What Part of a Car Turns the Wheels?

The steering system turns the wheels left and right, while the drivetrain turns them rotationally to move the car. In everyday terms, the steering wheel and its linkages change direction, and the engine or motor—through the transmission, differential, and axle shafts—spins the wheels. Understanding both systems clarifies how a car points and goes.

Two Ways Wheels “Turn”

Drivers often mean two different actions when they say “turn the wheels.” One is changing the wheel angle to steer the vehicle; the other is spinning the wheels to propel the vehicle forward or backward. These two actions are handled by distinct systems that work together.

The Steering System: What Points the Wheels

The steering system translates driver input at the steering wheel into a change in the front wheels’ angle (and, in some vehicles, rear-wheel steering at low or high speeds). Modern cars typically use rack-and-pinion steering with electric power assist.

Key components that turn the wheels left or right include:

• Steering wheel and steering column: Transmit the driver’s input.
• Steering gear (rack-and-pinion or recirculating-ball): Converts rotational input into lateral movement.
• Tie rods (inner and outer): Link the rack to the steering knuckle on each wheel.
• Steering knuckle: Pivots the wheel assembly about ball joints.
• Power assist: Electric power steering (EPS) or hydraulic assist reduces effort.

Together, these parts pivot the wheel assemblies so the car changes direction. Without them, the wheels would still spin, but you couldn’t steer.

The Drivetrain/Powertrain: What Spins the Wheels

The drivetrain delivers torque that makes the wheels rotate. In internal-combustion vehicles, the engine’s output passes through the transmission and driveline; in electric vehicles, one or more motors supply torque directly to an axle or hub.

Core components that rotate the wheels include:

• Engine or electric motor: The torque source.
• Transmission (or reduction gear in EVs): Sets torque/speed for the road.
• Driveshaft/prop shaft: Carries torque to a distant axle (in RWD/AWD layouts).
• Differential: Splits torque left-right and allows different wheel speeds in turns.
• Axle shafts/CV shafts: Send torque from the differential to each wheel.
• Wheel hub and bearings: Support the wheel and allow smooth rotation.

These components make the wheels spin under power. Without them, you could steer, but the car wouldn’t move on its own.

The Differential’s Critical Role

The differential both changes the direction of torque (from the driveshaft to the axle shafts) and allows the left and right wheels to rotate at different speeds, which is essential while cornering.

Common differential types include:

• Open differential: Standard; simplest and smoothest, but can spin away torque on low-traction surfaces.
• Limited-slip differential (LSD): Restricts speed difference to improve traction.
• Locking differential: Mechanically locks wheels together for maximum off-road traction.
• Electronic torque vectoring: Uses clutches or brakes to actively apportion torque.

The chosen differential type affects traction, handling, and performance, especially in slippery conditions or spirited driving.

Common Drivetrain Layouts

Where the driven components sit—and which wheels are powered—varies by vehicle design. This affects weight balance, packaging, and traction.

Typical layouts include:

• Front-wheel drive (FWD): Engine/transaxle drives the front wheels via short CV shafts.
• Rear-wheel drive (RWD): Engine up front, transmission and driveshaft to a rear differential and axle shafts.
• All-wheel drive (AWD)/4WD: Torque to both axles via a transfer case or power take-off; may include a center differential or clutch pack.

Each layout changes how torque is delivered and which wheels do the work, but all still rely on a differential and axle shafts to spin the wheels.

Wheel-End Parts That Make It Possible

The rotating and steering functions meet at the wheel-end assembly, allowing both pivoting for steering and smooth rotation for motion.

Important wheel-end components include:

• Wheel hub and bearing unit: Supports the vehicle’s load and allows low-friction rotation.
• Steering knuckle/upright: Mounts the hub and connects to suspension and tie rods.
• Ball joints: Act as pivots for steering and suspension movement.
• CV joints (on driven, independent suspensions): Allow torque transfer through steering angles and suspension travel.

These parts ensure the wheel can both pivot for steering and rotate smoothly for propulsion without binding.

EV-Specific Considerations

Electric vehicles simplify some elements but keep the same fundamentals: something must steer the wheels, and something must spin them.

Typical EV configurations include:

• Single motor, single axle: One motor drives either the front or rear axle via a reduction gear and differential.
• Dual motor, AWD: One motor per axle; software manages torque split.
• In-wheel (hub) motors: Less common; motor inside each wheel eliminates traditional axles but adds unsprung mass.

Regardless of configuration, EVs still use steering racks, tie rods, knuckles, hubs, and bearings to point and rotate the wheels reliably.

Signs of Trouble in Systems That Turn the Wheels

Wear or faults in steering or drivetrain components can compromise safety and drivability. Early detection helps prevent costly failures.

Watch for these symptoms:

• Steering pull, play, or wander: Possible tie-rod, rack, or alignment issues.
• Groaning or heavy steering: Power assist (EPS/hydraulic) faults or low fluid (hydraulic systems).
• Clicking on turns: Likely worn CV joints on FWD/AWD vehicles.
• Howling or rumbling with speed: Wheel bearing wear.
• Vibration under acceleration: Axle shaft imbalance or U-joint issues.
• Wheel hop or traction loss: Differential, tire, or suspension problems.

If these symptoms appear, have the vehicle inspected promptly to maintain safe steering and dependable propulsion.

Summary

The steering system—steering wheel, column, rack-and-pinion, tie rods, and knuckles—turns the wheels left and right to guide the car. The drivetrain—engine or motor, transmission, differential, and axle shafts—turns the wheels rotationally to move the car. Together, these systems ensure the vehicle points where you want and gets there under power.

What makes the wheels turn on a car?

The system of engine, crankshaft, transmission, drive shaft, transfer case, and axle all work together to turn the wheels. If any part of that system doesn’t work properly, the wheels will not move. The wheels and tires attach to the vehicle with lug nuts and bolts and stop with disc brakes.

How are car wheels turned?

You might be surprised to learn that when you turn your car, your front wheels are not pointing in the same direction. For a car to turn smoothly, each wheel must follow a different circle. Since the inside wheel is following a circle with a smaller radius, it is actually making a tighter turn than the outside wheel.

What spins the wheels of a car?

In a car, the engine applies the force to the axle which rotates the wheels and moves the vehicle forward.

What part of the car turns the wheels?

In most cars, small trucks and SUVs on the road today, there is a rack and pinion steering system. This converts the rotational motion of the steering wheel into the linear motion that turns the wheels and guides your path. The system involves a circular gear (the steering pinion) which locks teeth on a bar (the rack).