How do I find out my bottom bracket length?

[The_Grouch]

1994 Saracen Eiger - lets just say some idiot fitted a bottom bracket that is shorter than the orginal one, how do I find out what the original size was? Can I tell from measuring the bottom bracket shell?

Thanks!

 

[poweredbypies]

Measure the bb shell width, and what cranks you putting on it?

 

[firedfromthecircus]

As pbp has alluded there are two measurements. The shell width which is dictated by the frame, and the axle width which matches the crankset.

There is a list on Sheldons site I think.

edit: Link here.

 

[The_Grouch]

Thanks guys, I should have thought to look on sheldons site

I think I'll have a go at measuring the chainline, then removing the bottom bracket to see what I've got installed, and then hopefully from that info I can work out how much longer it needs to be!

 

[klasse]

optimal spindle length will also depend on which crank you select