Here Are Some Technical Facts About Wheels and Tyres!

Most passenger car tires indeed have built-in tread wear indicators. These indicators are small rubber bars that are located in the grooves of the tire's tread. As the tire wears down, these bars become more visible. When the bars are level with the tread, it indicates that the tire has reached its recommended wear limit and needs to be replaced. These indicators help drivers easily determine when their tires are no longer safe for use and need to be changed.

Tightening lug nuts beyond specifications can cause excessive pressure on the brake rotor, leading to distortion. This can occur because the rotor is not designed to withstand the excessive force applied by overtightened lug nuts. As a result, the rotor may become warped or uneven, affecting the overall performance and safety of the braking system. Therefore, it is important to adhere to the recommended specifications when tightening lug nuts to prevent damage to the brake rotor.

The correct answer is "On the tire placard" because the tire placard is a sticker or label usually located on the driver's side door jamb or inside the fuel filler door. It provides important information about the car's tires, such as the recommended tire size, recommended tire pressure, and the maximum load capacity. This information is crucial for maintaining the safety and performance of the vehicle, so it is important to refer to the tire placard for accurate tire information.

An over-inflated tire shows wear in the center of the tread because when a tire is over-inflated, the center of the tread bears the majority of the weight and therefore wears down faster than the outside edges. This can lead to uneven tire wear and reduced traction on the road.

The size designation of P205/70R14 indicates that the tire has a width of 205 mm. The distance between the rim and the top of the tire is given as 70 percent of this width, which is 70 percent of 205 mm. Therefore, the correct answer is 70 percent of 205 mm.

The statement is false because vehicles with run-flat tires are actually equipped with tire pressure monitoring systems. Run-flat tires are designed to allow a vehicle to continue driving even after a tire has lost air pressure. In order to ensure the safety and performance of the run-flat tires, tire pressure monitoring systems are necessary to alert the driver if there is a loss of air pressure in any of the tires. These systems help to prevent accidents and maintain the optimal performance of the run-flat tires.

All of the above belt materials are commonly used in radial tires. Steel, nylon, and fiberglass are all commonly used materials for the belts in radial tires. These materials provide strength, durability, and flexibility to the tire, allowing it to maintain its shape and support the weight of the vehicle. Nylon and rayon are also commonly used in the construction of radial tires, providing additional strength and stability. Therefore, all of the options listed contain materials that are commonly used in radial tires.

Technician A is correct. An incorrect tire and wheel size can indeed affect bearing life. When the tire and wheel size is not properly matched to the vehicle's specifications, it can lead to increased stress on the bearings, causing them to wear out faster. On the other hand, Technician B is incorrect in stating that changing tire and wheel sizes does not affect antilock brake systems. Changing the tire and wheel sizes can affect the overall diameter of the wheel, which can impact the accuracy of the ABS system's speed sensors.

Both Technician A and Technician B are correct. Tire sidewall markings typically include information such as maximum load, traction, wear ratings, maximum inflation pressure, tread plies, and sidewall plies. These markings are important for ensuring that the tire is used within its recommended limits and for providing information about its performance characteristics. Therefore, both technicians are correct in their statements about the information indicated by tire sidewall markings.

The statement is false because when replacing tires, it is recommended to renew the valve stems regardless of whether they are leaking or not. Valve stems can become worn or damaged over time, leading to potential air leaks or tire pressure issues. Therefore, it is best to replace them along with the tires to ensure optimal performance and safety.

The profile of a tire refers to the aspect ratio of the tire's sidewall height to its width. It is an important characteristic that affects the tire's performance, including its handling, stability, and ride comfort. The profile is usually indicated by a number in the tire's size designation, such as 65 in a tire size of 205/65R15, where 65 represents a 65% aspect ratio. Therefore, the profile is another name for a tire's aspect ratio or sidewall height.

Wheel balancing is not only required when new tires are installed but also when there is an imbalance in the tire, which can cause vibrations and uneven wear. It is a regular maintenance procedure that ensures a smooth and comfortable ride.

Both Technician A and Technician B are correct. Sealer injected through the valve stem can indeed damage tire pressure monitoring sensors. The chemicals in the sealer can corrode the sensors, leading to malfunction or failure. Additionally, sealer injected through the valve stem can be flammable. If the sealer comes into contact with a source of ignition, it can catch fire, posing a safety risk. Therefore, both technicians are correct in their statements about the potential risks associated with injecting sealer through the valve stem.

Technician A is correct. E.M.T. (run flat) tires can incorporate an inner support ring. This inner support ring provides additional support to the tire, allowing it to continue running even when it is punctured or loses air pressure. Technician B is incorrect in stating that E.M.T. tires do not incorporate reinforced sidewalls.

Both technicians are incorrect. Tire traction ratings are indicated by letters such as AA, A, B, or C, while tire temperature ratings are indicated by letters such as A, B, or C. Therefore, neither Technician A nor Technician B is correct.