The first requirement for replacing tires is that they must be able to carry the vehicle's weight. However, in many cases this will allow for approximately a 3/4 inch change in diameter. Sport utility vehicles and trucks are generally engineered so that they can handle up to 15 percent on an oversized tire. While many people rely upon a mechanic or Tires Lancaster professional to recommend the best tires, it is a good idea for car owners Tire Wrenches Manufacturers to have a basic understanding of what size tires are best for their vehicles.