Rapid exchange catheters having improved pushability and trackability due to a support mandrel disposed within the inflation lumen. The mandrel is secured at the proximal end of the catheter shaft while the free distal end extends beyond the proximal guidewire port. In an alternative embodiment, the catheter shaft further comprises a sleeve in the inflation lumen that secures a distal section of the support mandrel. The distal end of the mandrel extends beyond the sleeve.
