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· Game on, b*tches!
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Discussion Starter · #1 ·
I just bought a new crank and BB. I usually install them myself but since the new one is an external BB and I don't have the tool, I was going to have my LBS do it for me. $20, not abig deal. then they asked if I wanted it faced etc. I asked if it was necessary. they said "yes". (Of course they did; $25 more.) So I bagged it. Is it really necessary to do that? I had it done when the bike was new, but I've changed several BB's since than and not had it done with no ill effects....
 

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My new Felt ZC frame specifically says facing is not needed and shouldn't be done. On the other hand, I've heard that it is not uncommon (maybe even generally recomended?) to face the BB shell for an external BB.
 

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You really should only need to face the frame once. Unless the frame specifically says not to face it, it should be done if using an external BB. The cups rely on the BB shell for alignment, so facing takes care of that. Bad alignment could mean the bearings wear out too quickly and/or clicks and creaks can happen.

It used to be that frames were faced in the factory but that doesn't seem to be true anymore. Manufacturers rely on the shop to do it which means it usually doesn't get done unless the customer asks for it.
 

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BB 's definitely have to be faced square for the cups, and therefore the bearings to sit square. That can be done by the framebuilder or factory during production, or by the first person building it up, as part of the "frame prep". Usually facing is done after painting to ensure that uneven paint thickness isn't a problem, but it can be done first with good QC during painting.

That said, once a BB shell is faced, there's almost never a reason to do it anew. They don't magically warp or become unsquare. If the OP knew that the BB shell was faced he should have informed the mechanic and declined the job.

In the mechanics defense, it used to be assumed that BBs were properly faced when installing new BBs on used bikes. But during the era of cartridge BBs held on with lock rings facing was less critical and often not done, so today you can't take it for granted than a used bike has a faced BB.
 

· Game on, b*tches!
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Discussion Starter · #7 ·
I had them do it when I 1st got the frame, several yrs ago. Guess I'll save the $$ and skip it. Thanks all.
 

· duh...
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Kram said:
I had them do it when I 1st got the frame, several yrs ago. Guess I'll save the $$ and skip it. Thanks all.


well yeah, if it was done initially as a new frame it should not have to be done again
 

· classiquesklassieker
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Kram said:
I had them do it when I 1st got the frame, several yrs ago. Guess I'll save the $$ and skip it. Thanks all.
Facing a BB is an irreversible process, you lose some part of the BB every time you have it done. So do it exactly only once (properly). Otherwise you may end up with a BB that is too short for some cranksets (such as the Campy Ultra-Torque).

Are they going to get you to have the threads chased, now? :p
 

· Game on, b*tches!
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Discussion Starter · #10 ·
Nope; I'm buying the tool and doing it my own d*mned self :)
 

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Kram said:
Nope; I'm buying the tool and doing it my own d*mned self :)
If you've got a bench grinder with a 10"+ coarse wheel it's a really easy job. Oh wait...you might need a rat tail file too.
 
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