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Outer Space whipper in Eldo yesterday


Tradiban · · Unknown Hometown · Joined Apr 2004 · Points: 11,510
JNE wrote:

This is incorrect, and to help you out, I bolded all the blatantly wrong parts ;)

Care to explain why?! Oh yea, you can't. Lol. It's my favorite when know-it-alls try the "nuh uh" approach. So convincing!

Take a cam and squeeze into a shallow crack, look at the lobes, then make a standard placement and look at the lobes again. It doesn't take a genius to see how over-cammed lobes don't have the same leverage (or whatever it is) and thus the potential to slide.
Travis S · · Texas · Joined Jul 2018 · Points: 10
Tradiban wrote:

Care to explain why?! Oh yea, you can't. Lol. It's my favorite when know-it-alls try the "nuh uh" approach. So convincing!

Take a cam and squeeze into a shallow crack, look at the lobes, then make a standard placement and look at the lobes again. It doesn't take a genius to see how over-cammed lobes don't have the same leverage and thus the potential to slide.

Its not about leverage, it’s about cam angle

Mark Pilate · · Unknown Hometown · Joined Jun 2013 · Points: 10

Tradiban got cocky on the other thread, jumped to the false conclusion that he was smart, so thought he’d saunter over here to wax all sciencey and stuff...lol. 

PWZ · · Unknown Hometown · Joined Feb 2016 · Points: 0
Tradiban wrote:

 know-it-alls

The ironing is delicious

Marc H · · Longmont, CO · Joined May 2007 · Points: 255
PWZ wrote:

The ironing is delicious

Especially if you’re anemic.

garrett knorr · · salt lake city · Joined Feb 2016 · Points: 85

One thing that always annoys me is that when a new climber posts a question like, "what cams should I buy" or "how is this anchor setup?" They are instantly ripped apart because, "search the forums, this has been discussed before." As if we never cover topics that haven't been discussed before. 

Yet all the self proclaimed "climbing experts" (mtn project regulars) are more than happy to start the exact same debate over stuff that has been rehashed even more than the noob's questions. Ie grigris, rappel v lower, cam angles ect.

highaltitudeflatulentexpulsion · · Colorado · Joined Oct 2012 · Points: 35

Older Trango cams had a point at which they seems to expand slightly near the end of the trigger pull. It didn't cause failures outright but sure caused a lot of shit placements and even more stuck cams.

Go on a roadtrip to trad areas and keep track of the stuck cams. Often they are bullshit like Salewa, Trango, and whatever dog doo you could get from Europe in the late 90's and early aughts.

What does this have to do with the 40 foot whipper? Nothing. Absolutely nothing.

I bet it was 25' tops. Based on reported penis and fish size.

Anthony H · · Seattle, WA · Joined Dec 2011 · Points: 90
Tradiban wrote:

Care to explain why?! Oh yea, you can't. Lol. It's my favorite when know-it-alls try the "nuh uh" approach. So convincing!

Take a cam and squeeze into a shallow crack, look at the lobes, then make a standard placement and look at the lobes again. It doesn't take a genius to see how over-cammed lobes don't have the same leverage (or whatever it is) and thus the potential to slide.

That is just plain wrong. 


The frictional force that is preventing the cam from sliding out is the product of the normal (perpendicular) force and the coefficient of friction. The normal force is a function of the downward force along the axle and the camming angle. Cams since the original Ray Jardine design have been designed with *logarithmic spiral shape, which guarantees constant camming angle no matter how "cammed" your cam is, which in turns guarantees the same frictional force given the same downward force and coefficient of friction.

*fixed name
Suburban Roadside · · Abovetraffic on Hudson · Joined Apr 2014 · Points: 2,089

Guy H. wrote
Not sure how you take a 40 on that pitch...

slim  Wrote· 1 hour ago ·
this is what i would like to know.  good gear on the entire route, unless you choose not to place it.



Saving this
(~)uter space ! !,
(I'LL see if I have any notes)
 Its been 20 yrs but it seems to me that I was able to sew-up that pitch & placed 6 solid cams including 2 #1.5 Frnds & at least a  .75 green (Camalot)
Spaggett, Gotcha! · · Raleigh, NC · Joined Jun 2018 · Points: 0

We're talking about double axle cams here.  Here's why free-body diagram drawing engineers should get out to climb more often.

If 'x' is width of lobes and 'a' is cam angle, dx/da is at a minimum at the fully-cammed (or overcammed) position.  For those of you thinking, "an overcammed has the greatest holding force"; yay! you're right.. but that doesn't mean it's most likely to hold that way.  On the other hand, this is the most difficult position of the cam to engage due to the minimum amount of expansion per cam angle change.  So, if it never engages before it is ripped out, who gives a fuck how good the holding force is.  To add to that, the lobes have the smoothest and largest contact points when it's overcammed, which I always thought was pretty stupid (at least on C4s and friends, dunno about aliens) -- should have more teeth in that position, not fewer IMO.  On sandstone, damp granite, etc, those things will skate right out because there's no teeth to actually catch the rock and start engaging.

So yeah, turns out placement and rock matter.  And you're all sort of right.

Mark Pilate · · Unknown Hometown · Joined Jun 2013 · Points: 10
Anthony H wrote:

.....Cams.....have been designed with an exponential spiral shape....

Almost.  It’s actually logarithmic.  Same, only opposite 

Tradiban · · Unknown Hometown · Joined Apr 2004 · Points: 11,510
Spaggett, Gotcha! wrote: We're talking about double axle cams here.  Here's why free-body diagram drawing engineers should get out to climb more often.

If 'x' is width of lobes and 'a' is cam angle, dx/da is at a minimum at the fully-cammed (or overcammed) position.  For those of you thinking, "an overcammed has the greatest holding force"; yay! you're right.. but that doesn't mean it's most likely to hold that way.  On the other hand, this is the most difficult position of the cam to engage due to the minimum amount of expansion per cam angle change.  So, if it never engages before it is ripped out, who gives a fuck how good the holding force is.  To add to that, the lobes have the smoothest and largest contact points when it's overcammed, which I always thought was pretty stupid (at least on C4s and friends, dunno about aliens) -- should have more teeth in that position, not fewer IMO.  On sandstone, damp granite, etc, those things will skate right out because there's no teeth to actually catch the rock and start engaging.

So yeah, turns out placement and rock matter.  And you're all sort of right.

Boom. Y'all gettin' fucked up on this knowledge!?

Mark Pilate · · Unknown Hometown · Joined Jun 2013 · Points: 10

Well...HE’s wrong.  Wasn’t the cam in question a Trango?  

Travis S · · Texas · Joined Jul 2018 · Points: 10
Spaggett, Gotcha! wrote: We're talking about double axle cams here.  Here's why free-body diagram drawing engineers should get out to climb more often.

If 'x' is width of lobes and 'a' is cam angle, dx/da is at a minimum at the fully-cammed (or overcammed) position.  For those of you thinking, "an overcammed has the greatest holding force"; yay! you're right.. but that doesn't mean it's most likely to hold that way.  On the other hand, this is the most difficult position of the cam to engage due to the minimum amount of expansion per cam angle change.  So, if it never engages before it is ripped out, who gives a fuck how good the holding force is.  To add to that, the lobes have the smoothest and largest contact points when it's overcammed, which I always thought was pretty stupid (at least on C4s and friends, dunno about aliens) -- should have more teeth in that position, not fewer IMO.  On sandstone, damp granite, etc, those things will skate right out because there's no teeth to actually catch the rock and start engaging.

So yeah, turns out placement and rock matter.  And you're all sort of right.

This is for sure wrong. The grooves on a C4 do nothing and the friction force doesn’t change based on surface area, that’s basic physics. Also the expansion per cam angle doesn’t matter either. 


Edit: Just went and double checked my C4s and dragons as well and even at the most over cammed position you still would have grooves and the surface area is not different, even though neither of those things matter
Spaggett, Gotcha! · · Raleigh, NC · Joined Jun 2018 · Points: 0
Travis S wrote:

This is for sure wrong. The grooves on a C4 do nothing and the friction force doesn’t change based on surface area, that’s basic physics. Also the expansion per cam angle doesn’t matter either. 


Edit: Just went and double checked my C4s and dragons as well and even at the most over cammed position you still would have grooves and the surface area is not different, even though neither of those things matter

All very insightful and well supported points.  Force is irrelevant when the lobes never catch -- that was literally the entire point you missed.  Rougher surface is more likely to catch. And if you believe smooth vs rough surfaces do nothing for friction force, I can only assume you have ghastly footwork.

Robert Rowsam · · Grand Junction, CO · Joined Oct 2012 · Points: 175
Travis S wrote:

This is for sure wrong. The grooves on a C4 do nothing and the friction force doesn’t change based on surface area, that’s basic physics. Also the expansion per cam angle doesn’t matter either. 


Edit: Just went and double checked my C4s and dragons as well and even at the most over cammed position you still would have grooves and the surface area is not different, even though neither of those things matter

This guy the only one who knows what he's talking about. The grooves, teeth, sandblasting, of lobes is marketing. Makes little, if any difference in holding power. 

Travis S · · Texas · Joined Jul 2018 · Points: 10
Spaggett, Gotcha! wrote:

All very insightful and well supported points.  Force is irrelevant when the lobes never catch -- that was literally the entire point you missed.  Rougher surface is more likely to catch. And if you believe smooth vs rough surfaces do nothing for friction force, I can only assume you have ghastly footwork.

I feel it is unnecessary to point out the obvious lack of climbing skill I possess. However I do apparently know more about physics than you. 


https://www.mountainproject.com/forum/topic/107076002/overcammed-cams-more-prone-to-slip-out?page=2
Spaggett, Gotcha! · · Raleigh, NC · Joined Jun 2018 · Points: 0
Travis S wrote:

I feel it is unnecessary to point out the obvious lack of climbing skill I possess. However I do apparently know more about physics than you. 


https://www.mountainproject.com/forum/topic/107076002/overcammed-cams-more-prone-to-slip-out?page=2

I was hoping we'd get a link to a prior debate just like this one.  Thanks!

Travis S · · Texas · Joined Jul 2018 · Points: 10
Spaggett, Gotcha! wrote:

I was hoping we'd get a link to a prior debate just like this one.  Thanks!

The significance of that link is that someone asked three of the major manufacturers and they all agreed that it makes no difference except that the cam is more likely to get stuck. Just out of curiosity, do you have any evidence to support your claim asides from made up physics and your superior climbing skills?
Bill Lundeen · · Lee Vining, CA · Joined Nov 2013 · Points: 115

The only cams I've ever seen pop right out like they weren't even in at all in my 25 yrs of climbing have been overcammed units.  If you read the goods put out by SLCD manufacturers they say an optimal placement is from 10% to 50% open.  That means open just slightly to 45 degree angles on the cam lobes.  Overcammed units have no room to expand out to send the force laterally into the rock. 

Guideline #1: Don't be a jerk.

Colorado
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