Ok...so you have BB30, PF30 or a Specialized OSBB frame, but you need to run a Shimano crank? No worries. Our Praxis Works Conversion BB is just what you're looking for. Made to fit in either BB30 or PF30 frame, the conversion BB is designed to be rock solid for a Shimano* Hollowtech II crank to be installed in your frame.* Designed for Shimano T 24mm Hollowtech II cranks. Some Race Face T, & FSAT. 24mm spindle cranks work also.