Bottom bracket

[baron von greenback]

I new to building bikes can't get my head round BB I measure the hole for a BB and it's 35mm then the lads says is it 68mm or 73mm shell were are them measurements coming from do you double the original size help appreciated

 

[MattiThundrrr]

68 and 73 mm refer to the width of the bottom bracket shell

 

[baron von greenback]

Ha ha well that clears that up I thought when I said I need a 125mm length that was that so you have to have the right measurement for the bike shell then the extra length on either side not just a 125mm full length if that makes sense I been looking at it wrong I thought it was the width of hole then length of overall spindle cheers matti