Originally Posted by homelessjoe

bottom brackets come in different lengths.........103mm ...106mm .....on and on.........your crank requires a specific BB length.......your chain line will be off and it might not shift if you dont use the right length..............not all years of 105s take the same BB length......look up your new crank and see what size of BB is required......only one size will work.....you will need to measure [mic] your old one to se what size it is ........my opinion........A BB upgrade is more important than a crank upgrade.........