A belt roller for a safety belt having a belt coil for winding and unwinding the safety belt. The roller includes a lockable locking base which is connected to the belt coil and which is suitable for blocking the belt coil in the event of an abrupt rotation of the belt coil in the belt unwinding direction. The roller also includes a force transmission element which couples the belt coil and the locking base in a locking position and is inactive in an unlocking position. The force transmission element has a base member and a shearing portion which can be sheared off.