Methods, systems, and devices for wireless communications are described that provide for selection of different sets of transmission beams by a user equipment (UE) for establishing beamformed communications with a base station. Each transmission beam of a first set of transmission beams may have corresponding uplink random access channel (RACH) resources. A UE may monitor for transmission beams from a base station and select a first transmission beam of the first set for communications with the base station. As part of a connection establishment, the base station may provide configuration information that indicates a second set of transmission beams that includes each transmission beam of the first set of transmission beams and at least an additional transmission beam. In some cases, the additional transmission beam may be mapped to a first RACH resource that also corresponds to a first transmission beam of the first set of transmission beams.