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Discussion Starter · #1 ·
This seems like it would have an easy answer, but darn if I can come up with one. I have an 07 Trek Fuel EX9 and bought it frame only. I built it up using a 68X113 Octalink BB and spacers so that it wouldn't come in contact with my frame. The BB has been used for ohhhh 8 years and needs to be replaced. Though now that I'm shopping there doesn't seem to be anything between 113 and 118. Though if I used the 118 I wouldn't need spacers and might have the proper amount of clearance. As it stands I could barely get my pinky finger in between the crank arm (either) and the frame. The 118 or 118.5 will add 2.5-2.75mm per side.



Aaron
 

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Just out of curiosity, what kind of crank are you running that's an octalink with carbon arms?


I'd just get another 113 if that's been working for you. No sense changing your chainline and whatnot if there aren't any issues with the current setup?
 

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Discussion Starter · #4 ·
keen said:
I go by manufactures spec's, chainline spec. and clearance - It's not hitting, a finger is quite a bit of clearance.
Given I don't have manufacturer specs that why I'm here. If you notice it's not even a full finger more like less than 1/2 a pinky on a sz 10 gloved hand. Oh as for the crank this is a FSA carbon pro from 98 or 99, money well spent given it's lasted this long. Every descent BB I found new was close to $80 so I'm going the new route. I picked up an 09 XT for $199 shipped. I still need to know about where the chainline needs to be. As a home mechanic and shop mechanic (not certified) I never had to make a build from scratch with a BB.

Aaron
 

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Discussion Starter · #5 ·
In the event there is a method in which one determines the BB width needed please feel free to post up, just because It can't help me it might serve as a starting point for someone else.

Aaron
 

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Discussion Starter · #7 ·
Hardtails Are Better said:
It's all about chainline. There's a tool to measure it, your shop should have one.

Alternately, you can just eyeball it.
Yeah I'm with the eyeball crowd, though having to purchase multiple bb's just to get it right could suck.

Aaron
 

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Discussion Starter · #9 ·
So now your saying RTFM read the freakin manual. That is a good idea, but just for discussion sake my 98 or 99 cranks manual are long gone... oh screw it just eyeball it if it hits get a wider bb. Now that being said my new cranks 09 XT with ginormous outboard bearing are width adj. with spacers and should be easy to determine the proper chainline.


Aaron
 

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Your new XT will work for sure. Since the spindle is integrated into the crank arm, there isn't any different bb width to worry about.


I'm just saying that since you already have the current crank set up, you could look at the chainline, and if it's off, get a different length bb to accomodate. Most manufacturers are pretty good about putting old manuals on their website, so you can often look things up there.


This sort of thing is a good case for going through your lbs rather than mail ordering everything. If you've got a decent one (not a given, I know), they'd have been able to help you through this.
 

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Discussion Starter · #11 ·
Gotta love the lbs I worked at one for nearly a decade and always appriciated people coming in to spend their hard earned money. I do find where I live in S. FL most shops cater to the roadies which leaves me wanting more parts than they stock. So in an effort to see parts and save some cash I purchase like so many others online. I know I know had I not I might have saved the economy, but it was a us seller so that helps someone. I have quite a bit of the tools from my mech. days so I'm good when it comes to bike setup.

Aaron
 

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This thread is very confusing. Since you bought a new crankset that can fit on a 68mm or 73mm bottom bracket shell you should be covered in that department. Next is the spindle length which I believe was you original question. "what size spindle length do I need?" If 113 is too small or you are not comfortable with the space between the chainstay and the crankarm then get a 118, 2.5mm either way is not that much unless you are Lance Armstrong and it has to be perfect. Octalink is a Shimano proprietary product that wont work with FSA so you will need to get an ISIS splined bottom bracket if it is going to work. Lastly, if you run the new cranks they are set up for a 50mm chainline which would be the same as running a 118 bottom bracket spindle, your 113 spindle length would equate to a 47.5mm chainline which I don't think you can get with the new outboard style bottom bracket. I hope this clarifies some of the issues. Check the late Sheldon Brown's website for more details. :thumbsup:
http://www.sheldonbrown.com/chainline.html
R
 

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Discussion Starter · #13 ·
Well everything you said was true except for the FSA cranks they did make Octalink FSA's unbeknown to most it's kinda like big foot. No no doesn't have to be perfect thats what the swing and cable adj. are for. The spindle link is now a non issue as I'm getting new cranks and it turned more fyi than help me as it was originally. Here the ellusive FSA octalinks.





Aaron
 
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