Getting into my mid 60's and climbing hills and mountains isn't getting any easier. I'm going to replace my drivetrain, starting with my crankset, going from a 53-39 to a 50-34 (and the rear with a 12-30). My CF bike has probably 20,000-25,000 miles on it. No problems with the BB but since I'm doing the crankset, do you recommend getting a new BB?