Is this the thread together Wheels BB? If so I would not worry that it is not a press fit on the side you thread in, non-drive side I believe. I installed on of the Wheels BBs a few weeks ago. From my observation what holds it together is the torque after tightening the two halves together. As indicated above clean up the burrs coat the shoulder of the Wheels non drive side cup with anti seize and the threaded section and tighten to specs.