Understanding Tyre Codes and Markings

Understanding Tyre Codes and Markings

When you look at the sidewall of your tyre, you’ll notice a series of numbers and letters like 205/55 R16 91V. To most drivers, it looks like a confusing code. But in reality, these markings tell you everything about your tyre’s size, performance, and safety limits. Let’s break down what tyre codes mean and why they matter.

Tyre Size Example: 205/55 R16 91V

205 – Tyre Width

• The tyre’s width in millimeters (from sidewall to sidewall).
• A wider tyre = better grip, but lower fuel efficiency.

55 – Aspect Ratio

• The ratio of tyre height to width, shown as a percentage.
• In this case, the tyre height is 55% of 205mm.
• Lower ratios = sportier handling, higher ratios = more comfort.

R – Construction Type

• R = Radial (most common).
• Radial tyres have layers of fabric running radially across, giving strength and flexibility.
• B = Bias Ply (used in some trucks and older vehicles).

16 – Rim Diameter

• The wheel/rim size in inches.
• You must match the rim size when replacing tyres.

91 – Load Index

• Indicates how much weight one tyre can carry.
• 91 = 615 kg per tyre (you can check load index charts for details).

V – Speed Rating

• Maximum speed the tyre can safely handle.
• V = 240 km/h.
• Other examples: H = 210 km/h, T = 190 km/h, W = 270 km/h.

Other Common Markings

• M+S (Mud + Snow): Indicates better grip on mud and snow.
• 3PMSF (Three-Peak Mountain Snowflake): Certified for winter performance.
• Tubeless/Tubetype: Shows whether the tyre is tubeless or requires an inner tube.
• DOT Code: U.S. Department of Transportation code showing manufacturing details, including the week and year of production (e.g., DOT 2319 = 23rd week of 2019).
• Rotation Arrows / “Outside–Inside”: Directional or asymmetric tyres show how they must be mounted.

Why Tyre Codes Matter

✅ Ensures you buy the right replacement tyre.

✅ Helps maintain proper load capacity and speed safety.

✅ Prevents fuel wastage and uneven wear.

✅ Avoids mismatched tyres that can affect braking and handling.

Understanding tyre codes and markings isn’t just for car enthusiasts-it’s essential for every driver. The numbers and letters on your tyre tell you exactly what your vehicle needs in terms of size, load, and performance.

👉 Next time you’re buying tyres, check these codes carefully to make a safe and smart choice.