My pa has a Mondeo Mark4 with wheels 235/45/r17 and the alloys are 7.5 inches wide. He wants to put on steel wheels on the front to accommodate winter treads but the width is 7 inches. What size tyres would he need to put on the front to match the size on the front. If anyone could tell me or direct me to a website that would calculate it for my I would be grateful.