I think my bottom bracket has worn and I would like to replace it. I was looking at the Shimano 105 BB. BikePedia lists the size as 68mm, which is fine, but there seems to be another dimension. I can get
68 x 109 mm or
68 x 118 mm. Is it possible to work out which size I need without removing the current BB?
update I'm not sure which of the below answers is correct. In the end I bought a SM-BB6700 Bottom Bracket BC1.37 which worked fine (techdocs here).