chainline/bb/crankset help?
05-25-09, 09:34 PM
#1
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chainline/bb/crankset help?
I'm building a fg conversion for the first time, and well, nothing's really lining up right.
So I need help with the chainline and that's pretty much it I think!
In the rear, I have a chainline of 38mm. followed Sheldon's guildlines.
Problem:
Bottom bracket is seized, so I need a new bb.
However, I bought a used crankset, and so I need to find something that matches that crank, with the correct spindle length?
Here's a picture of the crankset on the current bb.
It seems okay..? does that mean I need to get the same spindle length?
and does the spindle length end at the end of the square taper? or at the end of the bolts..? :S
If other info are required in order to pinpoint which bb I'd need, let me know!
Thanks in advance!
So I need help with the chainline and that's pretty much it I think!
In the rear, I have a chainline of 38mm. followed Sheldon's guildlines.
Problem:
Bottom bracket is seized, so I need a new bb.
However, I bought a used crankset, and so I need to find something that matches that crank, with the correct spindle length?
Here's a picture of the crankset on the current bb.
It seems okay..? does that mean I need to get the same spindle length?
and does the spindle length end at the end of the square taper? or at the end of the bolts..? :S
If other info are required in order to pinpoint which bb I'd need, let me know!
Thanks in advance!
05-25-09, 09:43 PM
#2
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Run a chain on the current setup. You can visually inspect whether or not the chainline is grossly off. It doesn't look bad at all from the picture
05-25-09, 09:45 PM
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looks straight enough.
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Food for thought: if you aren't dead by 2050, you and your entire family will be within a few years from starvation. Now that is a cruel gift to leave for your offspring. ;)
https://sanfrancisco.ibtimes.com/arti...ger-photos.htm
05-26-09, 07:44 AM
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38mm chainline is real narrow. It will limit the size of the chainring up front that you can fit without running into the chainstay.
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05-26-09, 12:09 PM
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This is crazy talk. The only way to get your chainline right is to measure. You can solve some of it by respacing your rear wheel to get the cog closer to the dropout. In fact, this is pretty much your only option, unless you want to buy bottom brackets until you get it right.
As far as finding the right length spindle for your BB, check Sheldon's database.
It's not easy, but you want to get it right within a mm or 2. Throwing your chain on a fixie is not fun.
As far as finding the right length spindle for your BB, check Sheldon's database.
It's not easy, but you want to get it right within a mm or 2. Throwing your chain on a fixie is not fun.
