The present disclosure relates to fluid machines, especially compressors, more especially screw compressors. More particularly the present disclosure describes a fluid machine comprising at least one rotor, the rotor including a rotor drive shaft extending from the rotor, a housing in which is mounted the rotor, and at least one bearing insert which mounts around the rotor drive shaft at a first end of the rotor and which includes at least one bearing within it and attaches to the housing. The present disclosure also describes bearing inserts suitable for use on such fluid machines
