Tear-away and non-tear-away sheath introducers for catheters, methods for making such introducers, and methods for using such introducers are described. The sheath introducers contain movable valves that are encapsulated in a movable housing unlike conventional valves that are stationary. The movable housing allows the valve to move along the axis of the introducer. As the movable valve and housing travel along the axis, a portion of the hub protrudes past the valve and is exposed. The protruding portion of the hub contains a friction-free pathway for the catheter into the sheath introducer. The introducers can therefore be used with any catheter, regardless of the size or material, because of the reduced or eliminated frictional force between the catheter and introducer.