perfect retraction for cam lobes

when i was taught to how to place a cam i was told that the perfect amount of retraction is where the straight part of the lobes line up so that the lobes don't overlap but there is not a gap between them when looking from a profile view. recently i was told, though, that this is overcammed. i am still very new to SLCDs so i figured i should ask. thanks

yeah, that's overcamming. It's not really that it won't hold a fall, it's more you might get the gear stuck so you won't be able to retrieve it. Usually about 40%-90% closed is considered the sweet spot.

There is no "perfect" when it comes to retraction.

If it's too compressed, it may be difficult to remove (but still will do its job). If it's too little compressed, any slight shifting or crumbling of the rock surface may cause the piece to open up (and fail...UNSAFE).

Also, the smaller the piece, the more you need to worry about undercompressed, as little pieces have significantly less range than bigger cams. Corollary - don't let beginners place 0 or 00 size cams.

If you looked from the side, I consider a proper cam to be somewhere between where the back of the lobes make a 90, to where they begin to touch (where you said), knowing that one end of that range is under cammed and one is nearly over cammed. Error away from the side you are worried about.
With that being said, most can retract beyond where they start to overlap, so your placement will still be able to be removed from what you said, and I'd rather have a cam hold and stuck forever then pop out because it was undercammed

Not enough retraction -> cam could pull if you fall, either because of flex in cam and/or rock, or because cam walked a bit, or because small local contact (crystal) got crushed or deformed metal of lobe

Too much retraction -> your cam could become fixed, especially if it walks at all

Conclusion: when in doubt, err on the side of overcamming....

If the cam is easily cleaned, it's NOT over-cammed, even if it looks like it.

DrApnea wrote:If you looked from the side, I consider a proper cam to be somewhere between where the back of the lobes make a 90, to where they begin to touch (where you said), knowing that one end of that range is under cammed and one is nearly over cammed. Error away from the side you are worried about. With that being said, most can retract beyond where they start to overlap, so your placement will still be able to be removed from what you said, and I'd rather have a cam hold and stuck forever then pop out because it was undercammed

Exactly...at least according to the Wild Country cam book and they know.

And if you are ever worried that your cam is overcammed or undercammed but feel like you don't have a better option, at least sling it long. I see so many people clip their cams short and then end up with all of the stems sticking straight out of the rock face or their gear stuck.

Perfect for what?

The holding power of the cam is the same regardless of how much compression there is of the cam lobes, as long as the cam isn't tipped out. So there is no holding power reason to prefer one level of cam compression to another. What matters, then, is security, and security means that the cam isn't going to move into a position in which it will no longer hold.

The most secure cam is one that can't move because the lobes are fully compressed. Unfortunately, such cams can't be removed and so are not a practical solution to the security issue. Properly speaking, this is the only placement that can be said to be overcammed. If the lobes can be retracted with the trigger mechanism, the cam isn't overcammed.

So, the "perfect" placement is one with enough compression that no cam motion can come close to springing free any of the lobes. This depends on how irregular the crack is in the locale of the placement, compared to how much range the cam has. The smaller the cam, the more lobe compression is desirable because the range will also be smaller and so motion tolerance will be less. To this one wants to add a cushion in case a bit of rock crumbles and/or one misjudges what might happen if the cam moves a little. If two sizes will fit, the larger size (with the tighter fit) is usually a better bet, as long as the larger fit isn't so tight that small motions will get the cam stuck. Again, the presence or lack of crack uniformity has a lot to do with the decision.

I think trying to make rules based on the shape of the cam is a bad idea; different manufacturers shape the non-contact parts of their cams differently, and some cams are mounted on a single axle while others are on double axles. You really should be attending to how the cam surfaces touch the rock and what crack irregularities might do to the placement, rather than looking at cosmetic features of the lobe geometry.

If I understand correctly, that seems ok to me. I was told anywhere from 0 to 45 degrees when I was learning how to climb. Here is a good post on cams from a blog that I follow... hopefully it helps!

seekingexposure.com/climbin…

As a general guideline (and in spite of my comments about not trying to decide by cam features that may vary from manufacturer to manufacturer), I'd go with the author's suggestion of a 45 degree cam lobe angle as approximately the most open the cams should be . But I think it is much easier to eyeball the angle between a pair of cam bottoms rather than the angle between a single cam and the stem (especially in horizontal placements, where the stem will not bisect the cam-bottom angle), so I'd convert the author's guideline to a 90 degree angle between cam bottoms.

Still, this depends to some extent on the size of the unit itself: for very small cams 90 degrees is already getting to be too big, whereas big cams will tolerate more without risking too much instability.

I really don't understand the generic concept of "overcamming" advanced by the author and others (with no explanations, I might add). It certainly has nothing to do with either holding power or stability. If the lobes can be retracted and the cam removed without a struggle, it isn't overcammed in my book. Perhaps the issue is that tightly compressed lobes can get overcammed with small amounts of walking if the crack tapers? Something to think about but not always an issue.

Getting the stems oriented in the direction of the load is important. Cams placed in pods in vertical cracks and sticking straight out are unpredictable if the pod prevents the cam stem from aligning in the direction of the load.

The instructions for the C4 warns against "overcamming" with no further explanation. Never have really understood why they show this, except maybe to prevent you from getting your cams stuck.

demandware.edgesuite.net/aa…

thanks guys this really helped. i usually place my cams with the lobes about 0 degrees but it's good to know that, if it may be difficult to extract due to the topograhpy, i can safely go to around 30 degrees (the idea of 45 or even 40 degrees scares me)

I show folks the pac-man method

- pacman with its mouth in the "normal" position ready to gnom gnom gnom some ghost is good

- pacman with its mouth just closed is ok

- pacman with its mouth a bit more open is ok ... Unless its a small pacman

- pacman with its mouth over bitting itself will work but ull probably owe me a cam when it gets stuck

- pac man with its mouth wide open is bad

- both side of pacmans mouth should be pretty similar

- face pacman so his ass is in the direction of the pull

Gnom gnom gnom !!!

;)

bearbreeder wrote:I show folks the pac-man method - pacman with its mouth in the "normal" position ready to gnom gnom gnom some ghost is good - pacman with its mouth just closed is ok - pacman with its mouth a bit more open is ok ... Unless its a small pacman - pacman with its mouth over bitting itself will work but ull probably owe me a cam when it gets stuck - pac man with its mouth wide open is bad - both side of pacmans mouth should be pretty similar - face pacman so his ass is in the direction of the pull Gnom gnom gnom !!! ;)

I actually really like that explanation - lol. Makes perfect sense...

rgold wrote:As a general guideline (and in spite of my comments about not trying to decide by cam features that may vary from manufacturer to manufacturer), I'd go with the author's suggestion of a 45 degree cam lobe angle as approximately the most open the cams should be . But I think it is much easier to eyeball the angle between a pair of cam bottoms rather than the angle between a single cam and the stem (especially in horizontal placements, where the stem will not bisect the cam-bottom angle), so I'd convert the author's guideline to a 90 degree angle between cam bottoms. Still, this depends to some extent on the size of the unit itself: for very small cams 90 degrees is already getting to be too big, whereas big cams will tolerate more without risking too much instability. I really don't understand the generic concept of "overcamming" advanced by the author and others (with no explanations, I might add). It certainly has nothing to do with either holding power or stability. If the lobes can be retracted and the cam removed without a struggle, it isn't overcammed in my book. Perhaps the issue is that tightly compressed lobes can get overcammed with small amounts of walking if the crack tapers? Something to think about but not always an issue. Getting the stems oriented in the direction of the load is important. Cams placed in pods in vertical cracks and sticking straight out are unpredictable if the pod prevents the cam stem from aligning in the direction of the load.

Do not quote me on this, but from my understanding I do not think overcamming is really as much of a strength issue as it is an am-i-going-to-get-my-cam-back issue.

The problem with overcamming is any walk at all and you might as well have just pounded in a piton. I have lost like 5 blue master cams by overcamming them and then never being able to get them out.

Again, that has always been my understanding, but I am not an authority on the topic. It would actually be interesting to reach out to BD or Metol. and ask...

While we're on this topic, does anyone else think they should be placing a #3 here

cam retraction

Conor Mark wrote:While we're on this topic, does anyone else think they should be placing a #3 here

That looks OK to me.

Mike wrote: That looks OK to me.

Would be pretty funny if the BD boys had a bad placement in their website shot for cams - lol. Placement looks good to me, but if I had to choose, gun to my head... it leans more twd the undercammed spectrum in my opinion. Depending on if there is any flair in that crack a good case could be made for a number 3 for sure.

Jake Jones wrote:Larger cams (by my own definition are #1 and up) are much more forgiving. I won't think twice about putting in a #3 with the tips of the lobes intersecting each other (from a profile view), but try to stay away from it with smaller cams.

Interesting experience Jake, I've personally found the opposite to be true. I've only lost 2 cams due to overcamming, a BD 3 and 5. Both probably could have been removed, but were on big climbs in Zion where it was more important to keep moving. With small cams (BD 0.4 and smaller), I will usually retract them fully and try to slot them like a nut. Usually removal is no big deal, if the follower removes them the same way they went in.

CCase wrote:Again, that has always been my understanding, but I am not an authority on the topic.

Rich is an authority on the topic, and you would do well to listen to him.

Conor Mark wrote:While we're on this topic, does anyone else think they should be placing a #3 here

I've climbed that size crack. That's the right size. A #4 might barely fit in there. In fact, I have used a very tight #4 and a loose #3 in conjunction with each other to get through that size.

The rule of thumb I use is: take the full trigger pull, then divide that pull into thirds. Placing at about 2/3 is generally "good."

But as previous posters have suggested, ANY retraction in a perfectly ideal crack has the same holding power; walking and overcamming/getting stuck are the problems.