Grade 10 power mechanics – Road Wheels Quiz

Road wheels carry the vehicle's weight and provide a rolling surface so the vehicle can move along the road.

The tyre bead is the reinforced edge of the tyre that sits against the rim flange and creates an airtight seal for tubeless tyres.

Tyre codes show width in millimetres, aspect ratio as a percentage of width, and rim diameter in inches (R for radial).

Radial tyres are widely used for passenger cars because they give better grip, fuel economy and ride comfort compared with bias-ply tyres.

Under-inflation increases the tyre's contact area and flexing, causing higher wear, heating and possible tyre failure.

Balancing ensures mass is evenly distributed so wheels do not vibrate, improving comfort and tyre life.

Alignment sets the wheel angles (camber, caster, toe) so tyres contact the road correctly and wear evenly.

Positive camber is when the top of the wheel leans away from the vehicle centreline.

Toe-in refers to wheels pointing slightly toward each other at the front, affecting steering stability and tyre wear.

Regular tyre rotation evens wear among tyres; manufacturers commonly recommend rotation every 8,000–12,000 km.

You must secure the vehicle by setting the parking brake and placing wheel chocks to prevent rolling before jacking and removing a wheel.

A wheel or lug wrench provides the leverage to loosen tight wheel nuts safely before raising the vehicle on a jack.

Wheel bearings are rolling element assemblies that support the wheel and allow smooth rotation with minimal friction.

Tubeless tyres hold air at the bead and often seal small punctures, reducing sudden blowouts and simplifying repairs compared with tube tyres.

Tightening in a criss-cross pattern draws the wheel onto the hub evenly, preventing misalignment or damage to the wheel or brake disc.

Grooves and sipes help move water away from under the tyre so the rubber keeps contact with the road, reducing aquaplaning.

Worn bearings often make a rumbling, humming or grinding noise that varies with road speed and can indicate bearing failure.

Reducing speed, moving to a safe place and warning other road users keeps you safe until you can repair or change the tyre.

Tyre speed ratings are letters that show the maximum speed a tyre is certified to carry a specified load safely.

Bolt pattern and offset affect how the wheel mounts and its position; incorrect fit can cause rubbing, steering issues or unsafe load on bearings.

Tyres below the safe tread depth reduce grip, especially on wet roads, and should be replaced to maintain safety.

Schrader valves are the common, sturdy valve types found on most car tyres and accept standard air pumps and gauges.

Misaligned camber or toe angles make the tyre contact uneven, leading to excessive wear on one edge.

A proper repair combines an internal patch with an external plug and must be done correctly to restore tyre safety; roadside quick fixes are unsafe.

Over-inflation makes the tyre bulge at the centre, reducing grip, making the ride firmer and causing the centre of the tread to wear faster.

Road wheels carry the vehicle’s weight and transfer torque from the axle to the road so the vehicle can move. They are not for storing energy or cooling the engine.

Wheel nuts thread onto studs or bolts to clamp the wheel to the hub. The other parts do different jobs like controlling air or covering the wheel.

Alignment sets the wheel angles so tyres meet the road correctly; it does not change engine or battery parameters.

Balancing adds small weights so the wheel/tyre assembly spins without wobble, reducing vibration and wear. It doesn't affect brakes, tread depth or battery.

If the wheels are misaligned (wrong camber or toe) the tyre edges wear faster. Engine oil, windscreen dirt or headlights do not cause tyre edge wear.

A sidewall bulge means internal cord damage; the tyre can fail suddenly and must be replaced. It cannot be safely repaired or kept in use.

Low pressure increases rolling resistance and sidewall flexing, causing higher fuel use and quicker wear. It usually worsens braking and handling.

Regular tyre rotation (about every 8,000–10,000 km) helps even wear. Waiting for punctures or doing it by time alone is not correct, and it is unrelated to weekly oil changes.

Tubeless tyres form an air-tight seal with the rim and do not use inner tubes. Tubed tyres have a separate inner tube holding the air.

A lug wrench is designed to fit wheel nuts and provide the leverage needed. Screwdrivers and other tools are not suitable for wheel nuts.

Wheel bearings reduce friction between moving parts and carry the vehicle's load while allowing smooth wheel rotation.

A star pattern ensures even seating of the wheel on the hub. Tightening one nut fully first can cause misalignment and uneven clamping.

Tread grooves evacuate water from the contact patch so the tyre keeps grip on wet roads and reduces hydroplaning risk.

Space-saver spares are smaller and rated for temporary use at low speeds and limited distance. They are not a permanent replacement.

Cold tyres give the most accurate pressure reading because heat from driving raises pressure and gives a false high reading.

Imbalance causes oscillating forces that produce vibration, often felt through the steering wheel or floor at certain speeds.

The rim is the wheel's metal part that the tyre seats against; it is not part of the tyre tread or braking system.

Camber is the vertical tilt of the wheel: top leaning in or out. Other answers describe different concepts.

Designated jacking points are reinforced to safely lift the car. Using bumpers, sidewalls or unstable ground can be dangerous.

Loose wheel nuts reduce clamping force and can allow the wheel to detach. They do not affect unrelated systems like radio or lights.

Worn tread cannot channel water effectively, greatly increasing stopping distance on wet surfaces. Rim paint, hubcaps or window cleanliness do not affect tyre grip.

The hub connects the wheel to the vehicle axle and holds the bearings. It does not inflate tyres or change gears.

Directional tyres have arrows indicating the correct rotation direction to ensure proper water evacuation and performance.

Over-inflation makes the tyre more rounded, reducing grip and comfort and causing the centre of the tread to wear faster.

With the tyre touching the ground, final tightening to the correct torque ensures safe clamping. Other actions are irrelevant or unsafe.