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 Post subject: Cam angle and range
PostPosted: Wed Aug 04, 2010 2:16 pm 
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Joined: Mon Nov 19, 2007 3:13 pm
Posts: 694
After looking at the picture and info for the new Helium Friend and thinking it looks impressive and promising, I gave it a little thought and now I'm a bit troubled. How did they manage to get "up to 20% more range" and keep the "original 13.75 degree angle" with the "original single axle"? Can anyone please explain this to a simpleton? I can totally get it that by making the lobes more elongated you can get more range, but then you loose the constant cam angle, don't you? As I understand it, the idea behind the twin axle design is to make it possible to have that more elongated lobe and still maintain the constant cam angle. I haven't thought this through, but I expect you can make the lobes more elongated the further apart the axles are. It gets a little complicated, but none of this matters really as they haven't used 2 axles, it still is only one. How does it work then?

I tried to google it, but I came up with lots of car stuff and dodgy pictures when I searched for "cam angle" pictures. I even got back a picture of KISS on stage :roll:

Anyway, I found this explanation by John Middendorf: http://www.bigwalls.net/climb/camf/index.html
Interesting and confirms what I thought, but it doesn't help me to think of a way Wild Country increased their range. Maybe they found a way to make the lobes "longer", which come to think of it, shouldn't really be all that impossible. But it doesn't look like it, it kind of looks like it's the other way round :?

Image

and here's picture of the current tech friend:
Image


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 Post subject: Re: Cam angle and range
PostPosted: Wed Aug 04, 2010 2:56 pm 
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Joined: Fri Dec 15, 2006 12:32 pm
Posts: 1168
Location: Cape Town
Real Name: Willem Boshoff
mmm, ja, the answer to your question is a mystery to me. what's not a mystery however is that you'll be willing to give one of your nuts to get your hands on a set of these :mrgreen:

some rep from wild country posted this on climbing.com:
"The cam angle remains at the definitive 13.75 degree constant cam angle that Wild Country pioneered which we feel gives the optimum blend of range and holding power. However, i am not going to say how we have increased the range as is stated on the picture Mick has posted - this will be revealed later on - but save to say part of this was to slightly alter the size of each Friend. Importantly this also means there are less sizes (9 not 11) which cover better the same range as before - and overlap better too... "

and don't pretend that you did not like the picture of KISS - we all know what kind of music you listen to


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 Post subject: Re: Cam angle and range
PostPosted: Wed Aug 04, 2010 4:15 pm 
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Joined: Wed Nov 05, 2008 5:14 pm
Posts: 213
Location: Cape Town
Real Name: Ernesto Ismail
You have half the answer.

You do increase range by making the cams "longer". This does not however imply that you must change the shape of the cam. All you need to do is add more of the same curve onto the end of it.

I suspect that if you took one of the old cams and one of the new ones and placed them on top of each other they would be coincident for the length of the shorter cam.

Theoretically you can add on an infinite amount of cam range. What prevents this is that unless you have a linear cam (not really a cam then) at some stage the cam doubles back on itself, at which stage you lose the beginning of the range. All cams in the same series (same camming angle), fall on the same curve. Additionally, there is the issue of the back of the cam interfering with the opposing cam. This restriction is generally what limits cam size.

I suspect that the backs of each cam are now closer to the face of the other when at minimum range when compared to the old cams.

This explanation might have been easier with a diagram, but I'm too lazy to walk upstairs to the scanner.

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I don't think, therefore I'm Not


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 Post subject: Re: Cam angle and range
PostPosted: Thu Aug 05, 2010 9:23 am 
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Joined: Mon Nov 19, 2007 3:13 pm
Posts: 694
Thanks Not! I think we're thinking the same thing, so no need for the picture, I'd be too lazy too. I hobbled down to the gear room last night to pay my friends a visit and see how they're doing. There's not that much room for improvement I think. If you pull them further their tips will go all the way round and basically overtake the opposite lobe's small end (the bit that needs to cam when trying to make the smallest placement). Basically the ends will push into the opposite side of the crack, preventing the small part of the cam to touch the rock. So, I don't see how they can make it longer, unless it means you have to make a shallow placement to allow the ends to stick out of the crack, but that's just a little undesirable.

In my experience, cams don't have as much practical range as theoretical range in any case. Pushing the limits on the smaller range just results in loosing cams and I've never felt comfortable on the outer limits - they just don't feel stable enough for my liking when they hang by their "finger tips". They tend to walk more that way in any case.

Hey Mock, it depends on which nut :cyclops: What do you, or rather the guy you quoted, mean by 11? There are 14 that I'm aware of. I have all from 00 - 4 except 1.25 and 1.75 and then there's the vulture clobber and the battle axe.
No ways, I don't want to say they are too gay, because I'm not keen on getting clobbered by a platform shoe, so lets just say "I was made for loving you baby" is just not me :puker:


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 Post subject: Re: Cam angle and range
PostPosted: Thu Aug 05, 2010 9:35 am 
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Joined: Fri Dec 15, 2006 12:32 pm
Posts: 1168
Location: Cape Town
Real Name: Willem Boshoff
dunno about the number of cams - just copied and pasted....
janee, they do not really stack up to iron maiden or led zep :thumright


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