Tire Size Calculator
Compare two tire sizes to understand the differences in diameter, width, sidewall, and speedometer reading.
Real-time Results
Change in overall height
When speedometer reads 60 mph
When speedometer reads 100 km/h
Detailed Tire Specs
Direct comparison of dimensions
| Item | Value |
|---|---|
| Original Diameter Overall height of old tire | 25.86 in |
| New Diameter Overall height of new tire | 25.72 in |
| Ride Height Change How much your car will be raised/lowered | -0.07 in |
| Safety Check Safe to upgrade. | Pass |
Why Choose Tire Size Calculator
The Tire Size Calculator allows you to visually and mathematically compare two different tire sizes. When upgrading your wheels or tires, it is crucial to maintain an overall tire diameter within 3% of your OEM specification. This calculator breaks down the differences in width, sidewall height, circumference, and shows exactly how the new tire will throw off your car's speedometer reading.
- ✓Compare two tire sizes side-by-side to ensure proper fitment
- ✓Calculate the exact error your new tires will introduce to your speedometer
- ✓Ensure your new tire diameter stays within the safe 3% threshold of the OEM size
How to Calculate
- 1Enter the Width (e.g., 225), Aspect Ratio (e.g., 65), and Wheel Diameter (e.g., 17) for your current/OEM tire.
- 2Enter the specs for the new tire you are considering.
- 3Review the differences in diameter, width, and sidewall.
- 4Check the Speedometer Error to see how fast you will actually be going when the dial reads 60 mph.
Frequently Asked Questions (FAQ)
What happens if I change my tire diameter too much?
Changing your tire diameter by more than 3% from the factory size can cause several issues. It will throw off your speedometer and odometer, it can mess with your anti-lock braking system (ABS) and traction control, and it may cause the tire to rub against the wheel well or suspension components.
What do the numbers on my tire mean? (e.g., 225/65R17)
The first number (225) is the width of the tire in millimeters. The second number (65) is the aspect ratio, meaning the sidewall height is 65% of the width. The 'R' stands for Radial construction. The last number (17) is the diameter of the wheel (rim) in inches.
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