Knowing how to read these markings helps you choose a tire suited to your vehicle, your driving habits and local road conditions, whether you drive in the city, on the highway, in the rain or in winter. Understanding the tread pattern also helps you better evaluate comfort, grip, water evacuation and proper installation practices.

1. Decoding Tire Size: Example 215/55R18

Tire size is often the most visible piece of information. Let’s use 215/55R18 as an example.

• 215 - width: the width of the tire in millimetres, from one sidewall to the other. The higher this number, the wider the tire.
• 55 - aspect ratio: the sidewall height expressed as a percentage of the tire width. In this case, the sidewall height is 55% of 215 mm.
• R - construction: means Radial, the most common tire construction used today.
• 18 - diameter: the rim diameter in inches. This tire must be mounted on an 18-inch wheel.

A lower aspect ratio, such as 35 or 40, usually indicates a low-profile tire, often used on vehicles with a sportier driving feel.

2. Understanding Load and Speed Ratings

After the tire size, you will often find a number followed by a letter, for example 91V. These two elements indicate the tire’s load capacity and maximum safe speed rating.

Load Index

The load index corresponds to the maximum weight the tire can support when properly inflated. For example, a load index of 91 means the tire can support up to 1356 lb.

Important: never install a tire with a load index lower than the one recommended by your vehicle manufacturer.

Speed Rating

The speed rating indicates the maximum speed at which the tire can safely operate.

• T: up to 190 km/h
• H: up to 210 km/h
• V: up to 240 km/h
• W / Y: over 270 km/h, depending on the exact specification

3. What Do XL and LT Mean on a Tire?

Some markings indicate that the tire is designed to carry heavier loads or to equip light trucks and utility vehicles.

• XL - Extra Load: a reinforced tire that can handle higher inflation pressure and heavier loads than a standard tire of the same size.
• LT - Light Truck: a tire designed for pickup trucks, utility vehicles and heavier vehicles. Example: LT245/75R16.

LT tires generally have stiffer sidewalls and a more robust construction than passenger vehicle tires.

4. The DOT Code: How to Know a Tire’s Year of Manufacture

The DOT code indicates, among other things, the tire’s manufacturing date. The last four digits tell you the week and year the tire was produced.

Example: 0720

• 07: week of manufacture
• 20: year of manufacture

This tire was therefore manufactured during the 7th week of 2020.

Good to know: at 4Tires.ca, we make sure not to ship tires with a DOT code older than 2 years.

A recent DOT of 1 or 2 years is not something to worry about. When a tire has been properly stored for 1 or 2 years, it does not affect its real service life once installed on the vehicle. What matters most is choosing a tire that meets the manufacturer’s recommendations and suits your driving needs.

5. UTQG Specifications: Treadwear, Traction and Temperature

UTQG, or Uniform Tire Quality Grading, is an American rating system found on most summer and all-season tires. It provides information about durability and performance.

• Treadwear: indicates tread wear. A tire rated 600 should theoretically last twice as long as a tire rated 300.
• Traction: rated AA, A, B or C. It measures the tire’s ability to stop on wet pavement in a straight line.
• Temperature: rated A, B or C. It indicates the tire’s resistance to heat generated at high speed.

Good to know: winter tires generally do not display a UTQG rating. This is normal because the system is designed to compare tires tested under standardized conditions, mainly on dry or wet pavement. Winter tires are instead evaluated based on cold-weather performance, snow, ice and winter driving conditions.

6. Symmetrical, Asymmetrical, Directional and Non-Directional Tires: What Is the Difference?

The tread pattern directly influences handling, comfort, noise level, water evacuation and wet-road performance. Tires can be symmetrical or asymmetrical, but also directional or non-directional.

Symmetrical Tires

A symmetrical tire has the same tread pattern on the inner and outer sides of the tire. This type of design is common on many passenger vehicles because it offers a good balance of comfort, durability and quiet driving.

• Comfort: generally provides a smooth and quiet driving experience.
• Durability: often promotes even wear when the tires are properly maintained and regularly rotated.
• Versatility: suitable for everyday driving, city driving and highway use.

Asymmetrical Tires

An asymmetrical tire has a different tread design between the inner and outer sections of the tread. The inner section is often designed to better evacuate water, while the outer section is optimized for cornering stability and grip.

• Wet-road performance: the inner area helps evacuate water and reduce the risk of hydroplaning.
• Handling: the outer area provides better stability when cornering.
• More dynamic driving: often used on premium touring tires, performance tires or sport-oriented tires.

Important: asymmetrical tires must be installed the right way, with the correct side facing outward on the vehicle. Look for the Outside and Inside markings on the tire sidewall before installation.

Directional and Non-Directional Tires

In addition to being symmetrical or asymmetrical, a tire can also be directional or non-directional. This characteristic indicates whether the tire must rotate in a specific direction or whether it can be installed in either direction of rotation.

Directional Tires

A directional tire has a tread pattern designed to rotate in one specific direction. Its pattern often forms a V-shape or arrow-like design, which helps channel water, slush or mud away from the tire.

• Installation: the tire must follow the rotation direction indicated by an arrow on the sidewall.
• Performance: it often provides better water evacuation and good grip on wet pavement.
• Rotation: it is generally rotated from front to rear on the same side of the vehicle, unless the tire is removed from the wheel.

Non-Directional Tires

A non-directional tire can rotate in both directions. It does not have a mandatory rotation direction, which makes installation and tire rotation easier.

• Installation: the tire can be mounted in either direction of rotation, unless otherwise indicated by markings such as Inside or Outside.
• Versatility: it is well suited to everyday driving and standard road use.
• Rotation: it allows more flexibility when rotating tires, according to the manufacturer’s recommendations.

Important: a directional tire installed in the wrong direction may lose effectiveness, especially in rain, snow or slippery conditions. Always check the rotation arrows or markings visible on the sidewall before installation.

In general, symmetrical and non-directional tires are good choices for drivers looking for comfort, durability and easier rotation. Asymmetrical and directional tires are better suited for drivers who want improved wet-road grip, more precise handling and more responsive performance.

How to Choose the Right Tires for Your Vehicle

Before buying new tires, always check the manufacturer’s recommendations. They are usually found in the owner’s manual or on the sticker located inside the driver’s door frame.

For safe, economical driving suited to your region, consider tire size, load index, speed rating, year of manufacture, season and your driving habits.

FAQ About Tire Markings