Tire Size Calculator
Compare tire sizes, diameter, width, and sidewall height. Check speedometer error and clearance differences between two tires.
Tire 1 (Original)
Tire 2 (New)
Understanding Tire Specs
Tire sizes like 205/55 R16 may look cryptic, but they follow a simple formula:
- Width (205): The width of the tire in millimeters from sidewall to sidewall.
- Aspect Ratio (55): The height of the sidewall as a percentage of the width. Here, 55% of 205mm.
- Rim (16): The diameter of the wheel in inches.
Why Tire Diameter Matters
Changing tire size affects your vehicle's gearing and speedometer accuracy.
- Larger Diameter: Your speedometer will read slower than you are actually going. You may also rub against fender liners.
- Smaller Diameter: Your speedometer will read faster than you are actually going. Engine RPM will be higher at cruising speeds.
- Safety: A diameter difference of more than 3% is generally not recommended as it can affect brake failure systems (ABS) and traction control.
? Frequently Asked Questions
Most manufacturers recommend keeping the total tire diameter within 3% of the original factory size to prevent issues with the speedometer, odometer, and ABS system.
Width clearance depends on your specific vehicle's wheel well and suspension components. A tire size calculator only checks dimensions, not physical fitment on your car.
Revolutions Per Mile is how many times the tire rotates to travel one mile. A smaller tire spins more times, which registers as 'more miles' on the odometer than a larger tire.