Tire Size Comparison
Compare tire dimensions and discover how changing tire sizes affects your speedometer accuracy.
Original Tire
New Tire
16"
STOCK
18"
NEW
Difference
+4.40%
Diameter Change
+1.09"
Speedometer Calibration
Adjust Indicated Speed to find actual travel speed
When Speedo Reads
60 MPH
Actual Ground Speed
62.6 MPH
Safety Warning: Your diameter difference is 4.40%. Experts recommend staying within 3% of the factory tire size to avoid ABS/Traction control issues and transmission stress.
Visualizing Your Upgrade
- Enter the Stock Tire dimensions (Width, Aspect, Rim).
- Enter the Target Tire dimensions for your upgrade.
- Observe the Visual Silhouette to see the height and width differences.
- Check the Speedometer Error % to see how much your speedo will be off.
- Verify against the Safety Warning if the difference exceeds 3%.
Frequently Asked Questions
What is the 3% rule for tire size?
Most automotive experts recommend keeping the overall diameter of your new tires within 3% of the original factory size. Exceeding this can interfere with ABS, traction control, and transmission shift patterns.
How does a larger tire affect my speedometer?
A larger tire has a greater circumference, meaning it travels further in one rotation. If your tires are larger than stock, your speedometer will read slower than your actual ground speed.
What do the numbers 205/55R16 mean?
205 is the tire width in millimeters. 55 is the aspect ratio (sidewall height as a % of width). 16 is the wheel rim diameter in inches. 'R' stands for Radial construction.
Will wider tires affect my fuel economy?
Generally, yes. Wider tires increase rolling resistance and aerodynamic drag, which can slightly decrease your MPG (miles per gallon).
Key Benefits
- Dynamic visual tire profiles
- Calculates precise speedometer error
- Side-by-side metric comparison
- Works for both US and Metric sizes
- 100% private — your car specs stay local
- Mobile-optimized for garage use
Privacy-First Architecture
100% Local Processing
Unlike traditional online tools, Tire Size Comparison processes your data entirely within your browser. Your files, numbers, and private info never reach our servers, ensuring absolute confidentiality.
Lightning Fast Speed
By eliminating the need for server uploads and downloads, we provide near-instant results. This technical approach saves bandwidth and provides a seamless user experience on both mobile and desktop.
Professional Grade Utility
The Tire Size Comparison is part of the Toolkits Plus suite—a comprehensive collection of professional-grade utilities designed for modern digital workflows. Whether you're a student, professional, or hobbyist, our tools provide accurate, verified results without the clutter of traditional "thin" web applications.