A catheter shaft includes an inner layer of a first polymeric material, an intermediate layer of a second polymeric material, an outer layer of a third polymeric material, a first wire reinforcing layer encapsulated between the inner and intermediate layers, and a second wire reinforcing layer encapsulated between the outer and intermediate layers. Typically, the first wire reinforcing layer includes one or more metallic wires helically wound in one direction and the second wire reinforcing layer includes one or more metallic wires helically wound in the opposite direction. The intermediate layer is bonded to the inner and outer layers, as by extruding layers over one another or by thermal lamination or reflow bonding. Typically, the intermediate layer has a larger yield strain and/or a lower flexural modulus and/or a lower durometer than at least one of the inner layer and the outer layer.