UKH

Has anyone seen the  alarming sliding with a slight side loading in this video?  The crack in this case is pretty smooth.

Do you know if this also occurs with more conventional cams?  I guess I should test it but I thought I would ask.

https://www.totemmt.com/2017/01/totem-cams-in-horizontal-placements/

In reply to paul wood:

What awful backing music! That would be much more watchable if you could actually hear what Mikel is saying.

In reply to Jenny C:

If you scroll down, there's a transcript.

In reply to paul wood:

Is it alarming? Just looks like the cam 'walking' in the crack when you wiggle it, which is a pretty well known thing.

In reply to paul wood:

It happens with all cams. It's a bit exaggerated here because of the amount he wiggles it, the smooth surface and the cam being on the verge of under-cammed.

In reply to paul wood/Jimbo:

What's the actual issue with being undercammed? Surely the cam has equal fall holding strengh at all extensions (from the shape/curve of the cam) so the issue is that the spring is more relaxed/less force when more open, and less force is applied to hold it in place?

In reply to ebdon:

I was really surprised by the extent of its movement with just one (albeit large) pull to the left.  This would see many cams falling out especially on limestone.  My experience of cams walking usually involves them going further in (and possibly opening) rather than out.  I have not used any Totems and I wondered if this was a feature of their unique design.  I am left thinking that the friction usually prevents this.

In reply to paul wood:

Thanks for pointing this out though.  I had always wondered if it was better to stuff the cam into the horizontal crack or to put at an angle in line with the load.  Now I know!

In reply to wbo2:

This should be true for normal cams, but for totems there might actually be a difference. This is because the lobes don't follow the standard logarithmic spiral shape seen in other cam designs. However I'm not sure how the maths actually works.

In reply to Connor Nunns:

I have A levels in maths , further maths and physics, and a degree in civil engineering and  can just about handle the maths for an slcd in a straight pull in a parallel crack. If the pull is to one side, it gets complicated, even more so with double axles or totems. 

In reply to paul wood: I thought there were subtle differences between brands, but this would surely only come into play when a large force was applied. I guess you'd compromise fall resistance for a greater range by tweaking the shape, but is that the case here? Seems unlikely to me, otherwise they'd never hold anything

In reply to paul wood:

Outer lobes on bottom if placing in horizontal crack. Not sure I’ve ever consciously thought about that.

In reply to Brass Nipples:

It won't make a whole lot of difference. Certainly not to holding power. The only difference is that, because the top cams will have less force through them when not loaded (i.e. the force of the cam spring minus the weight of the cam itself), these are the ones than are more susceptible to 'walking' (which is actually just the cam lobes sliding across the rock rather than gripping). And if they the cams at the top are closer together then for the same angle of rotation any walking will be less pronounced than if they are further apart.

In reply to wbo2:

Yes, those things are right and also I think that a cam is more forgiving of walking a little when it's more closed. If undercammed it might fall out if it walks and opens a bit whereas a bigger cam would just open a bit and stay in.