Described are valve stems for wheels or other pressure vessels that may be installed from the exterior of a wheel or pressure vessel without access to the interior, pressure retaining areas. The valve stem may include a body with a barrel and taper. A neck may be between the body and a base that includes a flange, a flange landing, and an air aperture. An air channel runs vertically through the valve stem to allow air to pass from one side of the valve stem to another with a valve core or other flow control device. The base of the valve stem may include a groove that allows the valve stem to be installed into a hole by twisting such that the groove may ride along the rim of the hole and guide the valve stem into a fully seated and sealed position.