Tire Size Calculator

Compare tire sizes, calculate speedometer error, check compatibility, and find plus-sizing options. Professional tire analysis for safe and optimal performance.

Tire Size Analysis

Original Tire Size

Example: 225/60R16 = Width: 225mm, Aspect: 60%, Rim: 16 inches

New Tire Size

Example: 235/55R17 = Width: 235mm, Aspect: 55%, Rim: 17 inches

Speedometer Analysis (Optional)

What speed shows on dashboard

GPS or radar confirmed speed

Compatibility Guide

Compatible±3% difference
Caution3-5% difference
Not Recommended>5% difference

Reading Tire Sizes

Example: 225/60R16
  • 225 = Width in millimeters
  • 60 = Aspect ratio (%)
  • R = Radial construction
  • 16 = Rim diameter (inches)
Aspect ratio is the sidewall height as a percentage of the tire width.

Performance Tips

Lower aspect ratios improve handling but reduce comfort
Wider tires provide better grip but may increase road noise
Plus sizing improves appearance but costs more
Always maintain same overall diameter for compatibility

Understanding Tire Sizes and Compatibility

Why Tire Size Matters

Changing tire sizes affects more than just appearance. Even a 3% change in overall diameter can impact your speedometer accuracy, fuel economy, and vehicle handling. Plus-sizing (larger wheels with lower-profile tires) improves handling but may reduce ride comfort.

Your vehicle's ABS, traction control, and stability systems are calibrated for specific tire dimensions. Significant changes can affect their performance and potentially void warranties.

Safe Sizing Guidelines

  • • Keep overall diameter within ±3% of original size
  • • Check wheel well clearance at full steering lock
  • • Ensure adequate clearance for suspension components
  • • Consider load rating and speed rating requirements
  • • Verify tire pressure monitoring system compatibility

Common Tire Size Changes and Their Effects

Plus Zero

Same wheel size, different tire dimensions. Maintains ride quality while potentially improving performance.

Plus One

Increase wheel diameter by 1 inch, decrease sidewall height. Improved handling, slightly firmer ride.

Plus Two

Increase wheel diameter by 2 inches, lower profile tires. Better handling but firmer ride, higher cost.

Wider Tires

Increased width without diameter change. Better grip but potential for increased road noise and cost.