A Beginner’s Guide: How to Read Tire Sizes Correctly
Posted on September 11, 2025
If you’ve ever looked at the sidewall of your car’s tire, you’ve likely noticed a series of numbers and letters—something like 205/55R16 91V. At first glance, it may seem like a random code, but in reality, these markings tell you everything about your tire’s size, load capacity, and performance rating. Understanding how to read tire sizes correctly is essential for choosing the right replacement tires and ensuring your vehicle’s safety. At Momentum Tyre Service, we help drivers make informed choices by breaking down what these markings mean in simple terms.
Why Knowing Tire Sizes Matters
Selecting the wrong tire size can affect your car’s performance, fuel efficiency, and even safety. Properly fitted tires improve handling, braking, and comfort, while mismatched tires may lead to uneven wear or mechanical issues. By learning how to read tire sizes, you can confidently pick the right option for your car, SUV, or truck.
Breaking Down a Tire Size Example
Let’s take the example 205/55R16 91V and break it down step by step:
1. Tire Width (205)
The first number represents the tire’s width in millimeters. In this case, the tire is 205 mm wide from sidewall to sidewall. Wider tires often provide better grip, while narrower ones may offer better fuel efficiency.
2. Aspect Ratio (55)
The second number shows the aspect ratio, or the tire’s height compared to its width. Here, 55 means the height is 55% of the width. A lower ratio (like 40 or 45) means a shorter sidewall for sportier performance, while a higher ratio gives a more comfortable ride.
3. Tire Construction (R)
The R stands for Radial construction, which is the most common type of tire today. Radial tires are built with layers running radially across the tire, offering durability and comfort.
4. Wheel Diameter (16)
This number shows the diameter of the wheel (rim) in inches. So, the tire is designed to fit a 16-inch rim. Using the wrong wheel size can make the tire impossible to mount.
5. Load Index (91)
The load index represents how much weight a tire can safely carry. In this case, 91 corresponds to about 615 kg per tire. You’ll need to match or exceed your vehicle manufacturer’s recommendation.
6. Speed Rating (V)
The speed rating indicates the maximum safe speed for the tire under proper conditions. A V rating, for example, means the tire can handle speeds up to 240 km/h. Other common ratings include H (210 km/h) and W (270 km/h).
Other Important Tire Markings
In addition to size codes, you may also notice:
- M+S (Mud and Snow): Indicates all-season capability.
- 3PMSF (Three-Peak Mountain Snowflake): Designed for severe winter conditions.
- DOT Code: Shows compliance with safety standards and includes the manufacturing date.
- Treadwear, Traction, Temperature Ratings: Provide performance details under different conditions.
How to Choose the Right Tire Size for Your Car
- Check the Owner’s Manual – The manufacturer lists recommended tire sizes.
- Look at the Door Placard – Found on the driver’s side door frame, it shows approved sizes, load, and pressure.
- Match Performance Needs – Do you drive mostly on highways, city roads, or off-road? Choose tires based on your driving habits.
- Consult a Professional – At Momentum Tyre Service, our experts ensure you pick the safest and most efficient tire for your vehicle.
Common Mistakes When Choosing Tire Sizes
- Mixing Tire Sizes: Different sizes on the same axle can cause handling issues.
- Ignoring Load Index: Choosing a lower load index than required can be dangerous.
- Over-Sizing for Looks: While bigger tires may look good, they can reduce fuel economy and strain suspension parts.
Momentum Tyre Service: Your Trusted Partner
At Momentum Tyre Service, we don’t just sell tires—we help you make the best decision for your vehicle. Our services include:
- Professional tire inspection and fitting
- Wheel alignment and balancing for even wear
- Wide range of premium and budget-friendly tire brands
- Expert advice tailored to your car and driving style
Conclusion
Learning how to read tire sizes correctly empowers you to choose the right tires, ensuring safety, comfort, and performance on the road. With the right knowledge, you’ll avoid costly mistakes and extend the life of your tires.
For expert guidance and premium tire services, trust Momentum Tyre Service—your reliable partner in keeping your vehicle safe and road-ready.
