The 235/40R18 tire size is one you’ll find on the Chrysler PT Cruiser, Ford Focus, Hyundai Elantra, older-generation Honda Accord and Volvo C70, among others. If you’re driving something that is rolling on 235/40R18 tires, you are probably looking for all-season tires that offer predictable handling, a comfortable ride, good road manners, and year-round traction on wet or dry pavement. Or, perhaps you like to really get the most out of your vehicle’s handling and cornering potential with ultra-high-performance and summer tires. Just remember that UHP tires use a softer, “stickier” tread formulation that stiffens in colder weather, and shouldn’t be used when it’s colder than about 45 degrees Fahrenheit outside.