Tires and Wheels Flashcards

A driver reports that the steering wheel shimmies (oscillates side to side) at around 45–55 mph but is smooth at other speeds. What is the most likely cause?

Answer: Static or dynamic wheel imbalance

Speed-specific shimmy at a narrow speed range is a textbook symptom of wheel imbalance, which creates a resonance at the wheel's natural frequency within that speed band.

After replacing a front tire, a technician performs a wheel alignment check. Which alignment angle, if incorrect, would most directly cause rapid tire wear on the inner edge only?

Answer: Camber

Camber is the angle of wheel tilt; excessive negative camber places disproportionate load on the inner edge of the tire, causing accelerated inner wear.

A vehicle's tires are properly inflated and the tread depth is adequate, but the driver reports poor wet-weather traction. What tire-related fault should be inspected first?

Answer: Hardened or glazed tread compound from age or heat cycling

Aged or heat-cycled rubber loses its elasticity and softness, reducing the tire's ability to conform to the road and channel water, significantly impairing wet traction.

What would happen if a vehicle is driven with mismatched tires — one radial and one bias-ply — on the same axle?

Answer: Unpredictable handling and uneven cornering forces due to different flex characteristics

Radial and bias-ply tires have fundamentally different sidewall and tread flex characteristics, which creates mismatched cornering forces on the same axle, leading to unpredictable and dangerous handling.

During a wheel inspection, a technician notices that several lug nuts on a wheel are loose. What is the most serious risk if the vehicle is driven in this condition?

Answer: The wheel can detach from the vehicle while in motion

Loose lug nuts allow the wheel to wobble and eventually shear the studs, causing complete wheel separation — a potentially fatal hazard at any speed.

A driver notices the vehicle drifts to the right on a level road, but the tires appear to be at equal pressure. After ruling out brake drag, what tire condition should be checked next?

Answer: Tire conicity — a manufacturing defect causing the tire to act like a cone

Tire conicity is a manufacturing defect where the belt layers are off-center, causing the tire to generate a side force in one direction even on a flat road.

What is the correct procedure when installing a tire on a split-rim (multi-piece) wheel to prevent a dangerous blowout during inflation?

Answer: Place the assembled wheel in a safety cage or restraining device before inflating

Multi-piece wheels can explosively separate during inflation if not properly assembled; a safety cage contains the components if separation occurs, protecting the technician.