« Back to Dictionary Index
Turning Circle
The turning circle, also known as the turning radius or turning diameter, refers to the smallest circular path that a vehicle can take when making a full turn with the steering wheel at full lock (maximum steering angle). It is an important measure of a vehicle’s maneuverability.
Key Points:
- Turning Radius vs. Turning Diameter:
- Turning Radius: The distance from the center of the turning circle to the outer edge of the vehicle’s path. It is often measured in feet or meters.
- Turning Diameter: The diameter of the full circle the vehicle describes. It is twice the turning radius and is also commonly measured in feet or meters.
- Factors Influencing Turning Circle:
- Wheelbase: The distance between the front and rear axles. Vehicles with a shorter wheelbase typically have a smaller turning circle.
- Steering Angle: The maximum angle at which the front wheels can be turned. A greater steering angle reduces the turning circle.
- Vehicle Width and Length: The physical dimensions of the vehicle can influence the space required to complete a turn.
- Steering Mechanism: The design and type of steering system (e.g., rack and pinion, recirculating ball) can affect the turning circle.
- Tire Size and Type: The size and grip of the tires can impact the vehicle’s turning capability.
- Practical Implications:
- Urban Driving: A smaller turning circle is advantageous for maneuvering in tight spaces, such as parking lots, narrow streets, and city driving.
- Off-Road Capability: For off-road vehicles, a smaller turning circle enhances the ability to navigate through rough terrain and obstacles.
- Large Vehicles: Trucks, buses, and other large vehicles typically have larger turning circles, making them less maneuverable in confined spaces.
Measurement of Turning Circle:
- Curb-to-Curb: This measurement considers the outer edge of the tires’ path while making a turn, typically when the front wheels are at full lock.
- Wall-to-Wall: This measurement includes the vehicle’s extremities, such as mirrors and bumpers, providing a more comprehensive assessment of the space needed for a turn.
Examples:
- Compact Cars: Generally have a turning circle ranging from 9 to 12 meters (30 to 40 feet).
- Sedans: Typically have a turning circle between 10 to 12 meters (33 to 40 feet).
- SUVs and Trucks: Can have a turning circle ranging from 12 to 15 meters (40 to 50 feet) or more, depending on size and design.
Applications:
- Vehicle Design: Engineers consider the turning circle during the design phase to ensure the vehicle meets the intended use and market requirements.
- Driver Convenience: Knowledge of a vehicle’s turning circle helps drivers make informed decisions about parking, maneuvering in tight spaces, and overall vehicle handling.
The turning circle is a critical parameter that defines a vehicle’s ability to navigate tight turns and confined spaces. It is influenced by various factors, including wheelbase, steering angle, and vehicle dimensions, and has practical implications for everyday driving and vehicle design.
See
- Turning radius.