C'Dale Ecentric BB hell

[kevinwilliams]

Guys,

There are tales of woe all over the internet about adjusting/fixing these things but I can't seem to figure out how to fix mine...

The issue-
As expected the ecentric is completely jammed in the BB shell, what's unexpected is that it is jammed when recently placed and thoroughly lubed.

I freed the non drive side cam by threading a bolt into the cam threads with some washers on the exterior of the BB shell (internet solution- works GREAT). The problem is that the drive side cam is still jammed and has no threads to use with the cool extractor (it's an unthreaded hole for the shoulder of the camming bolt). Further, the now loose non-drive side doesn't actually come out enough that I have access to beat on the interior of the stuck side.

I can insert a super tiny long bolt/skewer through the threads on the loose side but it doesn't have the strength to survive the subsequent beating and I'm afraid that I'll damage the threads.

Any thoughts on how to free the stuck side? I'm considering tapping it with a larger OD thread and then extracting but that sounds extreme and I risk ripping the un-heat-treated threads right out. Once I do get it out, how do I seat it so that it doesn't jam but does stay put? (This situation arose after all of one quick ride at Wakefield).

Other info- older 1FG, ecentric is original

Thanks!

-K

[kenholmes]

post up pictures of the dilemma, I cant imagine what this really looks like enough to think out a solution.

thanks,

ken

[kevinwilliams]

You know that it's bad news when you can't work it out with a technical manual and a diagram at hand. :bangshead:

See attached for Diagram with my notes or this LINK (http://www.cannondale.com/asset/iu_files/techcenter/2003_eccentric_bb_chain_adjustment_ owners_manual_supplement_en.pdf) for the manual

Manual indicates that backing out the cam bolt will free the "Head Wedge" (Cam)- In my case the bolt just comes right out.

[smdubovsky]

If you didn't remove the circlip from the "Head wedge" just removing the bolt should have freed both of them?

FWIW, it may be a version of a "self locking taper". Once taper angles get shallow enough depending on the material, they will self lock (no longer dependant on the bolt to keep them tight). It usually only takes a small tap to get them free. Put the bolt, circlip, and washer back in, 'unscrew' the bolt until its applying outward force, and lightly tap on the BB non-drive side until it pops apart.

Next time, think about drilling a pair of small holes though the "threaded wedge" to insert a pin punch. Heck, you could still do that.

[kevinwilliams]

That makes sense (I hadn't figured that out)- unfortunately the circlip is weaker than the force applied by the bolt when backing as evidenced by it falling out naturally when I backed the bolt out originally.

I like the tapping idea- I haven't tried it with pressure from the bolt, that might be just the ticket but it doesn't solve the problem of the circlip's ability to hold the thing togther.

I was going to thread the "Head Wedge" and extract it using say a 8mm bolt plus washers... the saga will continue tonight...

Thanks!

[wrench177]

I've only worked on one C'Dale EBB and that circlip on the head-wedge is quite weak and really needs to be replaced with a stronger one. Sounds like your circlip fell (got pushed) out.

The basic design of that EBB is once you have loosened the threaded wedge side, it makes contact with the internal pins, thereby locking the threaded side from any more movement, now the bolt starts to extract on the unthreaded "head-wedge" side, makes contact with the circlip and then as you continue to turn, the bolt head pushes against the circlip and self extracts the head-wedge.

Problem is the circlip generally gets pushed out instead the wedge. This sounds like the problem you are having. If so, I suggest going to an auto parts place and getting another circlip, hopefully a stronger one. Lowes and Home Depot may have one in the "specialty fasteners" section, but, that's a long shot. Once replaced, go slowly once the bolt makes contact on the circlip.

If you can't find a circlip and just want the EBB out quickly, loosen the bolt and free up the threaded wedge side. Now, remove both of the EBB centering screws/bolts. Using a wooden dowel or a block of wood and a hammer, gentle tap on the EBB body. Work from both sides, this should loosen the wedge enough to free up the assembly.

Ultimately, you will want to replace that circlip, otherwise trail side adjustments will be a nightmare. Just remember to use plenty of grease or anti-seize compound in the BB and always remove the bolt slowly once it makes contact with the circlip.

Let us know how things go for you.

[kevinwilliams]

I've only worked on one C'Dale EBB and that circlip on the head-wedge is quite weak and really needs to be replaced with a stronger one. Sounds like your circlip fell (got pushed) out.
.

Yup- that's pretty close, the circlip is warped- I also discovered that the washer behind the circlip is missing and the notch for the clip is pretty well and wallowed out. Ugh. I'm pretty sure that even if I have a proper washer and circlip that the whole thing will just pop out again. That said, I'm off to find my hardware (as an aside you can get anything hardware related from McMaster Carr pretty much overnight (even titanium). It's a fantastic resource LINK (http://www.mcmaster.com/).)

Now assuming that I'm doomed on the circlip (who knows, it might work)- what about the idea of tapping the "Head Wedge" to say 6mm and carrying a 6mm bolt and washer stack for extracting on the trail?

Cheers,

Kevin

[wrench177]

Yup- that's pretty close, the circlip is warped- I also discovered that the washer behind the circlip is missing and the notch for the clip is pretty well and wallowed out. Ugh. I'm pretty sure that even if I have a proper washer and circlip that the whole thing will just pop out again. That said, I'm off to find my hardware (as an aside you can get anything hardware related from McMaster Carr pretty much overnight (even titanium). It's a fantastic resource LINK (http://www.mcmaster.com/).)

Now assuming that I'm doomed on the circlip (who knows, it might work)- what about the idea of tapping the "Head Wedge" to say 6mm and carrying a 6mm bolt and washer stack for extracting on the trail?

Cheers,

Kevin
You know it odd, the EBB I worked on didn't have the washer either and the circlip never actually came out all the way. So....WTF. The PDF must be incorrect about that washer, which is stupid because you would want the bolt to push against a washer first and then the circlip. This could be good news though. If C'Dale milled out the slot for the circlip to be wide enough for a clip and a washer, you (in theory) should have enough room for a circlip that is double the thickness of what they spec'd. That should be plenty strong and resist warping when extracting the wedge.

Now, back to removal. I found a thread (http://forums.mtbr.com/showthread.php?t=222993&highlight=cannondale+eccentric) from a couple years ago and RickyD had a nice solution to a frozen wedge. Scroll down until you see the solution he came up with. It's nice, easy and doesn't require a percussive solution.

***Edit*** I just realized the side that is frozen is the non-threaded side. You'd have to tap in some threads in order to use the solution Ricky came up with. Sorry.

[smdubovsky]

... If C'Dale milled out the slot for the circlip to be wide enough for a clip and a washer, you (in theory) should have enough room for a circlip that is double the thickness of what they spec'd.

Thats not likely. There is no way to put a washer bigger than the ID down into the hole. So the goove will only be wide enough for the circlip. The only reason that will go down the hole is that it can be compressed.

FWIW, the circlip thickness shouldn't have much impact. If there is a proper close tolerance washer in between, it will put the clip in almost pure shear. W/o the washer, the rounded edges of the SHCS will bend the clip instead.

Just out of curiousity, whats the ID of the bore and thickness of the clip?

[kevinwilliams]

That's exactly how I freed the threaded side- worked like a charm, no fuss, no muss. I have no qualms about threading the unthreaded side- I just worry that the fresh threads won't stand up to the pressure since they won't be heat treated. On the trail I just have to carry a M5x08X20 plus washers and an M6x08x20 plus washers... oh and a pin spanner... and a crank puller (to get at both wedges)...

The funny part is that my other gonzo "home built" SS requires basically a whole tool set to keep going so lugging around "only" the above tools will seem light ;-)

We don't do this (SS) because it is easy...

[kevinwilliams]

Bore ID is about 10mm, clip thickness... well that would require a mic. (bu it's pretty robust)- I'll have to check it out tonight, need it to replace the clip anyway

[wrench177]

You may want to dump the C'Dale EBB and get a Busnell. (http://www.bushnelltandems.com/)

Not cheap, but, has to be better than carrying around a whole toolbox when you want to ride.

[wrench177]

Thats not likely. There is no way to put a washer bigger than the ID down into the hole. So the groove will only be wide enough for the circlip. The only reason that will go down the hole is that it can be compressed.

Right, what was I thinking. :confused2:

[kevinwilliams]

oooo I like the physics of the Busnell better, more BB shell contact too. I guess I'll buy one after I destroy this C'dale moster by tapping it...

[smdubovsky]

I just worry that the fresh threads won't stand up to the pressure since they won't be heat treated.

Cutting threads doesn't affect heat treat.

[philvw]

Since the non-drive side is already loose, and can move, instead of trying to get the drive side wedge OUT. What about getting the ebb IN ?? If you tap on it using a block of wood, or a pvc pipe fitting with a notch where the wedge is, all you need is enough to free it up. The loose side is already free and wont hold you up. Will the ebb travel that way or is something restricting it? It probably just needs a mm to get the wedge free.

[drevil]

Since the non-drive side is already loose, and can move, instead of trying to get the drive side wedge OUT. What about getting the ebb IN ?? If you tap on it using a block of wood, or a pvc pipe fitting with a notch where the wedge is, all you need is enough to free it up. The loose side is already free and wont hold you up. Will the ebb travel that way or is something restricting it? It probably just needs a mm to get the wedge free.

Brilliant. Let us know if this works, Kevin.

[kevinwilliams]

I out trickied myself- in order to access the wedge bolt without pulling the chain ring I reversed the whole BB some time ago (why it wasn't designed this way is beyond me)- thus, the assembly exits on the non-drive side and is held firmly in place by the threaded wedge. I did try removing the torx bolt on the non-drive side (bolt entry side) that holds the whole thing in and beating on it- it might have worked had I not gone caveman on the whole thing first- in a fit of pique, I shoved a 4mm X 80 bolt through the threaded end and beat on it with a framing hammer... after bending 4 bolts the wedge popped out. I took everything apart and lubed the heck out of, put it back together, rode about a block and tried to take it out again... hahahaha... stuck again :bangshead: but at least this time it's stuck in a ridable position.

To make this complete and useful for other C'dale eccentric sufferers I found the following:
1. The circlip is junk- in my case the bore was too wallowed out to hold it in place, even after I fabricated a small enough washer to fit behind it there was no lip to hold the clip against outward force.
2. Using a 5mm bolt plus washers as an extractor on the threaded wedge works great... on the threaded side
3. Lube the everlasting heck out of it (not that that helped in this case but I'm pretty sure that you have no hope if it's dry in there!)
4. If you destroy the wedge bolt (by say beating on it with a framing hammer) the replacement is PN 91292A197 at http://www.mcmaster.com/
5. As is, I'm walking if my chain tension is off on the trail- to make this trail-fixable I'm going to tap the unthreaded side with an 8mm and carry two small bolts and a stack of washers for easy extraction.
6. This thread has both a link to the tech manual and a blow-up diagram

Thanks all! I'm the guy carrying a framing hammer and a full bike shop around on the trail...

Cheers (and time to go RIDE!!!),

Kevin