Tire Size Comparison
Upgrade your wheels without the guesswork. Compare your current tire size to a new one and see how it affects your speed and ground clearance.
When driving 60 MPH, your actual speed is 60.7 MPH.
| Dimension | Current | New | Diff |
|---|
What do the numbers mean?
I genuinely believe that tire sizing is the most cryptic part of car maintenance. Take a 225/45 R17 tire: **225** is the width in millimeters. **45** is the "aspect ratio," meaning the sidewall height is 45% of the width. **R17** means it fits a 17-inch wheel. When you change any of these, you change the total diameter of the wheel.
Speedometer Error: Your car's computer counts how many times the wheels rotate to calculate speed. If you put on larger tires, each rotation covers more ground, so your speedometer will read slower than you are actually going. This is a common way to get a speeding ticket after lifting a truck!
Safety Guidelines:
- Clearance: Ensure the new tires don't rub against the fender or suspension when you turn the steering wheel all the way.
- The 3% Rule: Most mechanics recommend keeping your tire diameter within 3% of the factory size to avoid stress on the transmission and brakes.
- Load Index: Make sure your new tires can handle the weight of your vehicle!