Nick Payne wrote:
When comparing the same size of deep groove radial vs angular contact bearings, the angular contact bearings have about 30% greater load capacity. This is because more balls can be loaded into angular contact bearings because the raceways are ground so that the balls only make contact with one side. This allows the other side of the raceway to be left relatively open so more balls can be loaded. But this also means that a single bearing can't support axial loads in both directions, unlike a deep groove radial bearing. Your hub/BB has to be designed for angular contact bearings if you want to use them.