Tire Size Calculator

The numbers indicate tire width (mm), aspect ratio (height as % of width), construction type (R=Radial), and wheel diameter (inches). For example, 225/45R17 means 225mm width, 45% aspect ratio, radial construction, 17-inch wheel.

Yes, but it's recommended to stay within 3% of your original tire diameter. Larger differences can affect speedometer accuracy, handling, and may cause clearance issues with your vehicle.

Larger tires make your speedometer read lower than actual speed, while smaller tires make it read higher. This is because speedometers calculate speed based on wheel rotations, and tire size changes the distance traveled per rotation.

Aspect ratio is the tire's sidewall height as a percentage of its width. A 45 aspect ratio means the sidewall height is 45% of the tire's width. Lower numbers mean shorter sidewalls (sportier), higher numbers mean taller sidewalls (more comfortable).

Generally yes, especially for all-wheel drive vehicles. Having different tire sizes can cause drivetrain damage and affect handling. Some performance cars have staggered setups (wider rear tires) from the factory, which is designed into the vehicle.

The "R" stands for Radial construction, which means the tire's internal cords run perpendicular to the direction of travel. Almost all modern passenger vehicle tires are radial tires, offering better handling, fuel efficiency, and durability.