Tire Size Comparison Calculator

When you change your tire size, your speedometer reading will be affected because it's calibrated based on the original tire's circumference. A larger tire has a greater circumference, so it covers more distance per revolution. This means your actual speed will be faster than what your speedometer shows. Conversely, smaller tires make your actual speed slower than indicated. Our calculator shows exactly how your speedometer will be affected at different speeds.

Plus sizing is a common practice of increasing the wheel diameter while decreasing the tire's sidewall height to maintain approximately the same overall diameter. For example, if your OEM size is 215/65R16, a plus-one size might be 225/55R17. This approach gives your vehicle a sportier look with wider tires and larger wheels, while maintaining proper speedometer calibration and clearance.

Metric tire sizes like 225/65R17 are read as follows: 225 is the width in millimeters, 65 is the aspect ratio (sidewall height as a percentage of width), R indicates radial construction, and 17 is the wheel diameter in inches. For example, in a 225/65R17 tire, the sidewall height is 65% of 225mm, and it fits on a 17-inch rim.

Metric sizes (like 265/70R17) use millimeters for width and a percentage for sidewall height, while inch-based sizes (like 33x12.50R15) directly state the overall diameter and width in inches. Metric sizes are common for passenger vehicles and some light trucks, while inch-based sizes are popular for off-road and all-terrain applications.

Yes, but there are important considerations: larger tires may rub against fenders or suspension components, affect handling, and alter your speedometer readings. We recommend staying within 3% of your original tire's overall diameter unless you're making other modifications to accommodate larger sizes. Use our tire comparison calculator to see how different sizes compare before making a purchase.