A chuck for inflating a tire having a Presta valve includes a valve engagement device defining an aperture with a central axis and a diameter, the valve engagement device movable radially with respect to the central axis to increase and decrease the diameter of the aperture. A locking device can engage with the valve engagement device to lock the valve engagement device in a selected radial position with respect to the central axis of the aperture. The chuck can include a seal positioned within the valve engagement device, the entire seal moving radially with the valve engagement device.