Tire Size Calculator
Compare tire sizes visually, calculate speedometer error, and check if alternative tires will fit your vehicle.
Enter Tire Sizes
Original Tire
225/45R17
Comparison 1
235/45R17
Size Comparison
Visual comparison of tire sizes (not to exact scale)
Comparison Results
How each tire compares to your original 225/45R17
Diameter Change
+0.35"
Speedometer Error
+1.4%
Overall Diameter
25.33"
Rev/Mile
796
When speedometer shows:
Original Tire Specifications
Overall Diameter
24.97"
Sidewall Height
101.3mm
Circumference
78.45"
Rev/Mile
808
Frequently Asked Questions
Common questions about tire sizes
How do I read tire size numbers?
225/45R17 means: 225mm width, 45% aspect ratio (sidewall height as % of width), and fits a 17" rim.
How much size difference is safe?
Stay within 3% of original diameter to avoid speedometer error and maintain proper handling.
Will larger tires affect my speedometer?
Yes - larger tires make your speedometer read slower than actual speed. Smaller tires read faster.
Can I change rim size?
Yes, as long as overall tire diameter stays similar. This calculator helps find equivalent sizes.
Disclaimer: This calculator provides estimates based on standard tire size formulas. Actual fitment depends on your specific vehicle, suspension, and fender clearance. Always consult a tire professional before making changes.