|   BottomBracket sizing | gonzo
Jan 1, 2004 7:09 PM | | I've got a frame I would like to build up but don't know what size bottom bracket spinle to use. Any rule of thumb for deciding length?
My guess is I should use a 113mm. thanks in advance.....
gonzo |
| re: BottomBracket sizing | GregR..
Jan 2, 2004 5:08 AM | | Basically, there are two dimensions to be concerned with when sizing a BB. The shell width, and the spindle length.
The shell width is frame dependent, so measure the width of the BB shell.
The spindle length is crank dependent, and will be determined by the make/model of crank you choose and what your preferred chainline is. Mots MTBs like a 47.5mm to 50.0mm chainline.
For example: LX and XT square taper cranks use a 107mm to 113mm BB spindle length, where the 107 gives you an approximate chainline of 47 and 113 gives you a chainline of 50mm (note with sq. taper cranks, chainline is not an exact science, and deformation of the taper affects chainline).
So measure your shell, and decide what cranks you will be using, and determine what the preferred chainline is.
G |
| thanks nm | gonzo
Jan 2, 2004 8:54 AM | | |
| Say I want a Brand X crank... | PT
Jan 2, 2004 2:03 PM | | How do I find out what any given crank needs as far as the spindle length? I've looked for such information at manufacturers web sites, but haven't found it. I'm building up a frame for my wife and would like to pick up something off from ebay, but I don't know what length spindle on the bottom bracket to get |
| You can contact the manufacturer, or... | GregR..
Jan 2, 2004 5:17 PM | | look here: http://www.sheldonbrown.com/bbsize.html
Its not complete, but has quite a few.
G |
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