Tire Size Comparison Calculator

Compare different tire sizes to understand differences in diameter, circumference, and speedometer accuracy. Essential for upgrading or changing tire sizes on vehicles.

About Tire Size Comparison Calculator

Understanding Tire Sizes

Tire sizes are specified in a format like "225/45R17", where 225 is the width in millimeters, 45 is the aspect ratio (height as a percentage of width), and 17 is the wheel diameter in inches. Changing tire sizes can affect vehicle handling, speedometer accuracy, and overall performance. It's crucial to choose compatible sizes that maintain proper clearance and don't significantly alter the original specifications.

Size Relationships

Width Effects

Traction characteristics
Handling response
Hydroplaning resistance
Rolling resistance

Aspect Ratio Impact

Ride comfort
Sidewall flexibility
Overall diameter
Cornering stability

Fitment Considerations

Physical Fit

Wheel well clearance
Suspension clearance
Brake caliper space
Fender clearance

Performance Impact

Speedometer accuracy
Gear ratio effects
ABS calibration
Fuel economy

Frequently Asked Questions

How much tire size difference is safe?

Generally, it's recommended to stay within 3% of the original tire's overall diameter. Larger differences can affect vehicle handling, speedometer accuracy, and safety systems. Always consult your vehicle manufacturer's specifications and a tire professional.

Will different size tires affect my speedometer?

Yes, changing tire diameter affects speedometer readings. Larger diameter tires make the speedometer read slower than actual speed, while smaller tires make it read faster. Each 1% change in diameter results in approximately 1% speedometer error.

Learn More

Tire Size Calculator Guide NHTSA Tire Safety