LexRides

safety_in_numbers · training wheels Joined: 12 Aug 2008 Posts: 32

I want to get a new crankset and bottom bracket for my Fuji fixed gear. How do i measure these parts so i can insure the new ones fit?

sailorjames · cutter Joined: 15 Nov 2007 Posts: 329

The way I'm used to doing it is mocking the drivetrain with any sized bottom bracket, 68 x ____ (you'll most likely have a 68mm shell) Throw your wheel and crank on, connect them with a chain, and see where your chain line is. Then get a larger or smaller bottom bracket as needed. This is pretty easy if you have spare bottom brackets lying around, which I know may not be the case for most people.

In the event you have no spare BB's around, I'd say go to grandpa Sheldon:
http://www.sheldonbrown.com/bbsize.html and get your metric ruler out.

I'm assuming also that you'll be using a square taper bottom bracket/crankset.

safety_in_numbers · training wheels Joined: 12 Aug 2008 Posts: 32

thanks dude, no extra bb so ill be measuring it i guess. thanks for the link, ive been lookin for that article all day.

safety_in_numbers · training wheels Joined: 12 Aug 2008 Posts: 32

oh yea, how do i know the manufacturer

mattypichu · hipster Joined: 27 Oct 2008 Posts: 52 Location: bike shop

You're looking more for the style of BB more than the manufacturer. The majority of bikes out there are going to have a square taper, their are a few other styles. Does your BB axle look like a tapered square shape? If yes, it's a "square taper" if not check back at Sheldon's site for more examples or take it into a shop. They should be able to tell you what size and style you have, if not what you need.
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