Rule No. 8: Make sure your tires fit your vehicle

Size matters.

That’s rule No. 8 in our Ten Rules of Tires series. If your tires fit your vehicle, you’ll reap a number of benefits, including safety, efficiency and comfort.

Why Is Tire Size Important?

When you’re buying tires, your first priority should be purchasing a quality driving solution that will do its best to keep you safe. Trusting a tire dealer is a great way to make a confident purchase decision.

But then, you’ve got to decide which tire size to install. Of course, tire dealers can help with that choice. You can also find your vehicle’s recommended tire size in your driver-side door jamb or owner manual. Our user-friendly website allows you to find the right tire size for your make, model and engine type.

Choosing the right tire size will help you get the best performance out of your vehicle and your tires. Your car was built with a specific size range in mind. If your tires are too small, they’ll be overtaxed and you’ll risk a blowout or excessive wear. If they’re too large, they won’t be as efficient on the road. The wrong size can also lead to a less comfortable ride and even inaccurate measurements on your speedometer and odometer.

How Do I Decode My Tire’s Size?

Your tire size looks something like this: 205/55R/16. What does that code mean?

The first three numbers – “205” in this case – represent the width of your tire in millimeters. The next two – “55” here – is the percentage of your tire’s sidewall’s height in relation to its width. The “R” means that it’s a radial tire – this should always be the case for a passenger tire. The final two numbers (“16” in this example) are the diameter of your rims. Sometimes, you’ll see a “P” at the beginning of the tire size. This just means the tire is meant for a passenger vehicle.

Other Factors to Consider

Size matters, but it’s not the only important metric to consider. You’ll also want to examine a tire’s load index and speed index. The load index tells you the tire’s maximum capacity (in kilograms). The speed index notes its maximum speed (in kilometers per hour). As you might imagine, high-performance tires typically have higher speed indexes, while SUV and truck tires carry bigger load indexes.

Electric and hybrid vehicles are typically heavier and require tires with higher load indexes. Nokian Tyres makes great tires for eco-friendly vehicles – our products have low rolling resistance, which means those heavier loads don’t result in poor fuel efficiency.

Here’s a more detailed breakdown of the markings on a tire’s sidewall.

To read the full list of our Ten Rules of Tires, click here. To learn more about our products and premium nature, visit