BD .5 Axle Slips?

A friend pulled a BD C4 (my .5). This shit happens I know that, he was OK and we called it a day. The interesting part is that when I lowered him to the ground and unclipped the cam from the rope I immediately noticed that 2 lobes were not open all the way. When I looked closer I saw that the axle had slid through the head of the cam and was sticking out of the side of the cam opposite of the stuck lobes. The axle had shifted a sufficient amount to cause enough friction that the 2 lobes could not uncam themselves.

This was a vertical placement under an overlap. The tail of the cam was was pointed straight down. The cam was not behind a flake and the rock did not blow out (for all you internet analyzers).

When I got home I tried to recreate the lateral axle movement @ home on other C4's of various sizes and had success, but not to the point where the lobes would stick. Granted I wasn't hammering the shit outa my gear (I'd still like to use/trust it). So the question is:

Are the axles supposed to move laterally through the head of the cam? And if so, to the point where it creates enough friction on one side of the unit to prevent 2 lobes from applying outward force?

Not a big surprise since they are now made in China. Probably a lack of interference fit in the head of the stem. I am so happy I got all mine pre outsourcing.

BD's cams have slightly long axles to allow for a healthy amount of play in the lobes. My uneducated guess is the cam got loaded, the lobes adjusted as best they could to the orientation of the fall / torque and hence moved down on the axle. This probably caused some deformation of the lobes/axle causing the lobes to stick, possibly further exacerbated by some unequal lobe engagement during the fall before pulling. Piece is clearly well loved and looks to have a few gouges possibly from the fall suggesting maybe it caught a crystal or something and the related results of such an action. all that being said Must have been a big fall - never seen or heard of the axles moving through the head.

Ryan,
Strange that you would ask this, I very recently had this exact same thing happen to me. My cam was a hand-sized DMM Dragon, but the symptoms are the same and the design of the Dragons and C4s is so similar (as far as the head is concerned, anyway) that I think there's a reasonable chance the problem is the same.

In my case, what had happened was one of the lobes slid over on the axles so it was slightly off-set from where it should be. This in and of itself was not really a huge issue, but in doing so the lobe had managed to slide over a coil of the spring that sits right next to that lobe. It was the coil pushing tightly against the lobe that was keeping the lobe from moving freely was it should.

Despite how it sounds, this wasn't obvious at all and actually took a lengthy bit of examination to spot. Once it was clear what the issue was, I was able to push the coil back out from under the lobe pretty easily and the cam was back to normal. I have no reason to suspect that the lobe or spring was damaged and I still use that cam, but without knowing anything about your 0.5 C4, I'm going to stop well short of advising you to continue using yours. Good luck either way, I'm interested to hear if your problem is similar!

This is fairly normal (not common per se but it happens enough that I knew what you were talking about before the pictures).

Just a thought though, based on my exact experiences.

I think you might have the order of events wrong. I think the cam failed because shit happens. Then the forces that caused it to fail are why it's in the position it's in. If nothing is damaged, you can pop or massage it back into place and it's good as new.

Something might be bent so check though. I've seen more bent lobes on C4's from both falls and drops than all other models of cams combined. That even includes the pre C4 Camalots. I think they shaved some weight and lost a lot of torsional strength. Has nothing to do with China.

Funny thing is, I look at your cam all beat up and used and I look at the shiny cam in the other recent incident, and without meeting either of you, I tend to think that your cam was placed correctly.

Center the head and axle by pushing on the chain link. Push the lobes apart lube and reuse. Unless the axles are bent, the can is fine.

i've seen the same thing dave alie describes a few times. assuming the axle or a lobe isn't bent, you can usually get it all re-aligned. one thing that helps in this process is taking some time to really clean and lube the area - this helps move things back where they want to be.

the tough thing in your case is that it is a .5 so you don't have much elbow room to get in there and tinker with it, so it will probably take some time. good luck and keep us posted on how it goes.

Perfectly normal and they've always done that. The extra axle length is necessary because the springs get longer when compressed. Is a good idea to check that the lobes are centered on the axle.

Might want to look into some cam lube- 7 dollars I believe
metolious Makes a white lithium compound that when dry does not attract dirt or debris into the lobes worked magic on our rack. But when ever Im suspect about a piece of pro i usually retire for piece of mind :)

Good luck to you mate And my best.

Chris Hills

Paul Leverich wrote:Not a big surprise since they are now made in China. Probably a lack of interference fit in the head of the stem. I am so happy I got all mine pre outsourcing.

Aric Datesman wrote: Nothing to do with outsourcing whatsoever.

Not only that, Matt, but the axle longer than it looks like it needs to be has been around since Lowe/Jardine (who invented cams is arguable either way). Quite simply torsion springs (which all cams other than some sizes of Aliens/Fixe/Totem use) get longer when compressed. This increase in length means the axles need to be longer than it appears necessary, and if there's sufficient friction between the axle and lobe they won't self-center and might possibly jam.

Nothing to see here; clean and lube your cams regularly and it won't be an issue.

That said, if you want something to be genuinely concerned about cruise on over to ST and take a look at the Fixe Alien that seems to have exploded by way of the axle nut popping off.... :-o

supertopo.com/climbing/thre…

Side note- Mapeze (sp?) is the guy at Totem, and what he says about their version should be taken as Gospel). And I have nothing to do with any of this; only relaying what I saw on ST.

Looking at that Cam (lobes worn smooth) it might be time to start looking for a new one.

Yes, I realize the "teeth" don't matter per se - just saying that when your gear is well worn and starts to function erratically it might be time for a new one...

mattm wrote:Looking at that Cam (lobes worn smooth) it might be time to start looking for a new one. Yes, I realize the "teeth" don't matter per se - just saying that when your gear is well worn and starts to function erratically it might be time for a new one...

Ray Pinpillage wrote: Blue Fixe Aliens don't have teeth or knurling. That cam doesn't look very warn to me. However, even if it were the axle should never come apart. fixehardware.com/shop/sale-…

Thanks for all the replies boys, I appreciate it. Nicelegs,I am flattered at your assumption the cam was placed properly. Dave, the issue had nothing to do with the springs, although your story is interesting. Eric, the friction I was talking about was from the shortened axle on one side, not from the cam not being properly maintained. If you want to learn how to properly clean your cams I can show you. I clean mine a couple times a year depending on how much I climb in the desert, and how many spring storms I get caught in per year. Thanks for the alien link BTW.

Since the post I have cleaned and lubed up my well loved .5 and mic'ed the cam to make sure nothing was bent. A few aid placements revealed she is camming as normal. She has now been returned to the rest of her family on my free rack and I am happy to say she belongs there.

Here's a few more pics to show the gouges to the lobes from the fall.

they have always had (pre c4) a bit of play in where the lobes land on the axle - even more as the cam size increases (look at a #4, 5 or 6) their "natural" position is centered and therefore not noticeable, however they can and do get pushed from one side or the other for a number of reasons - a fall, crammed into a pack, etc.

that said, i've only had one case where i can recall the lobes not moving and that was when i went to place a #3 if i recall correctly. a quick smack to the outside of the crack fixed it...