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Chockstone Forum - Gear Lust / Lost & Found

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Author
Kong vs Black Diamond

Bardboy
2/12/2006
11:13:04 PM
I was looking at buying a set of Kong nuts from the Chockstone Shop and was wondering how they compare to other brands e.g. Blackdiamond.

I ask the question as the Kong brand are $125 compared to $160+ for a set of 10.
rightarmbad
3/12/2006
12:18:43 PM
Pretty much the same, only more colours.

foreverabumbly
3/12/2006
7:33:36 PM
Kong gear is made from softer metal, so will warp easier than Black diamond gear, eg- harder to remove when fallen on, and also easier to chip. Plus with black diamond your paying for the brand, so you will be a way cool climber with all that black diamond bling

IdratherbeclimbingM9
3/12/2006
9:05:20 PM
With BD you are also paying for a 3x sigma rating.
patto
3/12/2006
9:48:58 PM
On 3/12/2006 M9iswhereitsat wrote:
>With BD you are also paying for a 3x sigma rating.

And what are you paying for on kongs?

bardboy
5/12/2006
10:44:09 PM
Well i'm not into the Bling thing and I plan not to fall, so I guess a set of Kong Nuts will do the job.

Thanks for the advice.
Paul
6/12/2006
11:51:34 AM
cheeper = more cams per dollar, you will be able to place more pieces of gear before you run out of money.

BigMike
6/12/2006
12:09:59 PM
On 3/12/2006 patto wrote:
>On 3/12/2006 M9iswhereitsat wrote:
>>With BD you are also paying for a 3x sigma rating.
>
>And what are you paying for on kongs?

A 7x gamma rating!!!

Paulie
6/12/2006
12:28:10 PM
On 3/12/2006 foreverabumbly wrote:
>Kong gear is made from softer metal

Won't this also mean that they'll meld into the placement better in the event of a fall, similar to an RP? In my mind this is a good thing!
Sceptic
6/12/2006
1:58:39 PM
3 Sigma is a statistical analysis term. Strictly speaking it means 3 standard deviations. According to the BD website they use this to indicate their given break strength ratings are 3 standard deviations less than the average break strength they get in testing. In effect they are saying they discount their rating or use a safety factor. Is this something special? No, it is standard practice. Most reputable manufacturers do it & it's so commonplace they don't waste breath or ink talking about it. So what does 3 Sigma mean in the context comparing nuts? Probably nothing. 1/ Because nuts generally tear out rather than break. 2/ Because the difference between between a 3-Sigma discounted break strength & average break strength is pretty small & if you are operating this close to breaking strength you are in trouble or doing something wrong. 3/ Because you don't know what discount the other manufacturers have applied to their given break strengths. As Bigmike's "7 gamma" implies, who cares.

tmarsh
6/12/2006
5:53:39 PM
I don't think what you're saying is correct, Sceptic.

The bottom line with 3-sigma rating is that it means that 99.87% of the articles produced will not fail at a load under the rated load. Or to put it another way, 99.87% of the items are stronger than the rated load would imply.

The other testing method is simply the mean failure strength of the batch. What this means for the consumer is that 50% of the items will fail below the rated strength, and 50% will fail at loads above the rated strength.

As far as I know, all manufacturers who pursue a 3-sigma rating system advertise as such. The reason is that it is very expensive to test and certify to this extent. I've spoken to a guy from DMM who talked in terms of hundreds of thousands of dollars in implementing 3-sigma testing and a fairly major ongoing commitment to random batch testing. No-one's going to put in that sort of investment and not try and get some mileage out of it.

Having said that, I don't disagree that for practical purposes it's not going to make a whole lot of difference to most people in most circumstances. Arguing about 3-sigma ratings on biners for example is a little artificial, given the breaking strength is already way above what a human could survive if they were the thing causing the impact. Nuts and cams? It's not so out of expectation that someone could put a small nut close to its rated strength in a fall. Would you rather the 99.87% or 50% rating then?

But as you point out, Sceptic, this debate kinda assumes that the nut is placed perfectly. Maybe you'd be better off buying the cheaper nuts and put the spare change into learning how to place really good gear!
Sceptic
6/12/2006
11:16:42 PM
Tmarsh, respectfully, you've got it completely wrong. 1/ Your 'guy' spun you a line or you misunderstood him. 2/ Other manufacturers have only started talking about 3-Sigma because they are frustrated that it has been misrepresented or mistaken as meaing something unique or special & so they've decided to say "me-too, look I've got 3-Sigma". 3/ There is no 3-Sigma test, there is no 3-Sigma certification, it's just a shorthand way of expressing one way of setting your ratings lower than the mean test results. You work it out with a calculator. It costs nothing. The actual testing is the same irrespective of what you want to use as a safety factor - nothing, 1-Sigma, 3-Sigma, 7-Sigma, -33%, whatever. And no responsible climbing equipment manufacturer uses Mean test results for their rating. Promoting "3-Sigma" as something special is just marketing fluff.

You must be taking the piss with your comment "would you rather the 99.87% or 50% rating when you have a small nut close to its rated strength in a fall"? Either way I'm out of it.

climbau
7/12/2006
9:37:08 AM
Page 11 of the 2005 Kong catalogue advertises testing according to sigma procedure of every piece.
That's the way I read it anyway.

tmarsh
7/12/2006
3:25:15 PM
I stand corrected. The person whom I spoke to was an employee of DMM. Convincing? Yes. Impartial, not exactly. I stick to what I said before though: the variability from bad placements is going to be a bigger issue than variability from different testing methodology. Place good gear.

cheesehead
7/12/2006
4:11:47 PM
Still, TMarsh has the right on the meaning of 3-Sigma - it's the expected (or tested, whatever) sample size that pass the test, nothing to do per se with the actual failure strength.

[A side note - as an engineer, it's very rare to see failure strengths marked on a product. I'm happy to be shown up, but climbing gear is the only example I can think of. Most other things have a rated strength. eg, expected failure loading is 12kN. 'safe' operating load is decided to be say 10kN. Divide that by 'factor of saftey' (really factor of ignorance - to plan for stuff you just don't know) - usually about 2, to achieve a rated operating load of 5kN.
One good reason for adopting failure strengths is that climbers don't 'operate' gear to a particular load level. They give a failure test once in a while.]


KONG vs BD - if the shapes are the same, then it becomes a bling question, in my opinion. I don't know the Kong shape. I'm personally a fan of BD wires. When you get enough money together, get a second set of wires - like offsets. Whatever shape you get, they will fit in places your KONG/BD ones don't (and vice versa).

Another note - a friend recently noted that his old (8 years or so, I think??) wires are still fine. His new ones from the same manufacturer all started splitting strands of the cable (through wear and tear, nothing sinister). Assuming this is 100% correct - both old and new wires still pass the same test, are rated to the same failure loading - but one is more durable. That isn't mentioned on any rating test.

muki
8/12/2006
12:35:11 AM
On 7/12/2006 cheesehead wrote:
get a second set of wires - like offsets.
This is really good advice, the offsets are golden at araps & the gramps, perfect for flaring placments
that wont take a standard wire, and the smaller HB's are brass like RP's ,so they meld to grab the
imperfections and crystals inside cracks. Personally I like the stacking action you can achieve with DMM
walnuts, a large placement can be created by stacking a large wire (#9) with a smaller one in front (#2)
and back (#5), to create a #16 nut, versatile!
PS. the only time I've seen nuts fail (not counting RP's, seen loads of them scat themselves) is when
they are placed perfectly, and then REALLY hammered. bad gear just breaks out of the rock, no matter
what its smegma rating is...the bomb
One day hero
11/12/2006
6:07:16 PM
It'd be really nice if someone would also publish what their standard deviation is!
If it's only 1% then who really cares about three sigma crap. On the other hand if they're making gear with a 10% standard deviation I'd be creeped out no matter how many sigma's they have.
Duncan
11/12/2006
10:26:05 PM
On 11/12/2006 One day hero wrote:
>It'd be really nice if someone would also publish what their standard deviation
>is!
>If it's only 1% then who really cares about three sigma crap. On the other
>hand if they're making gear with a 10% standard deviation I'd be creeped
>out no matter how many sigma's they have.

http://en.wikipedia.org/wiki/Standard_deviation



There are 18 messages in this topic.

 

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