Customers are often curious about the 'XL' designation that they see next to the size of certain tires. Because XL is commonly used as an abbreviation for extra large, many of them think that the XL tire will be a different size. When talking about tires, XL really means extra load. These tires can use higher air pressure to support more weight than a standard tire of the same size.
If you want to see whether your current tires are standard or extra load, you can check the service description on the tire's sidewall. An extra load tire will have a higher load index than a standard tire. For more information on properly understanding the letters and numbers on your tire's sidewall, read "Sidewall Markings."
If your car normally uses a standard load tire, it is allowed to use an XL tire. They may have a slightly stiffer sidewall compared to their standard load counterparts, but the difference is not usually obvious. If your car comes with an XL tire, it is recommended to stick with XL options. However, standard load tires can still be used provided they meet the vehicle's GAWR (Gross Axle Weight Rating) requirements. The vehicle's placard, usually located in the driver's doorjamb, lists the front and rear GAWR. With two tires per axle, the tire load rating must be at least half of the GAWR. The vehicle placard will also list the service description of the original tires.
To learn more about tire service descriptions, take a look at "How to Read Speed Ratings, Load Index, & Service Descriptions."