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AUTO PUNDITZ
Team Auto Punditz

Tyres: The Unsung Heroes of the Road

Updated: Aug 6


The Ultimate Guide to Choosing the Best Tyres for Your Vehicle How often do we cast an admiring look on our vehicles but tend to gloss over one of the most critical components - the tyres? While we take our vehicles for regular servicing, tyres often get a raw deal.


Tyres, being the only point of contact with the road, certainly deserve better attention. In fact, tyres make the critical difference between a safe, fuel-efficient, and enjoyable ride or an unsafe, tiring, and environmentally harmful one.


Over the years, the road profile in India has changed beyond recognition. Thanks to innovations in technology, today we have much more powerful and faster vehicles. We have expressways that allow much higher speeds for much longer distances.


With the change in road and speed profiles, tyre care has assumed all the more importance. Well-maintained tyres will ensure thousands of kilometers of safe journey.

Regular tyre maintenance not only ensures your safety but also contributes to fuel efficiency and reduces environmental impact.


Here are a few key points to keep in mind:


1. Regular Inspections: Check your tyre pressure, tread depth, and overall condition regularly. Underinflated or worn-out tyres can affect your vehicle's handling and fuel efficiency.






2. Proper Inflation: Maintain the recommended tyre pressure as per your vehicle manufacturer's guidelines. Correct tyre pressure ensures better fuel

economy and longer tyre life.





3. Wheel Alignment and Balancing: Ensure your wheels are properly aligned and balanced to prevent uneven wear and tear on your tyres.











4. Rotate Tyres: Regularly rotate your tyres to ensure even wear across all four tyres, extending their lifespan.








5. Choose Quality Tyres: Invest in good quality tyres that are suitable for your driving conditions. Quality tyres offer better grip, handling, and safety.


Taking care of your tyres is not just about prolonging their life; it's about ensuring your safety and the safety of others on the road



Know Your Tyre: What's Inside?


Tyres are not merely black, round objects of moulded rubber; they are sophisticated products of high technology designed to offer a high degree of comfort, performance, ride quality, handling, fuel efficiency, and safety. Understanding the components and markings of a tyre can help you make informed decisions about your vehicle's tyres. Here’s an in-depth look at what's inside a tyre and the essential information found on tyre markings.


Components of a Tyre

Tread

 The tread is the pattern of grooves on the surface of the tyre that comes in contact with the road. Most new tyres have about 8mm of tread pattern when manufactured. The tread pattern is crucial for traction, especially in wet or slippery conditions, and affects the tyre’s noise level and ride comfort.

 

 Tread Wear Indicators (TWI)

 

Every tyre has Tread Wear Indicators (TWIs), which are projections within the tread grooves designed to give a visual indication of the degree of wear. These indicators help you determine when it’s time to replace your tyres. Tyres worn beyond the TWIs are unsafe to drive. There are marks on the shoulder region of a tyre that point to the location of the TWIs.


Aspect Ratio


The aspect ratio is the section height of the tyre as a percentage of the section width. It indicates the tyre’s profile.





Section Width

The section width is the width of the tyre measured in millimetres from sidewall to sidewall.












Construction

Most modern tyres are radial, denoted by the letter 'R' in the tyre markings.












Rim Diameter

The rim diameter is the internal diameter of the tyre, measured in inches.














Decoding Tyre Numbers and Symbols: What Do They Mean?



When you look at the sidewall of a tyre, you'll see a series of numbers and letters that may seem like a secret code. Understanding these markings is essential for ensuring you choose the right tyres for your vehicle. Let's break down what these numbers and symbols mean:


Tyre Size:


This string of numbers and letters, such as "255/55 R16," indicates the size of the tyre. Here's what each part means:


255 – Tyre Width: Indicates the width of the tyre in millimetres from sidewall to sidewall.

55 – Aspect Ratio: Expresses the height of the tyre sidewall as a percentage of the tyre width.

R – Tyre Construction: Indicates the tyre is of radial construction, which is most common today.

16 – Wheel Diameter: Signifies the size of the wheel rim in inches that the tyre is intended to be fitted to.


Load Index and Tyre Load-Carrying Capacity (TLCC)


The load index is a numerical code associated with the maximum load a tyre can carry at the speed indicated by its speed symbol under specified service conditions.


The table below illustrates the relationship between the load index and the tyre load-carrying capacity in kilograms:

Load Index

TLCC (kg)

Load Index

TLCC (kg)

Load Index

TLCC (kg)

Load Index

TLCC (kg)

60

250

76

400

92

630

108

1000

61

257

77

412

93

650

109

1030

62

265

78

425

94

670

110

1060

63

272

79

437

95

690

111

1090

64

280

80

450

96

710

112

1120

65

290

81

462

97

730

113

1150

66

300

82

475

98

750

114

1180

67

307

83

487

99

775

115

1215

68

315

84

500

100

800

116

1250

69

325

85

515

101

825

117

1285

70

335

86

530

102

850

118

1320

71

345

87

545

103

875

119

1360

72

355

88

560

104

900

120

1400

73

365

89

580

105

925



74

375

90

600

106

950



75

387

91

615

107

975




Speed Rating

The speed rating of a tyre is denoted by a letter at the end of the tyre code, representing the maximum speed the tyre can safely handle. For instance, a tyre with a 'V' rating can handle speeds up to 240 km/h, while an 'H' rating is suitable for speeds up to 210 km/h. Choosing tyres with the appropriate speed rating for your vehicle is crucial. Here’s a speed rating chart for reference:

Speed Symbol

Maximum Speed (km/h)

Q

160

R

170

S

180

T

190

U

200

H

210

V

240

W

270

Y

300

Understanding these specifications helps ensure the performance, safety, and efficiency of your vehicle. Always consult your vehicle manufacturer’s manual for the recommended tyre specifications.


Tyre Care & Safety


Tyre Inflation/Air Pressure

Maintaining proper tyre inflation is essential for optimal performance, longevity, and fuel efficiency. Incorrect tyre pressure can lead to uneven tread wear and unsafe driving conditions:

  • Under-Inflation: Causes excessive wear on both sides of the tread, poor handling, reduced fuel economy, and rapid edge wear.

  • Proper Inflation: Ensures correct traction, optimal handling, and maximum tyre lifespan.

  • Over-Inflation: Leads to excessive tread wear in the middle, poor grip, insufficient traction, and rapid center wear.

Check tyre pressure weekly with a reliable gauge when the tyres are cold to ensure safety and performance.


Safety Tips:

  • Under-Inflation Risks: Poor handling, reduced fuel economy, and rapid edge wear.

  • Proper Inflation Benefits: Correct traction, optimum handling, and extended tyre life.

  • Over-Inflation Risks: Poor grip, insufficient traction, and rapid center wear.


Maintaining correct tyre pressure is key to ensuring a safe and enjoyable driving experience.


Wheel Alignment & Balancing

Driving over potholes or uneven surfaces can misalign your vehicle’s suspension, leading to uneven tread wear. Misalignment is often noticeable when the vehicle drifts to one side. Additionally, tyre imbalance can cause wobbling at high speeds.

  • Wheel Alignment: Have your alignment checked periodically, especially if you notice uneven tyre wear, pulling, or vibrations. Proper alignment minimizes tyre wear, maximizes driver control, and ensures safer vehicle operation.

  • Tyre Balancing: Ensure your tyres are balanced correctly. Unbalanced tyres can cause vibrations and uneven wear, affecting stability and handling.

Proper wheel alignment and balancing extend tyre life and enhance the driving experience.


Tyre Repair

Adhering to proper repair guidelines is crucial for maintaining safety and performance:

  1. Puncture Size: Do not repair tyres with tread punctures larger than 6mm.

  2. Tread Wear: Avoid repairing tyres worn beyond the tread wear indicators.

  3. Inner Tubes: Never use an inner tube as a substitute for a proper repair in tubeless tyres.

  4. Repairable Area: Only the tread area can be repaired in passenger car tyres. Avoid repairing the shoulder or sidewall areas.


Repair Guidelines:

  • Repairable Area: Only the central tread area is repairable.

  • Do Not Repair: Avoid repairing the shoulder and sidewall areas.

Following these repair guidelines ensures the continued safety and reliability of your tyres.


Tyre Rotation

Regular tyre rotation ensures even wear and extends tyre life. Here are general rotation patterns if specific recommendations are not available:


  • Front-Wheel Drive (FF): Rotate tyres in a forward cross pattern—move the rear tyres to the front on the same side, and the front tyres to the rear on the opposite side. Include the spare tyre by moving it to the rear right position and placing the rear right tyre in the spare position.

  • Rear-Wheel Drive (FR): Rotate tyres in a rearward cross pattern—move the front tyres to the rear on the same side, and the rear tyres to the front on the opposite side. Include the spare tyre as above.

  • Four-Wheel Drive (4WD): Rotate tyres in an X-pattern—move the front left tyre to the rear right position, the front right tyre to the rear left position, and the rear tyres to the front on the opposite sides. Include the spare tyre as above.


Regular rotation enhances performance, safety, and longevity.


Visual Inspection / Tread Depth

Regular visual inspections, especially for tread depth, are crucial for safety:

  • Tread Wear Indicators (TWI): All tyres have TWI at a depth of 1.6 mm, the legal minimum. Replace tyres when they reach this level.

  • Importance of Tread Depth: Worn tyres require longer stopping distances and impair handling, especially in rainy conditions.


Inspection Guidelines:

  • TWI Exposure: Regularly check for exposed TWI.

  • Uneven Tread Wear: Look for signs of uneven wear, which may indicate suspension or steering issues.

  • Damage Check: Inspect for cuts, damages, or bulges. Even minor damage can lead to tyre failure.

Regular inspections and monitoring tread depth maintain safety and performance.


Did You Know?

  • A tyre bears more than 50 times its own weight, with its contact patch being just the size of a postcard!

  • In India, the use of 5 marked tyres is mandatory for safety.

  • Properly inflated tyres can improve fuel economy by up to 10%.

  • Tyres are crucial for racing, braking, and cornering.

  • Tyres combine physics, chemistry, and high engineering to meet diverse requirements.

  • A tyre undergoes over 20 million deformations during its lifetime!

  • Roads made from recycled tyres can reduce surface noise by up to 20%.

  • The natural color of rubber is white; carbon black is added to enhance tyre longevity.


Tyres play a pivotal role in safety and fuel efficiency, accounting for 20-30% of a vehicle’s fuel consumption. Tyre maintenance is essential, involving over 200 materials in their construction.


Tyre Safety: Myth vs. Fact


Myth: Tread wear is not a safety hazard if even and the fabric or wire is not exposed. Fact: Excessive tread wear is a safety hazard, even if the fabric or wire is not yet exposed. The legal minimum tread depth is 1.6 mm.


Myth: If a tyre doesn’t fail after hitting a curb or pothole, it’s undamaged.

Fact: Tyres can sustain hidden damage from such impacts. Always have them checked after such incidents.


Myth: Air pressure should be reduced for high-speed driving.

Fact: For high-speed driving, air pressure should be increased.


Myth: Petrol pump personnel know the correct air pressure for all cars.

Fact: Air pressure should be checked according to the manufacturer's recommendation on the sticker inside the driver's door.


Myth: It’s okay to buy tyres without an ISI mark if they appear in good condition. Fact: Tyres in India must have an ISI mark to be considered safe.


Myth: Tyres should be replaced only when worn out.

Fact: Replace tyres that are too old or have developed cracks, even if they are not yet worn out.


Myth: Alignment and balancing should be done only as per manufacturer recommendations or replacement dealer.

Fact: Alignment should be checked if pulling or uneven wear is noticed; balancing should be done if vibrations are felt.


Myth: Misalignment only affects tyre wear.

Fact: Misalignment can cause vehicle pulling, leading to driver fatigue and potential accidents.


Myth: Tyres remain the same despite advancements in auto technology.

Fact: Tyre technology has evolved significantly, improving performance, safety, and fuel efficiency.


Myth: There are no regulations for tyres in India.

Fact: Indian regulations include CMVR rules and Quality Control Orders, requiring a minimum tread depth of 1.6 mm and an ISI mark.


Myth: Tyre maintenance is expensive.

Fact: Tyre maintenance is an investment in safety and efficiency. Regular checks and simple measures can enhance performance and extend tyre life.


Happy Motoring


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