BD .5 Axle Slips?
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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. |
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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. |
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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. |
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Ryan, |
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This is fairly normal (not common per se but it happens enough that I knew what you were talking about before the pictures). |
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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. |
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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. |
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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. |
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Might want to look into some cam lube- 7 dollars I believe |
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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.Nothing to do with outsourcing whatsoever. |
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Aric Datesman wrote: Nothing to do with outsourcing whatsoever.^This^ It's been what, 7 years plus since BD opened their plant there? Show me where the cams all went to sh*t. Not the case. Heck, I'm pretty sure there have been more cam recalls from other places than BD. |
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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. |
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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 |
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Looking at that Cam (lobes worn smooth) it might be time to start looking for a new one. |
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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...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-… |
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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-…I think mattm was referring to the .5 BD which is kind of well worn. The Blue Alien is not smooth. It has machined flats that act like teeth. |
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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. |
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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. |