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Discussion Starter · #1 ·
I'm a beginner when it comes to maintenance, so I'll describe my problem as detailed as possible.

I've noticed that my front derailleur wasn't shifting properly. When I put my bike up on my stand, I looked closer and noticed my crank is wobbling ever so slightly when I turn the pedal. I took off the crank arm, and tugged on the crank arm that has the chain on it.. and saw that it moved freely side to side without any major force (I hope I'm explaining this right) Does this mean the bearings are no good? The part that says do not disassemble is not loose. Just a lot of play in between the crank and the BB.

Any thoughts? Thanks

~ Dura Ace.. bike is about one year old.
 

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No, if you took off the left arm then the right arm with the chainring will be loose. You have to preload the bearings from the left side, so you don't really know what, or if, anything is wrong. Most chainrings are not perfectly straight, so it might not even be a problem.
 

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TIghten up

talentous said:
I've noticed that my front derailleur wasn't shifting properly. When I put my bike up on my stand, I looked closer and noticed my crank is wobbling ever so slightly when I turn the pedal. I took off the crank arm, and tugged on the crank arm that has the chain on it.. and saw that it moved freely side to side without any major force (I hope I'm explaining this right) Does this mean the bearings are no good? The part that says do not disassemble is not loose. Just a lot of play in between the crank and the BB.

Any thoughts? ~ Dura Ace.. bike is about one year old.
DA BBs are adjustable - it's not really about bearing preload but truly is an adjustment with an adjustable (left) cup. The cup is held in place with a lock ring, so you need a lock ring spanner to do the work. You probably need to remove the left crank arm, tighten the adjustable cup just to the point where the axle play is removed, and then tighten the lock ring. Riding with a loose DA BB can damage the unit, so you want to get this sorted out ASAP.
 

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Discussion Starter · #4 ·
Found the Problem

android said:
No, if you took off the left arm then the right arm with the chainring will be loose. You have to preload the bearings from the left side, so you don't really know what, or if, anything is wrong. Most chainrings are not perfectly straight, so it might not even be a problem.
Android.... you were right... there was really no big problem. I've taken off the left crank before but I guess I didn't slide it in all the way. Either that or is came loose. Which meant the alignment for the right crank and chain was off. Lesson learned.. Thanks
 

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Kerry Irons said:
DA BBs are adjustable - it's not really about bearing preload but truly is an adjustment with an adjustable (left) cup. The cup is held in place with a lock ring, so you need a lock ring spanner to do the work. You probably need to remove the left crank arm, tighten the adjustable cup just to the point where the axle play is removed, and then tighten the lock ring. Riding with a loose DA BB can damage the unit, so you want to get this sorted out ASAP.
If this bike really is only a year old, then it does NOT have an adjustable BB. It's got the newish Dura Ace hollowtech or whatever it's called with the external cups and the hollow spindle attached to the drive-side crank. The closest it gets to adjustment is when you put the non-drive crank on, and even that's not really preload or anything--it's just snugging the crank arm against the bearing cup before tightening the pinch bolt that holds it on.
 
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