Understanding OEM Tire Sizes
Every vehicle leaves the factory with a specific tire size chosen by the manufacturer to optimize handling, ride comfort, fuel economy, and safety. This is called the OEM (Original Equipment Manufacturer) tire size.
When it's time to replace your tires, you have three options:
- Exact replacement: Use the same size as your current tires. Safest and simplest option. Use our lookup tool to confirm.
- Plus sizing: Install a larger wheel with a lower profile tire while keeping the overall diameter similar. Common for appearance upgrades. Use our comparison tool to evaluate.
- Minus sizing: Install a smaller wheel with a taller sidewall, often done for winter tire setups to improve ride and reduce cost.
Plus Sizing Guidelines
When upgrading to larger wheels, keep the overall tire diameter within ±3% of the original size to avoid speedometer errors and clearance issues:
- Plus 0: Same wheel size, different tire width or aspect ratio
- Plus 1: Increase wheel diameter by 1 inch, decrease aspect ratio
- Plus 2: Increase wheel diameter by 2 inches, further decrease aspect ratio
Our Tire Size Comparison tool automatically calculates diameter differences and warns you if you're outside the safe range.
What If My Size Isn't Listed?
Our database covers the most popular vehicles sold in the US from 2018-2026. If your vehicle isn't listed, check your driver's door jamb sticker or owner's manual for the factory tire size. You can also use our Tire Size Comparison tool to evaluate alternative sizes.