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Old 03-26-11, 01:34 PM   #1
DCwom
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Eccentric - How much force?

I finally got around to trying to adjust our eccentric today (sync chain sagging) and the thing won't budge, its a Burley. I backed out the center allen a half turn but the thing won't budge. I've put allens into the side holes to try and move it but no luck and I'm afraid to give it too much force. Anyone have any guidance?
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Old 03-26-11, 02:05 PM   #2
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Burley used several types of eccentrics over the years. You might have to be a bit more specific (or perhaps post a photo) to help us out. If the center bolt serves to tighten/back out a wedge, you will have to loosen it much more than 1/2 turn. The bolt head must first contact the "keeper" (nut or c-clip) and then push on the wedge.

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Dave
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Old 03-26-11, 02:15 PM   #3
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DCwom - Looking at your previous thread which included a picture, bikeriderdave is right on. We have a similar (actually 2) eccentrics on our daVinci. The wedge-type eccentrics are a very good design. keep turning until you feel resistance which is the point at which you're disengaging the wedge. Another turn or so and the eccentric should spin freely.
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Old 03-26-11, 05:32 PM   #4
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Originally Posted by rdtompki View Post
DCwom - Looking at your previous thread which included a picture, bikeriderdave is right on. We have a similar (actually 2) eccentrics on our daVinci. The wedge-type eccentrics are a very good design. keep turning until you feel resistance which is the point at which you're disengaging the wedge. Another turn or so and the eccentric should spin freely.
I was wondering how far to back out the allen, after a half turn it was very free then it became difficult again around a full turn. I was concerned that it was a captive bolt and I didn't want to force it out of its captivity.
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Old 03-26-11, 05:49 PM   #5
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I've never taken one apart, but when you're tightening the bolt you're forcing the two opposing parts of the wedge apart. When you loosen the bolt and it starts to become "tight" again keep turning and the eccentric will after a turn or so I would think become complete free in the bottom bracket. I wouldn't worry about loosing a captive bolt. You can always take a crank arm off in any event and pull the whole eccentric out.
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