Hello Everyone, Welcome to Rajasthan Polytechnic Blogs.
Subject - AUTOMOBILE ENGINEERING ME 40041
Branch - Mechanical Engineering
Semester - 4th Semester
UNIT-V: WHEELS AND TYRES
The wheels and tyres of an automobile play a crucial role in providing support, stability, and traction. Proper maintenance of wheels and tyres ensures safety, better fuel efficiency, and a comfortable ride.
5.1 Wheels
Requirements of a Wheel
A wheel should have the following properties:
-
Strong and durable to support the vehicle’s weight.
-
Lightweight to improve fuel efficiency and handling.
-
Proper balance to avoid vibrations and ensure smooth driving.
-
Good heat dissipation to prevent overheating of brakes.
-
Corrosion-resistant for long life.
Types of Wheels
-
Pressed Steel Disc Wheels
-
Made from stamped and welded steel sheets.
-
Strong, durable, and affordable.
-
Commonly used in passenger cars and commercial vehicles.
-
-
Wire Wheels
-
Made of steel wire spokes connecting the hub and rim.
-
Lightweight and stylish, often used in vintage and sports cars.
-
-
Light Alloy Cast Wheels (Alloy Wheels)
-
Made from aluminum or magnesium alloys.
-
Lighter and stronger than steel wheels, improving performance and fuel efficiency.
-
Used in modern cars and high-performance vehicles.
-
5.2 Tyres
Types of Tyres
-
Tubed Tyres
-
Have an inner tube filled with air between the tyre and rim.
-
If punctured, air escapes rapidly, causing sudden deflation.
-
Used in older cars, bicycles, and heavy vehicles.
-
-
Tubeless Tyres
-
Do not have an inner tube; air is directly sealed within the tyre and rim.
-
Safer and more durable because they deflate slowly when punctured.
-
Common in modern cars and motorcycles.
-
-
Cross Ply Tyres (Bias Ply Tyres)
-
The plies (layers of fabric) are arranged diagonally, overlapping each other.
-
Stronger sidewalls but generate more heat at high speeds.
-
Used in trucks, buses, and off-road vehicles.
-
-
Radial Ply Tyres
-
The plies are arranged radially (at 90° to the direction of travel).
-
Better grip, longer lifespan, and improved fuel efficiency.
-
Common in modern passenger cars and high-performance vehicles.
-
5.3 Tyre Specifications
Tyres are identified using a standard marking system, such as "195/60 R15 88H", which includes:
-
195 → Tyre width in mm.
-
60 → Aspect ratio (height/width percentage).
-
R → Radial construction.
-
15 → Diameter of the wheel (in inches).
-
88 → Load-carrying capacity index.
-
H → Speed rating (maximum speed the tyre can handle).
5.4 Tyre Maintenance
To ensure longevity and safety, tyre maintenance is essential:
-
Regularly check tyre pressure (under-inflated tyres reduce fuel efficiency and over-inflated tyres cause uneven wear).
-
Check tread depth (minimum recommended depth is 1.6 mm for safe grip).
-
Rotate tyres periodically to ensure even wear.
-
Wheel alignment and balancing to avoid uneven wear and vibrations.
5.5 Tyre Troubles and Repairs
Common Tyre Issues
-
Under-inflation → Reduces fuel efficiency, causes overheating, and wears out the edges.
-
Over-inflation → Reduces traction, makes the ride harsh, and wears out the center.
-
Misalignment → Causes uneven wear and affects handling.
-
Punctures and Cuts → Lead to air leakage and require repair or replacement.
Tyre Repairs
-
Puncture Repair → Small punctures can be fixed using rubber plugs or patches.
-
Sidewall Damage → If the sidewall is cut or cracked, the tyre must be replaced.
-
Tread Wear Beyond Limit → Replace the tyre if the tread depth is too low for safety.
Conclusion
-
Wheels provide support and stability, and can be made of steel, wire, or alloys.
-
Tyres come in tubed, tubeless, cross-ply, and radial-ply types, each with specific advantages.
-
Proper maintenance like pressure checks, alignment, and tread monitoring improves performance and longevity.
-
Common tyre issues like under-inflation, punctures, and misalignment should be addressed to ensure safety.
0 Comments