Specialized OSBB – Engineering Guide

A question that crops up frequently is with regards to Specialized's OSBB bottom bracket and what size it is exactly. The short answer is OSBB comes in 3 variants which are all called OSBB. 46x61, 42x68 and 46x73. A summary table is below, with the detailed drawings below that. Variant (Diameter x Width) (mm)ApplicationDescription46 x 61RoadFrame tolerances are the same as PF30. It is extremely narrow42 x 68RoadThis has exactly the same dimensions as BB30 and is designed for 6806 or 61806 bearings…

Close Menu