Decoding Car Tyre Markings: Everything You Need to Know
Your car’s tyres are more than just rubber circles—they’re the only part of your vehicle that touches the road. Understanding the markings on a tyre’s sidewall can make a huge difference in choosing the right ones, ensuring safety, performance, and longevity. In this guide, we’ll break down every key marking, including tyre size, load index, speed rating, and the all-important DOT number, while diving into HT and MT tyres and why freshness matters.
What Do Tyre Markings Mean?
Tyre markings are like a tyre’s DNA, offering vital information about its size, capacity, speed, and age. Here’s how to read them:
1. Tyre Size Markings
Example: 205/55 R16 91V
205: The tyre’s width in millimeters.
55: Aspect ratio—sidewall height as a percentage of tyre width.
R16: Radial construction with a 16-inch rim diameter.
91V: Load index (91 = 615 kg per tyre) and speed rating (V = up to 240 km/h).
Tip: Always check your car’s owner manual for the recommended tyre size to ensure optimal fit and performance.
2. Load Index and Speed Rating
The Load Index is the maximum weight a tyre can safely carry when fully inflated, while the Speed Rating is the maximum speed it can sustain.
Load Index Example:
91 = 615 kg per tyre.
With four tyres, the total capacity is 615 kg x 4 = 2460 kg.
Speed Rating Chart:
Speed Rating
Max Speed (km/h)
H
210
V
240
W
270
Why It Matters: Choosing tyres with the correct load index and speed rating is critical for safety and handling. Overloading tyres can lead to failure, while a mismatched speed rating can compromise stability.
3. The DOT Number: Why Freshness is Key
The DOT Number (Department of Transportation) reveals a tyre’s age and manufacturing details.
Example: DOT T7RD 3C8L 2423
T7RD 3C8L: Plant code and tyre type.
2423: The tyre was manufactured in the 24th week of 2023.
Why It Matters:
Rubber degrades over time, even if unused. A general rule is to replace tyres every 5–6 years to prevent cracks, reduced grip, and blowouts.
Freshness Checklist
1–2 Years Old: Safe to buy and use.
3–5 Years Old: Monitor condition; inspect for ageing.
6+ Years Old: Replace immediately, regardless of tread wear.
Pro Tip: Always check the DOT number before buying to ensure you’re getting fresh stock. Avoid tyres older than 6 months for maximum performance.
4. Treadwear, Traction, and Temperature Ratings
Example: TREADWEAR 400 TRACTION A TEMPERATURE B
Treadwear: Longevity rating; higher numbers mean longer life.
Traction: Wet stopping ability (AA > A > B > C).
Temperature: Heat resistance (A > B > C).
Tip: For daily use, look for tyres with balanced treadwear and traction ratings. Performance tyres might prioritize grip over longevity.
HT vs. MT Tyres: What’s the Difference?
Tyre type matters as much as size and ratings. Here’s the difference between Highway Terrain (HT) and Mud Terrain (MT) tyres:
Highway Terrain (HT) Tyres
Best For: City driving, highways, and light off-road use.
Features:
Smooth tread for quiet rides.
Better fuel efficiency and longer tread life.
Load Index: Generally higher, making them ideal for SUVs and family cars.
Mud Terrain (MT) Tyres
Best For: Off-road adventures, muddy trails, and rocky terrains.
Features:
Aggressive tread for traction in loose conditions.
Thicker sidewalls for durability.
Load Index: Lower than HT tyres but built for rugged use.
Tip: If you’re mostly on paved roads, HT tyres are your go-to. But if you love exploring trails, MT tyres are worth the noise and reduced efficiency.
Why Tyre Markings Matter
Safety: Mismatched or aged tyres can lead to accidents.
Performance: Correct tyres improve braking, cornering, and fuel efficiency.
Longevity: Tyres chosen for the right terrain and load last longer.
FAQs About Tyre Markings
How Do I Know If My Tyres Are Too Old?
Check the DOT code. Tyres older than 5–6 years, even unused, should be replaced.
Can I Mix HT and MT Tyres?
No. Mixing tyre types can impact handling and safety. Use the same type on all wheels.
How Often Should I Check Tyre Markings?
Inspect tyres every 6 months for wear, cracks, and pressure.
Checklist for Buying Tyres
Verify Size: Match the tyre size to your car’s requirements.
Check Load Index: Ensure it supports your vehicle’s weight.
Inspect the DOT Code: Buy tyres less than 6 months old.
Choose the Right Type: HT for highways, MT for off-road adventures.
Final Thoughts
Tyre markings aren’t just numbers—they’re your guide to safer, smarter driving. By understanding what they mean, you can make informed choices, prolong tyre life, and ensure top-notch performance for every journey.
Have you checked your tyres lately? Drop a comment below or share this post with someone who could use this guide!
