A medical balloon catheter including a shaft comprised of a cross-wound coil tube and a sleeve surrounding the cross-wound coil tube. The cross-wound coil tube includes a monofilament inner coil disposed within a monofilament outer coil. The inner and outer coils are wound in opposite pitch directions. In at least one embodiment, at least one of the inner and outer coils includes a tapered distal section having a tapered diameter. In at least another embodiment, the inner coil extends distally beyond the distal end of the outer coil, providing increased flexibility in a distal portion of the shaft. An inflation balloon is attached to the distal end of the shaft. The shaft includes an inflation lumen formed through the inner coil and a wire guide lumen formed through the distal portion of the shaft and extending through the chamber of the balloon.