Important note about using PF30-SHIM adapters with certain SRAM PF30 bottom brackets
Many SRAM PF30 bottom brackets use proprietary bearings with a 43.5mm OD and a 31mm ID. A black plastic reducer is inserted into the bearing to reduce the ID down to 30mm, and also serves as a dust shield, completely covering the outer face of the bearings. The overall width of these bottom brackets is too wide when used with our PF30-SRAM adapters. Please use our Universal BB adapters for Shimano, which are thinner than the PF30-SHIM, and allow for more adjustability.
SRAM PF30 bottom brackets with this configuration are easy to identify, but require the removal of your cranks. With the cranks removed from the BB, if there is a plastic "top hat" looking reducer (shown in photos below) inserted into the bearing, that completely covers the outer face of the bearing and the inner race, you have one of these BBs.