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tradmania
Jun 21, 2009, 1:01 PM
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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.
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billcoe_
Jun 21, 2009, 1:46 PM
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no - personal preferance.
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clc
Jun 21, 2009, 2:38 PM
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You'll pull the trigger differently.DMM's are cheap and lighter. BD are better quality. Go with Metolious if your getting that style.
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shoo
Jun 21, 2009, 2:53 PM
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billcoe_ wrote: 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.
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rocknice2
Jun 21, 2009, 3:14 PM
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shoo wrote: billcoe_ wrote: 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
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shoo
Jun 21, 2009, 3:49 PM
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rocknice2 wrote: shoo wrote: billcoe_ wrote: 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
The stem runs over an edge in this highly specific to the point of uselessness scenario, causing the force to be straight out.
And in any case, without the ledge, the torque on the singles stem is less than the u-stem.
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vegastradguy
Jun 21, 2009, 6:23 PM
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wow- bd vs. dmm?
have you handled both? which do you prefer? i would recommend looking at metolius for u-stem cams if you havent already. (edit- i see you're in england, is metolius even available? i seem to remember that they didnt carry uiaa cert for a long while, but maybe they do now....)
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.
in terms of u-stem vs single stem- in the bigger than fingers sizes, i would say that the differences are minimal most of the time.
in the smaller stuff, though, the wider head of a u-stem starts to become liability.
(This post was edited by vegastradguy on Jun 21, 2009, 6:24 PM)
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tradmania
Jun 21, 2009, 7:24 PM
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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.
(This post was edited by tradmania on Jun 21, 2009, 7:27 PM)
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swaghole
Jun 21, 2009, 7:41 PM
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tradmania wrote: 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.
I find that single-stem cams like the Camalot are more flexible than u-stem cams. This can make them easier to place in some cases. Also, the lenght of the stem on the Camalot is longer then on the DMM. IMO, the longer stem makes it easier to place and to retrieve it.
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oldsalt
Jun 21, 2009, 9:15 PM
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I'm still trying to decide. I put a Trango Flexcam in a deep sandstone pocket and moved on. A few minutes later, as I cleaned on descent, that #7 flex had crawled back into a larger space in the back.
I spent nearly 45 minutes playing with that thing before giving up. I think that the Metolius U shape that I replaced it with would have been easier to work out.
I also think that the outer cams can be worked separately with the two wires. I'm adding more of these.
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patto
Jun 21, 2009, 11:06 PM
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I like DMM products and I have a couple of 4CUs on my rack. However singles stems are entirely superior to a U stem design.
I haven't heard one functional advantage of U stem over single. (though U stems are often fractionally lighter) The big disadvantage of U stems are when cams are placed in a diagonal crack or if they are placed horizontally stemmed in a vertical crack. Both these placements put large torques on the cam with a U stem.
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gunkiemike
Jun 22, 2009, 2:30 AM
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In my experience, U stem cams are somewhat easier for novice climbers to remove.
HB cams are very good examples of the U stem design. If you've used them, you have a good idea of what the U stem offers.
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granite_grrl
Jun 22, 2009, 12:13 PM
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Honestly, I think it does come down to personal preference and knowing how to place your cams.
I recently got a small Metolious Master cam to double up on this size in my Metolious TCU. On a recent trip to the Gunks I found many placements where the Master cam worked better than the TCU, but I found an equal number of placements where the TCU worked better than the Master cam (I loves my TCUs).
So in summery: they're both good (single stem and double stem). Best thing to do is climb on other people's racks and decide what you like best.
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omenbringer
Jun 22, 2009, 1:31 PM
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vegastradguy wrote: 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.
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welle
Jun 22, 2009, 2:31 PM
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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.
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Storjon
Jun 22, 2009, 2:56 PM
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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.
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verticon
Jun 22, 2009, 3:06 PM
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I own a set of C4s (from #.3 to #3) and a set of DMM 4CU (#0 to #3.5) and they complement each other very well (sizewise), but I rarely take both sets on the same ride.
The C4s are my favorites for granite, while I'd rather use the 4CU's on limestone, because, due to the 13.75 deg. angle, 4CUs tolerate a smaller coefficient of friction with the rock then the C4s.
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acorneau
Jun 22, 2009, 3:08 PM
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Another Metolius cam user here, TCU's #1-4, FCU's #5-10. In addition to what others have said, I like being able to pull the cam trigger with 1, 2 or even 3 fingers if I wish.
Also, I've never had a problem of having to place them in a vertical crack but over a horizontal ledge (Shoo's scenario in post #4). If that's the best/only placement then I'll pick a more appropriate device (like a Tricam, perhaps) or simply move the cam up the crack a little to clear the ledge.
(This post was edited by acorneau on Jun 22, 2009, 3:10 PM)
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omenbringer
Jun 22, 2009, 3:42 PM
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welle wrote: 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
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shoo
Jun 22, 2009, 3:57 PM
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omenbringer wrote: 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
How is that a benefit of u-stems? You can do the same thing with single stems.
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cracklover
Jun 22, 2009, 5:08 PM
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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
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shimanilami
Jun 22, 2009, 5:24 PM
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If the placement is big and/or straightforward, then there is little difference in performance. If the placement is slanted and small (i.e. "tweaky"), then single stem designs are preferred, as they are less likely to torque the head out of its ideal placement. (So if you're free climbing at Indian Creek, both will work fine. If you're aid climbing in Yosemite, you'll want a single stem design.)
Another consideration is that (IMO) single stem models are easier to handle for people with big hands. I, at least, have a difficult time getting my fingers into Metolius u-stem cams. I find them harder to place and to remove. (The C3's are an exception, however, because their finger action is more similar to single stem models'.)
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cracklover
Jun 22, 2009, 5:34 PM
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Storjon wrote: 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.
For a single stem solution, Aliens are quite good in this respect. And depending on how shallow the placement is, a forged friend with a Gunks tie-off can be the absolute best solution.
GO
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omenbringer
Jun 22, 2009, 5:40 PM
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shoo wrote: omenbringer wrote: 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 How is that a benefit of u-stems? You can do the same thing with single stems.
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patto
Jun 22, 2009, 11:08 PM
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Storjon wrote: The Dmm wire attachments can swivel on the axle and this reduces the aforementioned torque in verticals.
This reduces torque about the axle. Not torque about the placement.
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