no - personal preferance.

This is not true.

1) U-stems tend to have wider heads, since they have to have crap on the ends for the wire to attach to. Won't matter in the least in a splitter crack, but it might in other placements.

2) There are some placements (usually marginal ones) where a fall will produce strange torque on the lobes of the cams. Think about placing a u-stem cam vertically, straight out, with a ledge underneath it. A fall will cause the top lobes to pull out and down, while pushing the bottom lobes in and up. This could cause it to rotate enough to fail. With a single stem, the force is still straight out.
Overall, I believe that single stems are a objectively superior design. I am hard pressed to think of scenarios in which it would be better to have a u-stem.

What??? Even a single stem suffers from torque in your scenario

Thanks for the advice guys. I'm not interested in a DMM vs BD debate - god knows this has been done to death. I am specifically curious as to any functional difference or advantage/disadvantage of single stems and U stems.

Edit: in terms of what I have used, so far I have placed HB quadcams, BD camalots, metolious cams, DMM 4TCUs and WC Friends, and I own a mixture of HB quadcams and camalots.

Thanks.

wow- bd vs. dmm?
personally, dmm would probably be the last u-stem cam i would buy (no offense to dmm, everything else they make is tops in its category)- the action is horrible on them, imho.

I climbed with someone who had DMMs couple of weeks ago, and they were pain in a butt to clean. the triggers are outside of very wide U stems and a lot of times were hard to put fingers on both especially when placed far back in the cracks. I used my nut tool a lot to get to the trigger, but of course with the nut tool only one side would engage and it would cause the cam to walk - was pretty frustrating to clean. If the price is concern, you'll probably save $$$ by buying more expensive camalots, if you don't want to lose your cams.

Another benefit to U-stems that hasn't been mentioned is the ability to get them double slung (DMM's come that way). Though not always possible it can eliminate the need for a quickdraw or runner

One thing people often overlook in camdesigns is the stem termination/axle attachment.

Singlestem designs often require a longer and larger stiff attachment due to larger wire rope dimension and this stiff bit will hamper stem flex in shallow horrizontal placements in smaller sizes.

Other than the WC Zeros, all single stem have this problem in varying degree when simmilar size U-stem designs dont have this problem( compare a #1 WC tech friend with #1 DMM).

The Dmm wire attachments can swivel on the axle and this reduces the aforementioned torque in verticals.

How is that a benefit of u-stems? You can do the same thing with single stems.

The Dmm wire attachments can swivel on the axle and this reduces the aforementioned torque in verticals.

Another Metolius cam user here, TCU's #1-4, FCU's #5-10.

what the hell does a metolius 9 and 10 look like? I've never seen either of those.

For bottoming vertical cracks, U-stem cams (especially quad cams, but also tcus) absolutely suck, while single stem cams often provide adequate protection.

Also, U-stem cams are more prone to walking, since the cable doesn't flex with movement.

GO

-I also think that in some cracks that are irregular, a 3 lobe profile is much, much easier to fit than 4 lobes, regardless of the actual width of the axle.

I do disagree that u-stems walk more. I tend to sling most of my stuff aside from desert splitter climbing. Perhaps you are talking about U-stems walking more when clipped straight in? I could see that being true, though I haven't experienced it.

For small sizes, though, Three Cam Units are the bomb, and this is something that a single stem cam can't have... single stem units are all 4 lobed.
-TCUs tend to pivot instead of walking like 4 cam units do, and I have seen way less stuck 3 cam units vs 4 cam units as a result.
-I also think that in some cracks that are irregular, a 3 lobe profile is much, much easier to fit than 4 lobes, regardless of the actual width of the axle.

I generally find that my u-stem cams (DMM) walk less than my single stem cams. The flex in the cable of a single stem cam really isn't enough to eliminate walking (with the exception of aliens), but the way the sling is just looped around the cable instead of sewn tightly like with a C4 seems to allow more movement of the rope with less walking.

I agree with your whole post.


I generally find that my u-stem cams (DMM) walk less than my single stem cams. The flex in the cable of a single stem cam really isn't enough to eliminate walking (with the exception of aliens), but the way the sling is just looped around the cable instead of sewn tightly like with a C4 seems to allow more movement of the rope with less walking.

This has nothing to do with inherent differences between U-stems and single stems, and has everything to do with sling styles.

This is true, but since the OP is asking about DMM vs. BD, and I am comparing DMM slings to BD slings, it is completely relevant.

Hi all,

I'm looking at replacing some cams, and have narrowed it down to DMM 4CUs and BD Camalots. I am curious if there is any functional difference or disadvantage/advantage of single stems (such as WC or BD) as compared to U stems (HB quadcams, DMM etc).

Thanks.