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Discussion Starter · #1 ·
So I decided to upgrade the whole drivetrain of my bike, including new SLX cranks. I brought my bike to the lbs and had them face the bottom bracket shell. Using calipers, I measure the shell width at 64mm. You guys think that they took off too much, or is this within spec? I'm unsure as to what to do next. I've already spoken w/ the lbs, they said they'll look into it, but i dont know what to expect. Thanks.
 

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ups and downs
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It should be 68mm, so I'd say removing 4mm off would be a bit much. Usually all that's necessary is removing the paint to get it back to a parallel 68mm, it's rare to have a BB shell that's so far out of parallel that it needs that much material removed.
 

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ride like you stole it
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I would take a look at the bottom bracket and cranks once they're installed, maybe take a feeler gauge or something and see if they're is any extra space.
 

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noMAD man
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I'm not saying it can't be done, but anyone done any BB facing with something like the Park tool? I have, and I'd say you'd have to almost do this intentionally to remove 4mm of aluminum off the BB shell. 4mm is a ton. What did they do?...let the new junior high guy loose with the tools?
 

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Unfit Norwegian
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That's a ridiculous amount of material removed. I sure hope they make it up to you.

I don't know if I'd accept anything less than a (killer deal on a) replacement frame.
 

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Discussion Starter · #9 ·
So the lbs and I have contacted Giant directly, and both of them decided the frame was still within spec, and that spacers are to be used. I guess I'm worried that according to Shimano instructions for a 68mm shell, 2 spacers are to be used on the nondrive side and 1 on the drive side. I wonder how many I'm gonna need now at 64?
 

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Unfit Norwegian
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What spec is that, I wonder?

The BB spacers are 2.5mm each, and if you KNOW they removed the same amount of material on both sides, then MAYBE that'd be OK with one more on each side. Then again, it may also be too tight, and the threads on the BB cups might not be long enough to reach through all those spacers. I don't think I'd be OK with that. Sorry. ...But if they fix it and everything works fine, I guess It could work out OK if you're not as OCD as me. ;)
 

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Live 2 Ride
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I would cry foul and fight for a new frame...
 

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Unfit Norwegian
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I'd check with Giant too. I find it strange that they'd think that a 64mm bb shell is OK.

805-267-4600

I bet Shimano don't like 64mm BB shells for their 68/73mm BBs. If you give them a call, they might back up your claims that your frame is no longer usable.
 

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4mm? Might as well be a friggin yard. I don't think I'd want whatever hamfist was operating the facing tool anywhere near my frame with a cutting tool of any kind.

Also, I'd rather think that the BB manufacturer would be have the final say on whether the shell is within spec or not. Talk to Shimano.

For the X-type BB I'm running, 67.25mm is the bottom end of the tolerance range - though with a note that out of tolerance shells can be spaced back in.
 

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Discussion Starter · #14 ·
I've checked with Giant's technician and they agreed with the bike store that its still usable, and not enough to warrant having the frame replaced or any type of compensation. I'll give Shimano a call and see.
 

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The sad part is that using standard BB spacers, they'd have to shave it all the way down to 63mm as the BB spacers are in 2.5mm increments. The tweaky 1mm BB shims are all designed for thin steel BB shells, and they don't mate well with standard BB spacers.
 

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rockyuphill said:
The sad part is that using standard BB spacers, they'd have to shave it all the way down to 63mm as the BB spacers are in 2.5mm increments. The tweaky 1mm BB shims are all designed for thin steel BB shells, and they don't mate well with standard BB spacers.
It's tempting to have a machinist just turn and grind some spacers the correct size. Seems a little cleaner than having a bunch of spacers stacked up.
 

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Discussion Starter · #17 ·
I spoke with Shimano and their tech seemed pretty sympathetic, but pretty much gave the same response in that I just should use more shims. After installing the crankset using the supplied 3 spacers, I still have a 2.55mm gap left, so I guess I need to add one more 2.5mm spacer, and maybe one of these?

http://www.treefortbikes.com/482_333222346897__HollowtechII-Bottom-Bracket-Spacer-0.7mm.html

Giving a total of 5 spacers, 4 at 2.5mm and 1 thin spacer. As long as I get the chain inline and theres enough spacers so that the external bb cups come in contact with something, it should work right? At this point I just want to have a working bike, the frame itself is already pretty beaten up after 2 race seasons. This is all on my 2006 giant anthem if i never mentioned, thanks guys for all the responses.
 

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noMAD man
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Unless there was an absolute last ditch effort to save the frame because of some unholy damage at the BB shell, I think it's downright criminal that someone at a shop shaved 4mm off your frame's BB shell. I do my own work, but if a shop did this to a frame of mine without just cause, they'd be supplying another frame, or they'd be paying in glass breakage...or worse. I'm still not getting why this happened.
 

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Discussion Starter · #19 ·
Their explanation to the Giant tech was that there were "inconsistencies" in the bb shell that required the 4mm removal so that both sides would be parallel. Giant's techn sided with the lbs and now I have to use a bunch of spacers.
 

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leemr2 said:
Their explanation to the Giant tech was that there were "inconsistencies" in the bb shell that required the 4mm removal so that both sides would be parallel. Giant's techn sided with the lbs and now I have to use a bunch of spacers.
Personally if I had to use a couple of extra spacers, I don't think I would care about that from a technical standpoint. You' should be able to get your chainline dialed in just fine. But I would be pissed that 4mm was cut off of my frame without a valid explanation. What kind of "inconsistencies" could require that much material to be removed? There could be a reason (let's give the benefit of the doubt here) but if so let's hear it from the dude who faced the frame. You deserve more than a vague explanation for a drastic modification like that.
 
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