Many Ford vehicles have the two-part lug nuts. The lug nuts are enclosed by a chrome jacket to improve their appearance. These lug nuts tend to get moisture in between the nut and the jacket which eventually causes corrosion. The corrosion makes the lug nuts swell up to a point where the standard tire wrench will not fit. This means that the lug nuts must be replaced. This is a systemic design issue with these vehicles, and Ford should cover the cost of replacing the lug nuts.