This adapter sleeve provides a mechanical fit between a shaft with a plain cylindrical surface and a bearing bore with a taper, allowing the bearing to be mounted at any point along the shaft without a stepped or threaded seat. It has a bore diameter of 90.0 mm and a net mass of 1.608 kg, in standard design, supplied complete and ready for mechanical mounting. The sleeve simplifies bearing installation and removal on plain shafting, transmitting the clamping force generated by the locknut to expand the bearing's inner ring onto the taper, which sets the internal radial clearance during fitting. Because the fit is achieved through the sleeve rather than a machined tapered shaft, it suits applications where shaft tolerances are kept simple and where the bearing position along the shaft needs to be adjustable.