How To Read Tire Sizes

Choosing the right tires isn’t just about looks—it’s about safety, performance, and proper vehicle fitment. At Velgen Wheels, we know that understanding tire sizes can be confusing, especially when dealing with performance setups. If you want your Dodge Charger, Challenger, Mustang, or any performance vehicle to look and handle its best, knowing how to read tire sizes is essential.

Breaking Down the Tire Size Format

Most tire sizes follow a format like 275/40R20. Each section of this sequence represents a specific measurement that helps determine how the tire will fit and perform on your vehicle. Let’s break it down. The first number, 275, is the tire width in millimeters. This measures the distance from sidewall to sidewall. A wider tire offers more surface contact, which can improve grip, especially during aggressive driving or cornering. The second number, 40, is the aspect ratio. This represents the sidewall height as a percentage of the width. So, in this case, the sidewall height is 40% of 275mm. A lower aspect ratio means a shorter sidewall, which results in a stiffer ride and better handling. The “R” stands for Radial construction, which is the standard for modern tires. The last number, 20, is the wheel diameter in inches. This tells you the wheel size the tire is designed to fit.

Additional Markings to Know

Beyond the basic size, tires often have extra markings that provide important details. You may see something like 275/40ZR20 106Y. The Z indicates the tire is rated for higher speeds, while 106Y refers to the load index and speed rating. The load index tells you how much weight the tire can safely carry, and the speed rating tells you the maximum speed the tire is rated to handle. These ratings matter when upgrading your wheels and tires—especially when performance is your priority.

How Tire Sizes Affect Fitment

Not all tire sizes work with every wheel or vehicle. Too wide or too tall, and you’ll risk rubbing, inaccurate speedometer readings, or suspension clearance issues. That’s why it’s important to pair the right tire size with the correct wheel offset and width. At Velgen Wheels, we offer wheels specifically engineered for precise fitment on modern muscle cars and trucks. We’ll help you match tire sizes that not only fit but also perform and look incredible.

Plus Sizing and Performance Considerations

Plus sizing refers to using a larger diameter wheel with a lower profile tire to maintain the overall diameter of the original setup. For example, upgrading from an 18” to a 20” wheel might require a shorter sidewall to keep your speedometer accurate and preserve suspension geometry. Done right, plus sizing can enhance handling and aesthetics. Done wrong, it can negatively affect ride quality and component wear. That’s why our team is here to ensure every tire you choose complements your Velgen wheels perfectly.

Common Tire Size Mistakes to Avoid

One of the most common mistakes we see is choosing tires that are too wide for the wheel or too tall for the fender wells. This can lead to rubbing during turns or when hitting bumps. Another mistake is mismatching tire sizes between front and rear axles in a way that impacts traction control systems or all-wheel drive setups. Always consult an expert or reference your vehicle’s recommended specifications when upgrading your tires.

Conclusion

Understanding tire sizes empowers you to make better choices for performance, safety, and style. At Velgen Wheels, we’re not just about making your vehicle look good—we’re about making sure it drives at its best, too. Contact us today to find the perfect tire and wheel setup for your ride.