I'm upgrading from 105 triple crankset to ultegra triple on an '01 Trek 2200. Can/should I continue to use my current 105 BB which seems fine (smooth, no noise)? If I should change it to ultegra, how can I figure out which one to get since both a 68 x 118.5 and a 70 x 118.5 are listed at supergo for use with triple cranks.