What size tires are on the 2018 BMW X1?
R18 front tires & 255/40R18 rear tires. Several car manufacturers commonly use 235/40 R18 tires on their vehicles. If you own a vehicle from one of these brands, chances are you may need 235/40 R18 tires at some point. With the right 235/40 R18 tires, you can enjoy a safe, comfortable, and confident driving experience.