posts on RC.com by people who have used them. We're scrambling to get production done and they should be availabe in the stores that have ordered them by mid-end of May.
Malcolm
|
|
jfield
Trad climber
dorrington, ca
|
|
|
Apr 26, 2005 - 04:22pm PT
|
My name is John Field, and I am the inventor of the Supercam. I want to avoid making any partisan comments in this forum, but I can inform the discussion.
First of all, the only mathematically consistent definition of range which I know of is the ratio of largest size to smallest size. The original Jardine cams obtained about 1.62. Marketing literature has used a wide variety of different other definitions - mostly spurious.
The supercam is a traditional single axle cam design. A force diagram shows it to be basically identical to Jardine's original cams. By changing the angle subtended by the two cam lobes, it is possible to avoid the tip interference which limits the range of normal cams. At a particular ratio of cam lobe size, this effect is optimized, and this is the supercam. This necessitates a new trigger mechanism, but all the strength loading is as it always has been in the past. The design range is about 1.77, but as discussed below, could have been adjusted up into the low 1.9s or so.
The supercam and the maxcam are not to be confused. The maxcam operates on an essentially new principle. There are important physical assumptions being made in the maxcam which the user should understand and be comfortable with. Range is somewhat over 2.0. There will be no patent problems, and I expect that metolius's pending patent will coexist side by side with trango's. Although completely different in concept, the maxcam has had intellectual property issues with the patent for the camalots. Nonetheless, I believe that it is not infringing the camalot patent, and certainly is outside the original concept of this patent.
Camming range is not simply intrinsic to a design. In addition to advantages of any particular design, there remains a practical decision of the magnitude of the force multiplication - often simply referred to as the effective camming angle. Different manufacturers have chosen different effective 'angles' and this results in significant changes in the range. It also changes the likelihood of a placement holding.
Metolius has traditionally chosen the smallest camming angles. This explains why the range of Metolius units is smaller - traditionally at about 1.60. It also results in a greater outward force, and therefore less friction is required for the placement to hold. Depending on how you look at it, this may be an advantage or a disadvantage. But, no matter how you look at it, it is a choice. The supercams continue in this tradition. I can attest that this choice is made out of concern over safety. Whether you agree with this or not is a matter for your own consideration.
As another example, the camalots use a camming angle at the high end of the manufacturer's range. About 40% of the camalot additional range comes from this, the remaining 60% is from intrinsic advantages of the twin-axle design. Again, this is a choice made by the manufacturer. The obtained range is about 1.72.
Finally, you would be very foolish to assume that the strength ratings accurately represent performance in the real world. While it may seem naively obvious that actual strength of different products would perhaps sort in order with rated strength, this is not the case. Implicitly when you accept a manufacturer's rated strength, you are accepting a whole variety of assumptions about conditions that will actually occur. The strength ratings are only as good as the assumptions which a manufacturer is willing to make on your behalf. But, you are the one living out on the sharp end. Use your head in evaluating these things.
I am currently working on a technical white paper discussing the physics of the supercam and exhibiting the strain patterns in the lobes and testing and so forth. This will be available at the metolius website. In the meantime, I am going to try to field responses privately by email for those interested. You can contact me at jfield@goldrush.com
I guess I need to say that maxcams are a trademark of trango and camalots are a trademark of black diamond equipment.
please climb safely; it is extremely dangerous,
John Field
|
|
WBraun
climber
|
|
|
Apr 27, 2005 - 12:45am PT
|
Thanks for the informative post John.
Werner
|
|
maculated
Trad climber
San Luis Obispo, CA
|
|
|
Apr 27, 2005 - 01:39pm PT
|
I have, in my possession, one #2 Maxcam.
Here is a photo of its placement in Indian Creek:
Not very helpful, but the point is that I have used it, not just looked at it, which is different from when I looked at both the Supercam and the Max Cam at the OR show.
I'm a hard-core BD Camalot lover. It appeals to my sense of solidity, aesthetics, and perceived strength. I like the cam stops for passive protection if the need should arise (walking, etc), I like the flexibility in the stem.
I love the improvements BD has made in the C4. The ergonomic loop and single swage of cable that ensues is great. The lightness is great.
But, okay . . . now, add to that the triple axle, the larger effective range, and the extendable sling and you have the Max Cam. It is every bit as solid in construction as the C4 (which is important to me, and why I don't like other brands of cams with similar components). It comes in the same colors and sizes, even.
It's 100% competition for the C4 and I can flat out say that I would rather have a rack of Max Cams right now that C4s.
They place as easily as C4s, although they are slightly asymetrical so it requires some practice with blind placements, although they can get more tipped out than the Camalot. They feel very much the same ergonomically. I LOVE how the stem pivots, it reacts with that much more "give" on whippers.
The one problem is that when the cam is completely retracted, there is a bit of the lobe that noticably pops out the top. In comparisons with Camalots, this is so markedly obvious because the lobe is cut off instead of completing the circular axis. It does not extend more than .3 inches father than a Camalot would. It's a consideration for shallow pockets, but easily remedies by going a size smaller for your selection. It might be a problem in horizontal placements, but I've not used it in this manner yet.
yes, I have taken whippers on this cam. I rarely take lead falls (I learned it was bad and I can't really get over that head game) but I figured to do this cam justice, I would. Werner, when I get to Yos, I'll look you up if Mal isn't able to give you a test run and show it to you. i cannot say enough good things about this cam.
If you don't find it BETTER than the C4, you will find it equivalent, and as Melissa said, it should be cheaper.
|
|
imnotclever
climber
|
|
I'm going to bring this back up.
From this link http://trango.com/pages/moremax.php they make the statement: "You can eliminate the need for "offsets"—the extended range of the MaxCam™ takes care of this for you."
By referring to Offsets, they must be referring to Hybrid Aliens, so I checked it out. The range on the smallest Max cam is 17.8 to 35.6 mm. The range of the largest Hybrid is 15.5 to 33 mm. So it looks like you could only replace one of the Hybrids with a Max.
Does WC still make offsets and what sizes are they?
|
|
macgyver
Social climber
Oregon, but now in Europe
|
|
Just my 2 cents...
I had two WC offset cams, on loan, late last year. They correspond with the two sizes above a red/yellow alien. I wanted to see if they would make a nice piece for boxed out pinscars etc.
My findings are this:
Pros:
the offset cam is good in flaring knobby grooves (like those found on runoffs of conglomerate rock)
the offest cam is very good in fractured alpine terrain
Cons:
the spacing of the lobes make the flare angle a little severe compared to what you find in pinscars
the depth of the unit makes it pretty clutzy to get solid placements in pin scars. The alien design is ideal for this.
If I bought one I would buy the one above the red/yellow and thats it. Above this the offset angle is pretty big in my opinion.
I did find however that if you climb all the time in blocky/fractured rock the offset placements are left and right thanks to the geological jenga came that seems to occur at higher altitudes. For example I used the cams on some of the shattered routes on the Index in Chamonix and found them to fit all over the place. However i would have had no problem without them.
I wouldn't mind if someday CCH released the red/orange offset....hmmmm a climber can dream.
McG
|
|
imnotclever
climber
|
|
A red-orange would get you from 19.8 to 40.6 mm. The .75 Max cam is 20.3 to 40.6 mm.
|
|
Karl Baba
Trad climber
Yosemite, Ca
|
|
This thread is so fantastically useful, informative and counter to the spirit of so many internet forums, I'm tempted to post a bunch of pictures of Bush morphed into a chimp or Kerry looking like a horse just to break the good karma!
but I won't THanks guys for the input.
Karl
|
|
maculated
Trad climber
San Luis Obispo, CA
|
|
STFU N00B!
Man, that's the first time I've ever used that joke. I promise I won't every again. I feel dirty just typing it.
|
|
dmitry
Trad climber
Chita, Russia
|
|
Just looked at the specs for MaxCam's & SuperCams versus Camalots.
I saw NO advantage weight or usable range wise on the SuperCams vs Camalots. No advantage pricewise either.
While Maxcams are a bit cheaper, I found NO advantage weight or usable range wise vs Camalots, until you get to the biggest #4 purple piece. That one looks like it comfortably covers old BD 3.5 to over 4" range. Could be a great "just in case" OW piece for adventure and alpine climbing.
New Camalots:
Size Color Range(mm) Strength(kN) Weight(gm)
.4 Gray 15.5 - 26.6 10 82
.5 Purple 19.6 - 33.3 12 97
.75 Green 24.1 - 40.9 14 116
1 Red 30.2 - 52.1 14 134
2 Yellow 37.3 - 64.3 14 158
3 Blue 50.8 - 87.4 14 201
4 Gray 66 - 114.3 14 278
5 Purple 85.6 - 148.1 14 381
6 Green 114.3 - 194.6 14 557
MaxCams:
Size Color Weight (g) Range (mm) Strength (kN)
0.5 Purple 85 17.8-35.5 13
0.75 Green 114 20.3-40.6 13
1 Red 132 25.4-50.8 13
2 Yellow 150 33-66 13
3 Blue 201 43.2-86.3 13
4 Purple 280 61-124.5 13
SuperCams:
Size Range (mm) Weight (g) Strength (kN)
Small 39.5 - 70.5 198 13.3
Medium 52.5 - 91.5 255 13.3
Large 66.5 - 118.5 312 13.3
Draw your own conclusions.
|
|
Brian Hench
Trad climber
Seattle, WA
|
|
|
Jan 12, 2006 - 05:10pm PT
|
Let me point out something that sets the MaxCam apart from the Camalot and the SuperCam. Calculate the overlap between sizes, defined as the ratio of the overlap of a given cam size with its next smaller size, divided by the range. In Camalots, it ranges from 37-59%, SuperCam 46-48% and MaxCams 40-72%. You will find that the MaxCam has larger overlaps between sizes as you go down in size. The ratio is about the same as Camalots in the largest size, but is as much as 30% larger in the smaller sizes.
In my experience, it is harder to judge sizes precisely as the size decreases, so having this increased overlap is desirable. It means that chances are, all things being equal, you are more likely to grab size that will fit.
|
|
Trashman
Trad climber
SLC
|
|
|
Jan 12, 2006 - 05:20pm PT
|
if you climb frequently in the desert though, this "useable" range is reduced. if a max cam is more than half open and walks, the asymetry causes one side to tip out progressively more w/ each "walk".
this means the cams are only safe when placed tightly enough to avoid tipping out the "floating" side. it's hard to describe, but easily demonstrated in a wide #2 camalot crack like incredible hand crack in IC. i don't think this would be an issue in most areas, but it certainly affects desert rats.
|
|
Brian Hench
Trad climber
Seattle, WA
|
|
|
Jan 12, 2006 - 05:27pm PT
|
Are you saying that this is more of an issue on fine grained rock like sandstone, compared to, say, granite? In other words in sandstone there is no range advantage.
|
|
Trashman
Trad climber
SLC
|
|
|
Jan 12, 2006 - 05:31pm PT
|
i'm thinking it has more to do w/ the parallelity(not sure if that's a word) of the crack. if you have any constrictions it would appear to stop this. if the crack is expansion joint uniform, the leverage transfers to the sides unevenly and the floating side tips over sideways while the directly attached sides remains in contact.
for a visual, picture an old tech friend, w/ the heads rotated 90 degrees(instead of a flat plane at the lobe bottom running perpendicular to the stem, it runs parallel)
|
|
billygoat
climber
|
|
|
Jan 13, 2006 - 01:09am PT
|
I used the yellow (#2 I believe) max cam for most of last summer. Initially I was impressed, but I came to find it floppy and wiggly. I do believe it has the potential the flop right out of the crack. Well, actually, it did this to my friend on leaning tower (or it had begun to). So unfortunately, I must recommend against their use.
I you hold one, you'll see what I mean. Play with the heads, and notice how they can pivot. It's not cool. They should be made more rigid. I honestly believe this is not a safe device.
|
|
lazide
Big Wall climber
Bay Area, CA
|
|
|
Jan 13, 2006 - 03:30am PT
|
I bought one (the #2) to help fill in my free climbing rack, and with long slings (it walks quite a bit!) it was nice as a second piece in the nice tight hands/cupped hands range, and I liked it.
I took it aid climbing on a couple grade V's, and it was all good - until I did a 'dyno from your top steps to plug in the cam in' move, and... got it stuck.
Like really stuck...
Like i've never ever, EVER gotten a cam fixed before, but this one was fixed stuck.
The floppy stem, coupled with the odd axle geometry seems to make it easier to really get it wedged in like you wouldn't believe.
Other than that, did well. Didn't even spit out in my face when I placed it in a flaring wet pod and stood on it. (boy was I glad!).
|
|
healyje
Trad climber
Portland, Oregon
|
|
|
Jan 13, 2006 - 06:13am PT
|
"I honestly believe this is not a safe device."
I don't think that is really a fair assessment of this product.
If your expectation for Max Cams was that it perform the same as a typical symmetric cam then I can understand you may not be happy with some of their other attributes. These asymmetric cams are not your typical cam beyond the fact that you pull a trigger bar and that when you do cams retract; but the similarity pretty much ends there. To my way of thinking these are more of a specialized device not unlike hybrid/offset cams. And like hybrids you have to understand their limitations and unique advantages.
The instructions that come with the units explicitly warn against pushing them further into a crack once placed - if you want a different placement, then retract the cams and re-place it. Do not attempt to push them deeper, or into a different position, as they will likely respond by "tipping" over the cam tips. With regards to walking, Max Cams don't walk any more (as in more often or on its own) than a symmetric cam, but their asymmetric design does "ratchet" in a way that makes it walk more efficiently when it does. This can also "tip" the cams if they walk too far. But just like any other piece of pro, the Max Cam needs appropriate slinging to insure it is not subjected to the movements of the rope.
Realistically Max Cams are probably not going to be for everyone and I personally wouldn't recommend them for anyone who wasn't already an experienced trad climber. But they have their place, particularly given Alien Hybrids are small and Wild Country discontinued their larger Offsets. And while I might not use them for my primary cams they definitely have a versatile role to play as additional arrow in your quiver. You just have to put the time into understanding how they work and how you can best utilize their unique advantages.
|
|
Trashman
Trad climber
SLC
|
|
|
Mar 28, 2006 - 10:32am PT
|
. . .and disadvantages
if you can ensure that you'll never "kick" a cam on the way past, go for them. personally, i kicked 2 metolius and a camalot this weekend, and was really glad i didn't have to get another piece in to be solid. as Stymy said in the other thread, it only takes about 2 moves to knock them out.
i know you have to runner cams, and none of us ever clip them short when we're gripped, so it's not an issue, right?
|
|
poop*ghost
Trad climber
Denver, CO
|
|
|
Mar 28, 2006 - 11:21am PT
|
I've been using the larger size MaxCam for the last 8-9 months and I've noticed what you're talking about, but I do use runners and so it's not been a problem.
Ulitmately all gear has +'s and -'s, and in this case the HUGE + is that the range is fantastic. I leave it on my rack as a last piece so I have an extremely versatile size towards the end of the pitch, when I've got slim pickens left over.
I would not suggest that somebody rack up 15 of these and head to indian creek. I think there are better suited cams for that business.
|
|
Bart Fay
Social climber
Redlands, CA
|
|
|
Mar 28, 2006 - 03:03pm PT
|
As an interesting aside have a look at U.S. Camming Gear patents.
Follow the chain of related patents.
http://tinyurl.com/erl3j
|
|
Splater
climber
Grey Matter
|
|
|
Mar 28, 2006 - 04:06pm PT
|
It seems that if Metolius made a Ultralight version of the
Supercam, it would weigh less than the equivalent MaxCam or C4.
|
|
Brutus of Wyde
climber
Old Climbers' Home, Oakland CA
|
|
|
Mar 28, 2006 - 06:13pm PT
|
Trango is issuing a recall on #1 Maxcam batch numbers 0605 and 0705.
Brutus
|
|
Cuckawalla
Trad climber
Grand Junction, CO
|
|
|
Mar 28, 2006 - 06:21pm PT
|
Nice To see Someone from lil ol' Pagosa Springs talking.
|
|
Apocalypsenow
Trad climber
Cali
|
|
|
Mar 29, 2006 - 01:38pm PT
|
I have had some good discussions with the engineer who designed the Metolius Max Cam. Highly superior to the Trango...from what I can tell.
|
|
Trashman
Trad climber
SLC
|
|
|
Mar 29, 2006 - 01:48pm PT
|
Quoted from the recall thread, M.D. wrote
"billygoat et al,
Just like all manufacturers, when we list the range of a cam, we list the absolute range. That's the width when it's fully retracted and the width when it's fully expanded. We, along with other manufacturers, say that the useable range is less and reccommend that a cam be placed only in the lower half of its range. This is consistent with what other manufacturers recommend as well. When you take all that into account we still have a higher useable expansion range than all other cams except the OP Link cam.
Mal"
following advice and continuing this over here.
as i've said before about this issue, unless you climb in the desert frequently, or a place w/ splitter basalt cracks, you'll likely never notice this issue.
most manufacturers do recommend a conservative placement, but this tends to be related to the possibility of rock failure(i.e. one aspect of the placement crumbles when loaded, there is range to fill in this void).
in this case, the limit relates to a different mode of failure. as stated by others, if this cam walks while less than halfway retracted, even if there is little to no variation in crack size, the asymetry of the cam causes one side of the cam to tip out. Ron's misunderstanding of the issue on the recall thread highlights the fact that this situation is not common knowledge yet. Ron, if you get a couple of units, test this idea out over at Watts crack, this isn't the same old walking issue.
edit:wow, way too young for this much memory loss, guess i should have re-read the thread, made the same arguement a few months ago.
|
|
That Darn French Guy
Sport climber
Santa Clara, CA
|
|
|
Apr 19, 2006 - 06:52am PT
|
Besides being the proud owner of a 0705 batch maxcam and a handful of dotted aliens (woopee!), I got comments on Maxcam's usage:
 They do tend to be set wrong more easilly, the small lobe tends to be easilly set on it's top 1/2 of it's range while the big one is set on the bottom 1/2 of the range. That means if the cam opens, the small cam lobe will reach the end of its range sooner.
=> In a blind or corner placement, placing with the stem side away from you helps getting the placement right the 1st time.
They do tend to flip sideways when walking. 2/3 weeks ago, at IC, one of my friends used the #2 as a 1st piece, bud did not extend it (not even the double sling). After being jostled by the rope during the full ascent, it flipped. (Note he's an experienced trad leader). Well I pulled the cam out when I got up hanging on a camalot... It took me 15 minutes, and it was possible only because there was enough room to slide my nut tool where the lobes press against the wall to slide them (otherwise they bite the rock). The crack width was a perfect #2...
=> Walking for this cam is an issue. Always extend the sling or use a trad draw (ie sling + biners, not a dogbone sport draw).
General issues:
=> My friends don't like them, because they don't trust them.
=> I can't give them to someone who doesn't know how to use them
=> In a critical situation I may have to rely on a one-shot bad placement?
Bottom line:
I don't think the extra range is worth all those constraints.
I am actually not convinved the MaxCam's usable range is significantly different from a C4.
And I'm bummed about that because I think the cam's well built.
Sonyhome-
|
|
Scared Silly
Trad climber
UT
|
|
|
Apr 19, 2006 - 11:50am PT
|
That Darn French Guy's comments are similar to some others that I have read over on rc.com especially his concerns over setting the cams in critical situations and having to know how to set a cam.
That said folks might want to read the instructions for Max Cams
http://www.trango.com/pdfs/MaxCamIns.pdf
and note the highlighted text:
"All placements MUST be in the lower 1/2 of the expansion range [Figs 1&2].
Then read the next one:
"Never allow your cam to "walk" into the crack or rotate once it is placed."
As others have noted above and in rc.com when the Max cams are placed in the upper 1/2 of the expansion range and walk the lobes with invert with in a few swings and they seem to walk more easily than other cams on the market. YMMV.
|
|
That Darn French Guy
Sport climber
Santa Clara, CA
|
|
|
Apr 20, 2006 - 12:32am PT
|
Well, the biggest criticism is that if people I climb with don't want to use the came because they don't feel safe, then it's a wasted piece. Even if I train myself to place it perfect blindfolded.
And that is a huge consideration...
Just like loaning a car with a tricky clutch or difficult brakes, or a souped up rice rocket with too much torque to an unsuspecting friend.
|
|
Shu Pong
climber
Arlington, Washington
|
|
Here is a free body diagram of the max cam. It is not very accurate dimensionally but it illustrates the concept of how the small cam makes up for its high geometric cam angle.
The small cam can be defined as a three force member and the large cam can be defined as a two force member.
When a two force member is in a state of equilibrium, its two forces must be equal in magnitude, opposite in direction and be concurrent, or lined up.
When a three force member is in equilibrium its three forces must add up to zero, and the sum of the moments must also add up to zero, this means that the three forces must be either parallel(they're not in this case), or they must be concurrent(their lines of action must intersect at a single point). Looking at the small cam, the falling force is known to be downward and the force at the main axle must be in line with the axle force from the large cam. This means that the contact force (the vector sum of the friction and normal forces of the small cam) is the third force and it must line up with the point where the other two forces intersect. In the drawing you can see that the angle of the contact force on the small cam is at an angle that looks like a very conventional cam angle(much less than its geometric cam angle). What this shows is that there is enough normal force to generate the required friction force for the normal friction coefficients of rock and aluminum.
In the lower drawing, the cam is compressed to nearly 100% and even though the offset arm where the stem is attached is nearly straight above the main axle, the geometry still provides for the contact force to be at an effective angle even thought the geometric cam angle is still steep in the 40 degree range. Whether or not the small cam has a variable cam angle or not, I have no idea. I have not had the opportunity to see one of these cams or get any measurments from one. These drawings simply illustrate the fact that the offset arm on the small cam gives it an effective cam angle that is much smaller than the geometric cam angle.
I'm not a climber and have absolutely no experience setting any kind of cam in a crack and trusting my life to it. I am just an engineering student and I had a class assignment to analyze one of the more conventional cams, and as I was surfing around looking for info I saw this forum. Just thought I would add my two cents worth for anyone who is interested.
|
|
healyje
Trad climber
Portland, Oregon
|
|
Nice work and drawings, thanks...
|
|
pyro
Trad climber
Ventura
|
|
Deuce is the king.
Tx's JM.
cool man style!
|
|
bachar
Trad climber
Mammoth Lakes, CA
|
|
Deucy!
You say a 14.5 degree tangential angle is needed assuming a .25 coefficient of friction to hold in most rock. Are there any charts that list the tangential contact angle of the various cams on the market? What types of rock / cracks have less than a .25 coefficient of friction against most aluminum?
"Materiam superabat opus" bro! jb
|
|
Tom
Big Wall climber
San Luis Obispo CA
|
|
This is my take on the equation for an exponential spiral, which differs from John's by the use of the tangent function, instead of the sine function.
EDIT:
Here's the exponential spiral:
|
|
Brutus of Wyde
climber
Old Climbers' Home, Oakland CA
|
|
"They do tend to flip sideways when walking. 2/3 weeks ago, at IC, one of my friends used the #2 as a 1st piece, bud did not extend it (not even the double sling). After being jostled by the rope during the full ascent, it flipped. (Note he's an experienced trad leader). Well I pulled the cam out when I got up hanging on a camalot... It took me 15 minutes, and it was possible only because there was enough room to slide my nut tool where the lobes press against the wall to slide them (otherwise they bite the rock). The crack width was a perfect #2... "
I had a #0.5 flip as well, as a result of pushing the cam deeper into the crack... Reset it, on lead, using the nut tool in the outside holes of the trigger bar. It was far easier to clean this cam than any other I have ever skewqed up a placement with. the trigger bar holes are a beautiful feature I would like to see on more cams.
Brutus
|
|
healyje
Trad climber
Portland, Oregon
|
|
Yeah, once you place a Max Cam it is imperative that it not move - they have to be slung appropriately or they will like end up in a less than desirable state after any jostling. They likewise should never be "pushed" further or adjusted after placing one. If you want it somewhere or someway different then pull it and re-place it. They have some unique attributes but you can not and should not treat them like a typical symmetric cam.
|
|
Shu Pong
climber
Arlington, Washington
|
|
That whole tangent sine thing made me start thinking. because they can't both be right. So I first tried to figure it out mathematically, before I finally realized that I have no idea how to do it that way. So I used matlab to make a plot of one spiral using tangent(red) and another spiral using sine(blue). At first I did it with a 15 degree cam angle, although it's obvious that they are not the same, it's still hard to tell which one is right. So I bumped up the cam angle to 45 degrees and suddenly it becomes quite obvious that tangent is definitely the correct function to use. If you use sine it is still a logarithmic spiral but it does NOT have the cam angle that you think it does.
The plot below is generated with the equation:
r = e^(mθ)
m is the trig ratio we use to input the cam angle
I used m = sin45 for the blue spiral and
I used m = tan45 for the red spiral
At 45 degrees, the two are different enough to easily see which one really has a cam angle of 45 degrees
What we find is tangent wins, the blue one is still a good curve but it actually has a cam angle of about 35.26 degrees, not 45.
The problem is when you are down in the 13-14 degree range the difference between tangent and sine is quite small and hard to notice the difference.
In the first post there are some measurements for the max cam that come out to a 40 degree cam angle on the small cam and 16.5 on the large one. This means the actual cam angles would be in the neighborhood of about 32.7 degrees and 15.8 degrees. You can see how much smaller the difference is for smaller cam angles.
It's funny because I was using sine also, it was the formula given in my a*#ignment. I just finally figured this out last night and my assignment was due today. It didn't actually make much difference in the assignment, so not much to redo, but I showed the prof who promptly spent the first 10 minutes of class studying the plot I had given him.
So thanks Tom for posting your formula or I probably never would have noticed the error.
|
|
Tom
Big Wall climber
San Luis Obispo CA
|
|
|
Jun 10, 2006 - 08:34am PT
|
That whole tangent sine thing made me start thinking. because they can't both be right.
No, they can't. The difference between the sine and tangent of 14 degrees is about 3%. Using the sine would result in a smaller camming angle than what was intended; the tangent of 13.6 degrees equals the sine of 14 degrees. Similarly, if you take the sine of 45 degrees (0.7071) and then take the arctangent, you get 35.2644 degrees, in accordance with Shu Pong's diagram above.
The correct equation uses the tangent of the angle, not the sine. This can be seen by deriving the equation from first principles; all that is required is we define the curve to have a constant radius-to-tangent angle for the entire curve. When we do that, the exponential spiral results. And the tangent of the angle appears as the constant (shape defining) parameter.
Refer to my earlier post, for a diagram showing how the variables are defined.
The first equation below is valid for any 2-D plane curve expressed in polar coordinates, regardless of whether the radius-to-tangent angle is a constant, or it varies. Also, if deriving this equation from scratch, it would be a rather subtle mistake to use the sine function instead of the tangent function.
Notice that for the special case of the radius-to-tangent angle being 90 degrees, the tangent function becomes infinite, the exponent in brackets becomes zero, the exponential function (e^0) becomes one, and the radius is a constant for the entire curve - a circle.
|
|
deuce4
Big Wall climber
the Southwest
|
|
|
Topic Author's Reply - Jun 13, 2006 - 12:23am PT
|
Here's an article of mine explaining constant camming angle cams (written when I was more of a geek):
http://bigwalls.net/climb/camf/index.html
(I just reworked the webpage as the original html code was from the early 90's and the illustrations did not appear correctly-fixed now). Note: still haven't fixed the superscripts in the text--see the illustrations for proper format of the equations.
Back in the day, I did study friction of various rocks, and found that generally granite had a coefficient of friction with aluminum of well over 0.30, and typically, if I recall correctly on the order of 0.32 or more. Sandstone was hard to measure as there are shear planes associated with the granular stucture, but the friction (with aluminum) was generally lower. Walt and I did some tests in Sedona one year with various alloys, when we also tested an assortment of sandstone bolts with my hydraulic puller.
It turns out mining engineering texts are a good reference for the frictional characteristics of rock, as many of the spring bolts used for mining are dependent on friction.
What happened after the era of Friends is that manufacturers started to play with variable cam angles (ones that varied along the arc of the cam) in order to increase range. I think Metolius were the first to experiment with this technique.
ShuPong's illustrations are nice and look like they're drawn by a fine engineer.
hope this helps
cheers
JM
|
|
Makwizard
Trad climber
durham
|
|
|
Oct 16, 2008 - 05:32pm PT
|
I am currently conducting research at Duke University to analyze and redesign cam lobes. The end goal is to improve a cam's ability to hold in soft rock and flaring cracks. I have just begun my research but will be continually posting updates of my findings on my [url="http://www.duke.edu/~mak25/research.html"]cam research page[/url].
Thanks.
[url="http://www.duke.edu/~mak25"]my homepage[/url].
|
|
couchmaster
climber
|
|
|
Oct 16, 2008 - 11:18pm PT
|
Looking forward to it!
Thanks
|
|
reallyy big star
Social climber
some, place
|
|
|
Feb 12, 2018 - 06:16am PT
|
the free-body diagram of my soul
requires words, no lines or greek symbols:
my destiny is a vector;
normal to my dreams.
thus god recalled my soul;
but no one turned it in.
for all whom employ it
in its broken state
enjoy a pleasingly misguided journey.
|
|
| Messages 1 - 72 of total 72 in this topic |
|
SuperTopo on the Web
|
Let us know!