Bicycle Mechanics - correct bottom bracket sizing

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slopvehicle
05-23-07, 02:13 PM
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.

tellyho
05-23-07, 08:01 PM
I'm assuming the shell width is 68mm; to get the right spindle length, look up your crankset on Sheldon's site.
Raiyn
05-23-07, 08:04 PM
The crankset determines the BB spindle length.

Sheldon Brown
05-23-07, 08:21 PM
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.The frame will definitely use a normal 68 mm English/ISO thread BB.

Measure the chainline as illustrated at http://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

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| One measurement is worth 50 expert opinions |
| --Howard Sutherland |
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