Forums: Climbing Information: Gear Heads:
Cam on limestone
RSS FeedRSS Feeds for Gear Heads

Premier Sponsor:

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


Hexciter


Jan 12, 2010, 2:36 AM
Post #1 of 34 (17772 views)
Shortcut

Registered: Jan 9, 2010
Posts: 7

Cam on limestone
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (2 ratings)  
Can't Post

While surfing over net, I read comment for cam physics on limestone in forum of DCU Rock Climbing Club.

- CAMMING ANGLES -
Basically avoid Black Diamond Camalots if you
ever plan on climbing on limestone. All camming devices use the basic
logarithmic camming angle of 12.75 Degrees from normal except Black Diamond! Camalots are designed to give a larger expansion range per device, to do this they use a different camming angle that diverts the force of a fall more downwards and less outwards (towards the crack walls) (and they use 2 axels). this means that camalots will pull, Rip, pop-out much more easily on rock with lower coeficents of friction - e.g. limestone. All friends require extra care when being placed on limestone but camalots even more so and should be avoided. they work well on sandstone and granite though. And if you dont want to climb on limestone you're missing out!

Source is:
https://www.redbrick.dcu.ie/~climbing/phpBB3/viewtopic.php f=6&t=225&st=0&sk=t&sd=a&sid=c7f78c4ed5f4c431b2b9683510ccb960&start=15

He made a mistake that camming angle of Friend should be 13.75 degree as patented by Jardine, not 12.75.

What's your opinion? Does it make so much difference?


sungam


Jan 12, 2010, 3:09 AM
Post #2 of 34 (17757 views)
Shortcut

Registered: Jun 24, 2004
Posts: 26800

Re: [Hexciter] Cam on limestone [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (0 ratings)  
Can't Post

WC - 13.75
CCH - 16
Metolius - 13.25 (I believe)
BD c4 - 14.5
(really) old c4's - 14.97
OP link cams - 13.5
DMM 4cu - 13.75
Trango flex cams - 14

These are not definitely true, just what I picked up from websites. Anyways, you can see there is a large range of camming angles used, with aliens having the highest and metolius cams having the lowest. If anyone sees an error in my list, feel free to correct.

Edit to add trango and DMM.


(This post was edited by sungam on Jan 12, 2010, 3:21 AM)


granite_grrl


Jan 12, 2010, 4:38 AM
Post #3 of 34 (17729 views)
Shortcut

Registered: Oct 25, 2002
Posts: 15084

Re: [Hexciter] Cam on limestone [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (3 ratings)  
Can't Post

My opinion: I don't trust any cam in a parallel sided crack in limestone. BD might be the worst, but I wouldn't expect much from any brand. When I place a cam in limestone I am looking for scoops or some sort of other constriction to place them in, but most of the time I'm happier with a hex.

Here's the story of the hubby meatdeacking: http://www.rockclimbing.com/...ssy%20talus;#1708704


Partner j_ung


Jan 12, 2010, 5:54 AM
Post #4 of 34 (17690 views)
Shortcut

Registered: Nov 21, 2003
Posts: 18690

Re: [granite_grrl] Cam on limestone [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (0 ratings)  
Can't Post

^
+1 on that. Slick rock scares the hell out of me.


Partner camhead


Jan 12, 2010, 6:02 AM
Post #5 of 34 (17681 views)
Shortcut

Registered: Sep 9, 2001
Posts: 20939

Re: [Hexciter] Cam on limestone [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (4 ratings)  
Can't Post

LIMESTONE WANTS BOLTS!




kennoyce


Jan 12, 2010, 6:55 AM
Post #6 of 34 (17646 views)
Shortcut

Registered: Mar 6, 2001
Posts: 1338

Re: [Hexciter] Cam on limestone [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (0 ratings)  
Can't Post

Sungam's post looks spot on to me. Aliens certainly do have the largest camming angle and would be the most likely to pull in limestone, and of course metolius has the smallest camming angle and might possibly hold in limestone all though I wouldn't count on it.

As Camhead said, limestone needs bolts. One time I was sport climbing on limestone with a noob who was asking me about trad climbing. I happened to have a small rack in my bag that I had forgotten to take out, so I proceded to place a DMM 4CU (13.75 degree cam angle) in a nice parallel crack at medium expansion range. I wanted to show the noob how a cam works so I gave it a but of a tug only to watch it rip right out of the crack. Needless to say, I don't think it convinced him that trad climbing is indeed safe. Moral of the story is that cams in parallel sided limestone = R/X.


atlnq9


Jan 12, 2010, 10:40 AM
Post #7 of 34 (17490 views)
Shortcut

Registered: Sep 9, 2007
Posts: 111

Re: [Hexciter] Cam on limestone [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (1 rating)  
Can't Post

Metolius Fat cams are what you want. Larger surface areas touching the rock.


geezergecko


Jan 12, 2010, 11:40 AM
Post #8 of 34 (17442 views)
Shortcut

Registered: Mar 26, 2002
Posts: 729

Re: [Hexciter] Cam on limestone [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (0 ratings)  
Can't Post

Aw nuts! Frown


guangzhou


Jan 12, 2010, 4:38 PM
Post #9 of 34 (17362 views)
Shortcut

Registered: Sep 26, 2004
Posts: 3389

Re: [geezergecko] Cam on limestone [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (0 ratings)  
Can't Post

I climb and place cams in limestone a lot. Placements in limestone come down to experience, like any other placement.

I prefer nuts and hexes in limestone, but that is true of any rock. I use what ever gear works for that specific placement.

My two cents.


Partner climboard


Jan 12, 2010, 5:20 PM
Post #10 of 34 (17326 views)
Shortcut

Registered: Apr 10, 2001
Posts: 503

Re: [camhead] Cam on limestone [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (2 ratings)  
Can't Post

camhead wrote:
LIMESTONE WANTS BOLTS!

I'm all for keeping bolts to a minimum on most rock but after climbing Rockies limestone I agree with this!


guangzhou


Jan 13, 2010, 10:02 PM
Post #11 of 34 (17195 views)
Shortcut

Registered: Sep 26, 2004
Posts: 3389

Re: [climboard] Cam on limestone [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (1 rating)  
Can't Post

climboard wrote:
camhead wrote:
LIMESTONE WANTS BOLTS!

I'm all for keeping bolts to a minimum on most rock but after climbing Rockies limestone I agree with this!

I have to agree, every cliff has different needs when it ocmes to protection. Some limestone is suitable for gear lines, others need bolts.


patto


Jan 11, 2011, 2:32 PM
Post #12 of 34 (16225 views)
Shortcut

Registered: Nov 14, 2005
Posts: 1453

Re: [sungam] Cam on limestone [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (0 ratings)  
Can't Post

sungam wrote:
BD c4 - 14.5

I seem to remember C4s being 15. A quick google is non conclusive with many saying 15 and many saying 14.5.

I seem to remember adatesman measuring the cam angle and calculating it to be 15.

atlnq9 wrote:
Metolius Fat cams are what you want. Larger surface areas touching the rock.
That wont help except in the case of rock crushing. More surface area does not mean more friction!


rtwilli4


Jan 11, 2011, 5:32 PM
Post #13 of 34 (16135 views)
Shortcut

Registered: Feb 14, 2008
Posts: 1867

Re: [patto] Cam on limestone [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (0 ratings)  
Can't Post

patto wrote:

atlnq9 wrote:
Metolius Fat cams are what you want. Larger surface areas touching the rock.
That wont help except in the case of rock crushing. More surface area does not mean more friction!

I'm no scientist but it would seem that more surface area would mean just that... more friction. Am I wrong?


guangzhou


Jan 11, 2011, 6:57 PM
Post #14 of 34 (16099 views)
Shortcut

Registered: Sep 26, 2004
Posts: 3389

Re: [rtwilli4] Cam on limestone [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (0 ratings)  
Can't Post

rtwilli4 wrote:
patto wrote:

atlnq9 wrote:
Metolius Fat cams are what you want. Larger surface areas touching the rock.
That wont help except in the case of rock crushing. More surface area does not mean more friction!

I'm no scientist but it would seem that more surface area would mean just that... more friction. Am I wrong?

In this case you're wrong. With cams, more surface is only part of the issues. Hardness of the material plays a bigg role on the holding strength of the cam too.


patto


Jan 11, 2011, 7:09 PM
Post #15 of 34 (16093 views)
Shortcut

Registered: Nov 14, 2005
Posts: 1453

Re: [rtwilli4] Cam on limestone [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (1 rating)  
Can't Post

rtwilli4 wrote:
I'm no scientist but it would seem that more surface area would mean just that... more friction. Am I wrong?
No. Simple friction theory suggests that surface area is irrelevant. Simple friction is very accurate for hard cohesive surfaces. And in the case of rock on metal it holds very true.

It can get more complicated in other cases though. Ice skates use low surface area for lower friction. Whereas skis use large surface area for lower friction.


rtwilli4


Jan 11, 2011, 8:20 PM
Post #16 of 34 (16062 views)
Shortcut

Registered: Feb 14, 2008
Posts: 1867

Re: [patto] Cam on limestone [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (0 ratings)  
Can't Post

I've had just a bit too much Beam to be thinking about all that :)


uni_jim


Jan 11, 2011, 8:56 PM
Post #17 of 34 (16045 views)
Shortcut

Registered: Mar 27, 2008
Posts: 429

Re: [Hexciter] Cam on limestone [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (1 rating)  
Can't Post

Hexciter wrote:
While surfing over net, I read comment for cam physics on limestone in forum of DCU Rock Climbing Club.

- CAMMING ANGLES -
Basically avoid Black Diamond Camalots if you
ever plan on climbing on limestone. All camming devices use the basic
logarithmic camming angle of 12.75 Degrees from normal except Black Diamond! Camalots are designed to give a larger expansion range per device, to do this they use a different camming angle that diverts the force of a fall more downwards and less outwards (towards the crack walls) (and they use 2 axels). this means that camalots will pull, Rip, pop-out much more easily on rock with lower coeficents of friction - e.g. limestone. All friends require extra care when being placed on limestone but camalots even more so and should be avoided. they work well on sandstone and granite though. And if you dont want to climb on limestone you're missing out!

Source is:
https://www.redbrick.dcu.ie/~climbing/phpBB3/viewtopic.php f=6&t=225&st=0&sk=t&sd=a&sid=c7f78c4ed5f4c431b2b9683510ccb960&start=15

He made a mistake that camming angle of Friend should be 13.75 degree as patented by Jardine, not 12.75.

What's your opinion? Does it make so much difference?


Get out of the lab.

Limestone, in my experience, almost never will give you a "perfect" parallel crack. You will have pods or edges that you can use to your advantage, turning your cam into a nut with an expansion range. Learn how to use these and the cam angle won't make a lick of difference. I have fallen on cams in limestone, and not one has pulled. You just gotta learn how to use em!


billcoe_


Jan 12, 2011, 11:39 AM
Post #18 of 34 (15967 views)
Shortcut

Registered: Jun 30, 2002
Posts: 4693

Re: [uni_jim] Cam on limestone [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (0 ratings)  
Can't Post

I'm calling bullshit that Limestone has a lower coefficient of friction than granite, or probably sandstone as well. It's true that Metolius cams have a better angle for holding and sticking, but really, where are all these BD cams ripping out of rock stories?

BTW, the Totems are pretty respectable and have a claimed better holding angle than other cams (claimed), anyone try them on Limestone?


Partner camhead


Jan 12, 2011, 11:48 AM
Post #19 of 34 (15960 views)
Shortcut

Registered: Sep 9, 2001
Posts: 20939

Re: [billcoe_] Cam on limestone [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (1 rating)  
Can't Post

billcoe_ wrote:
I'm calling bullshit that Limestone has a lower coefficient of friction than granite, or probably sandstone as well. It's true that Metolius cams have a better angle for holding and sticking, but really, where are all these BD cams ripping out of rock stories?

Granitegirl linked a story just above in this thread.

Also, Goran Kropp's death in 2002 involved pulling out at least two camalots from a parallel sided basalt crack.


granite_grrl


Jan 12, 2011, 4:34 PM
Post #20 of 34 (15901 views)
Shortcut

Registered: Oct 25, 2002
Posts: 15084

Re: [camhead] Cam on limestone [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (0 ratings)  
Can't Post

camhead wrote:
billcoe_ wrote:
I'm calling bullshit that Limestone has a lower coefficient of friction than granite, or probably sandstone as well. It's true that Metolius cams have a better angle for holding and sticking, but really, where are all these BD cams ripping out of rock stories?

Granitegirl linked a story just above in this thread.

Also, Goran Kropp's death in 2002 involved pulling out at least two camalots from a parallel sided basalt crack.
Whoo! That's me!

Chossmonkey still has the scars on his ass from that experience.


rtwilli4


Jan 12, 2011, 5:21 PM
Post #21 of 34 (15877 views)
Shortcut

Registered: Feb 14, 2008
Posts: 1867

Re: [uni_jim] Cam on limestone [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (0 ratings)  
Can't Post

uni_jim wrote:
Limestone, in my experience, almost never will give you a "perfect" parallel crack. You will have pods or edges that you can use to your advantage, turning your cam into a nut with an expansion range. Learn how to use these and the cam angle won't make a lick of difference. I have fallen on cams in limestone, and not one has pulled. You just gotta learn how to use em!

But in that case wouldn't you just use hexes? Wink

In my experience cams are OK but tricams nuts and hexes are better. But I've only climbed on limestone in Asia.


bearbreeder


Jan 12, 2011, 8:55 PM
Post #22 of 34 (15814 views)
Shortcut

Registered: Feb 1, 2009
Posts: 1960

Re: [Hexciter] Cam on limestone [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (0 ratings)  
Can't Post

if there's a good stance i like to place a nut or tricam wherever i can ... allows me to save the cams for the harder parts ... less likely to pull IMO as well

a set of 0.25-2 tricams sit on a single biner on my harness all the time


Hexciter


Jan 13, 2011, 2:15 AM
Post #23 of 34 (15756 views)
Shortcut

Registered: Jan 9, 2010
Posts: 7

Re: [rtwilli4] Cam on limestone [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (0 ratings)  
Can't Post

I have been just considering Totemcams has a better value in the limestone. The parallel cracks is good for regular cams are rare. The limestone gear have very different priorities that used in the granite. No cam abuse. The best is balanced mix of what is available, in my opinion.


billcoe_


Jan 13, 2011, 6:58 AM
Post #24 of 34 (15706 views)
Shortcut

Registered: Jun 30, 2002
Posts: 4693

Re: [camhead] Cam on limestone [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (0 ratings)  
Can't Post

camhead wrote:
Granitegirl linked a story just above in this thread.

Thanks Camhead! I need to click links:-) Scary stuff. Does anyone know if the cams track out, like in softer sandstone, or if it's that the rock really has less friction coeffecient?

BTW, do NOT run out and get the dmm cams. Damn near identical to the BDs on the business end and cam angle with one tragic exception that might kill ya in softer rock: the cam lobes are ever skinnier! I suppose that they did that to shave a fraction of an oz off, but they could have hot forge stamped it so that the business part of the lobe was flared, and larger. Except that would have cost more. I have great respect for DMM, but feel they kicked this out the door before it was prime time.


kennoyce


Jan 13, 2011, 9:25 AM
Post #25 of 34 (15664 views)
Shortcut

Registered: Mar 6, 2001
Posts: 1338

Re: [billcoe_] Cam on limestone [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (1 rating)  
Can't Post

billcoe_ wrote:
camhead wrote:
Granitegirl linked a story just above in this thread.

Thanks Camhead! I need to click links:-) Scary stuff. Does anyone know if the cams track out, like in softer sandstone, or if it's that the rock really has less friction coeffecient?

BTW, do NOT run out and get the dmm cams. Damn near identical to the BDs on the business end and cam angle with one tragic exception that might kill ya in softer rock: the cam lobes are ever skinnier! I suppose that they did that to shave a fraction of an oz off, but they could have hot forge stamped it so that the business part of the lobe was flared, and larger. Except that would have cost more. I have great respect for DMM, but feel they kicked this out the door before it was prime time.

Cams don't track out of limestone like they do in soft sandstone, generally when they pull it is because the rock has a much lower coefficient of friction. Limestone is mostly calcium carbonate which is very slick. I don't know if you've climbed much sandstone in the desert, but if you have, the slick white buildup in some places on the rock is calcite which is also calcium carbonate. Limestone can be that slick especially if it gets polished.

Cams can hold in limestone, but unless they are in a pod, I wouldn't count on them.

First page Previous page 1 2 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