Radial vs. Axial Load: Bearing Selection Guide with Real-World Applications

Understanding the direction and nature of the loads a bearing must withstand is critical in engineering design and component selection. Two primary forces act on bearings—radial load and axial load—each requiring specific bearing types and configurations. Selecting the wrong bearing for a load type can result in accelerated wear, system inefficiencies, or catastrophic failure.

Whether you’re troubleshooting failure points, designing custom machinery, or optimizing bearing performance, this guide will help you understand how radial and axial loads behave and how to manage them effectively.

Understanding Radial Loads

What Is a Radial Load?

A radial load acts perpendicularly to the shaft’s axis. In simple terms, it pushes or pulls at a right angle to the rotation of the bearing. These forces occur in most rotating machinery where weight, tension, or centrifugal forces are involved.

How Radial Load Transfers Through a Bearing

Radial forces are distributed across the bearing’s rolling elements (balls or rollers) from the inner race to the outer race. Load distribution depends on bearing geometry, clearance, and speed. Even distribution is critical to avoid overloading specific rolling elements.

Typical Applications of Radial Load:

• Vehicle wheels

• Electric motors

• Gearboxes and machine shafts

• Conveyor rollers

• Pulleys and spindles

Bearing Types Best Suited for Radial Loads:

• Deep Groove Ball Bearings – For moderate radial loads and versatility

• Cylindrical Roller Bearings – For high radial capacity and rigidity

• Needle Roller Bearings – For compact designs and high load in small spaces

• Self-Aligning Ball Bearings – Handle radial load with slight misalignment

Understanding Axial Loads

What Is an Axial Load?

An axial load (also known as a thrust load) acts parallel to the shaft’s axis, pushing or pulling along the length of the rotating component. These loads commonly arise in vertical shafts or where components resist axial displacement.

How Axial Load Transfers Through a Bearing

In axial-load-bearing types, force is transmitted through specially designed raceways and rolling elements that align with the shaft’s axis. Some bearings, like tapered roller bearings, manage both radial and axial forces through inclined contact angles.

Typical Applications of Axial Load:

• Vertical drive shafts

• Pumps and compressors

• Screw drives and actuators

• Jet engines and wind turbines

• Automotive clutches and axles

Bearing Types Best Suited for Axial Loads:

• Thrust Ball Bearings – Handle light axial loads at low speeds

• Thrust Roller Bearings – For heavier axial loads

• Angular Contact Ball Bearings – For combined axial and radial loads

• Tapered Roller Bearings – For high-load applications in both directions

Comparison: Radial Load vs. Axial Load

Understanding this distinction ensures correct bearing choice and system design integrity.

Combined Loads in Real-World Systems

In many applications, bearings experience both radial and axial forces simultaneously—known as combined loads. Examples include:

• Automotive wheel hubs – Carry vehicle weight (radial) and turning forces (axial)

• Industrial gearboxes – Transfer torque with axial thrust

• Wind turbines – Handle complex aerodynamic forces in multiple directions

For such systems, the ideal solution is a bearing that balances both types of loads:

• Angular Contact Ball Bearings

• Tapered Roller Bearings

• Spherical Roller Bearings

Careful selection based on load direction, magnitude, and duty cycle is critical.

How Load Type Affects Bearing Life

Misjudging load direction or magnitude can cause:

• Uneven load distribution

• Premature fatigue failure

• Overheating

• Lubrication breakdown

For instance:

• Deep groove ball bearings excel in mostly radial scenarios but tolerate light axial load.

• Angular contact bearings are ideal where high combined loads are expected.

Always match bearing capability to application requirements.

Practical Considerations for Engineers

When selecting bearings based on load:

• Assess operating speed, load direction, and load magnitude

• Consider mounting method, shaft alignment, and housing rigidity

• Choose materials wisely:

  • Chrome Steel (52100): High hardness and fatigue strength

  • Stainless Steel: Corrosion resistance in harsh environments

For example, automotive wheel bearings must support radial (vehicle weight) and axial (cornering forces) loads. In this case, double-row angular contact or tapered roller bearings are standard due to their dual-load capacity.

Choosing the Right Bearing for Your Load

Correctly identifying and managing radial and axial loads ensures:

• Longer bearing service life

• Reduced downtime

• Lower maintenance costs

• Improved machine efficiency