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mikelikebike said:
About to replace a 110 mm driveside crank arm with a 113 mm arm
Am I likely to run into any significant chain line issues bringing the crank/rings in 3mm? There are no clearance issues, as far as I can tell.
Check your terminology. Crank arms are not that short. Spindles are but you can not just replace one side. Going to a longer spindle moves the rings out, not in.
 

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Old man on a bike
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Like Shiggy says, check your terminology, crank arm lengths that short would be pretty damn weird. If you're referring to mixing arms from different cranksets, that require different spindle lengths, and you're going to one an arm from one that normally requires a 113 spindle instead of a 110 spindle, then you're effectively moving it in 1.5 mm theoretically chainline-wise (3mm for the whole spindle, so only 1.5mm on each side) with the same 110 bb spindle, and it's probably not a great big deal as long as you want to mix different crank arms and have the clearance and it's not going to have other issues from the mismatch. Why do you want to do this?
 

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Discussion Starter · #5 ·
Yeah, sorry, I just read what I wrote, and it was not clear at all.

I stripped the threads on the pedal spindle hole on my drive side crank and it couldn't be helicoiled. I didn't feel like buying a whole new crank at this point, so I found a replacement crank arm with the same length and BCD (175/94), the only difference is that the new crank arm was on a 113mm spindle and my bottom bracket spindle length is 110. So, yes, thanks Bikinforlife, it would actually only come in 1.5mm, not 3 (forgot to half the difference).

While it's not ideal or a long term fix, I just wanted to assure that it wasn't going to present any problems - and from what I'm reading, it seems it should be fine.
 

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mikelikebike said:
Sorry again, I thought it was apparent this time what I meant. Arm length/bcd (175/94). No?
No. Arm length is one thing. BCD (or PCD) is usually expressed as two numbers with a slash, yes but the first number represents the outer/middle rings normally and the second number for the granny (if it's not a triple then there's usually only one bcd to mention). I'm guessing if you have a 94 you've got a 94/58. Try this http://www.sheldonbrown.com/gloss_bo-z.html
 

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Discussion Starter · #9 ·
Ha. Okay. Yes, I realize that there are two BCD measurements on a 3 ring crank. But I did actually mean what I said. Those were the two dimensions I was speaking to on the crank arm.

I'm new to bike speak. The info is all there in my head, I'm just not quite speaking your language just yet.

Thanks for the help, though.
 

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Chainline and....

crank arm desing can be confusing. Just because your new crank arm was on a 113mm bottom bracket doesn't mean that it will through your chain line off on the 110mm bb. It depends on what chainline the crank arm was desinged to give with a given spindle length. Also the desing of the frame can have a bearing as chainring/seat stay clearance could become an issue. Usually a change of 1.5mm isn't that big of a deal and as noted previously may only require some minor front derailleur adjustments one way or the other. Without knowing the model and manufacture of the crank and bottom bracket it's impossible to say what problems you may encounter. Even knowing everything about the components it would be difficult as there are no difinitive references that give the resulting chainline of all possible combinations of bottom brackets and cranks. So all you can do is try. You most likely won't have any problems that are not easily solved.
 
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