correct bottom bracket sizing

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05-23-07 | 02:13 PM

slopvehicle

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correct bottom bracket sizing

What's the correct bottom bracket width for this setup?

- Miyata 914 road frame ('91 or so)

- Sugino VP double crankset

I think the current BB may be too wide-- installed a new wheelset last night and the chainline seems way off.

Thanks!

Oh-- I should add that this is essentially a frame-up build, but I figured I could get away with using the previously installed BB. I'll be pulling it tonight to see what size the currently installed bb is.

05-23-07 | 08:01 PM

tellyho

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I'm assuming the shell width is 68mm; to get the right spindle length, look up your crankset on Sheldon's site.

05-23-07 | 08:04 PM

Raiyn

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Joined: Jul 2002

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From: St. Petersburg, FL

Bikes: 2003 Specialized Rockhopper FSR Comp, 1999 Specialized Hardrock Comp FS, 1971 Schwinn Varsity

The crankset determines the BB spindle length.

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05-23-07 | 08:21 PM

Sheldon Brown

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From: Newtonville, Massachusetts

Bikes: See: https://sheldonbrown.org/bicycles

Quote:

Originally Posted by slopvehicle

The frame will definitely use a normal 68 mm English/ISO thread BB.

Measure the chainline as illustrated at https://sheldonbrown.com/chainline on the present BB. Normally, a double should have a 43.5 mm chainline.

If it's off, you can easily calculate how much longer or shorter the next BB needs to be once you have taken appropriate measurements.

Sheldon "Numbers" Brown

Code:

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|  One measurement is worth 50 expert opinions    |
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