Praxis M30 Press Fit bottom brackets are designed to be a proper bottom bracket (BB) for installing Turn M30 spindle based cranks in either; • BB30, • PF30, • BB86, • BB92 • Specialized’s OSBB frames. Our patent pending design keeps the cartridge bearings outboard of the frame right on Shimano™ spec for greater rigidity and free of frame/c-clip tolerance issues that other systems deal with.Simply press in the longer non-drive-cup, then the shorter drive cup threads into it. As the drive cup threads in, our trademark Collet system expands to a precise limit evenly dispersing pressure for a super tight fit. With both cups connected and our collet set exactly to spec, there is no chance the bearings can come out of alignment or wiggle/walk out of the frame. This design also uses a compressible o-ring on the non-drive side cup to compensate for frame shell width discrepancies.