Self-lubricating bearings are widely used in dry-running applications where external lubrication is not feasible. However, different materials behave very differently under these conditions.

Among the most common options, PTFE-based bearings, fiber-reinforced bearings, and metal-backed composite bearings show significant differences in friction, wear resistance, load capacity, and thermal performance.

Understanding PTFE vs fiber vs metal-backed bearings in dry running is essential for engineers and procurement professionals when selecting the right material for performance, reliability, and cost.

PTFE vs Fiber vs Metal-Backed Bearings in Dry Running: Key Differences

The following table provides a quick comparison of the three material types under dry-running conditions:

This comparison highlights how dry running bearing materials differ in performance depending on operating conditions.

Material Behavior in Dry Running Conditions

PTFE Bearings

• Form a transfer film that provides very low friction

• Perform well in light-load and precision applications

• Sensitive to high load and high temperature

Fiber-Reinforced Bearings

• Use reinforced structure to improve wear resistance

• More stable under dry friction conditions

• Suitable for continuous operation with moderate to high load

Metal-Backed Composite Bearings

• Combine a metal support layer with a low-friction sliding layer

• Offer higher mechanical strength and heat dissipation

• Perform well in heavy load and demanding environments

PV Limits and Operating Conditions

In dry-running applications, PV value (Pressure × Velocity) is a critical parameter for evaluating material performance.

• PTFE bearings → lower PV tolerance, sensitive to overheating

• Fiber bearings → improved PV resistance due to reinforcement

• Metal-backed bearings → higher PV capacity with better heat dissipation

Exceeding PV limits may lead to increased wear, thermal damage, and reduced service life.

Temperature and Thermal Stability

Dry-running conditions generate more heat due to the absence of lubrication, making thermal performance critical.

• PTFE materials offer low friction but limited high-temperature resistance

• Fiber materials provide better stability under continuous heat exposure

• Metal-backed structures improve heat dissipation and reduce thermal stress

Common Failure Modes in Dry Running Bearings

Each material type shows different failure behavior under improper conditions:

• PTFE bearings → transfer film breakdown, thermal softening

• Fiber bearings → abrasive wear, surface fatigue

• Metal-backed bearings → sliding layer delamination, fatigue under load

These failure modes are typically related to excessive load, unstable operating conditions, or poor heat control.

Which Material Should You Choose?

Choosing between PTFE vs fiber vs metal-backed bearings depends on application priorities:

• Choose PTFE bearings → when low friction and smooth motion are the top priorities

• Choose fiber-reinforced bearings → when wear resistance and stability under dry friction are critical

• Choose metal-backed bearings → when high load capacity and durability are required

In many cases, the best solution involves balancing friction, load, temperature, and expected service life.

Application Comparison

• PTFE bearings → precision equipment, light-load systems

• Fiber bearings → industrial dry-running environments, continuous operation

• Metal-backed bearings → heavy machinery, shock load, high-load systems

Procurement Considerations for Dry Running Bearing Materials

Material selection alone does not determine performance. Manufacturing quality and consistency also play a key role.

• Consistency of composite material formulation

• Quality control of sliding layer

• Performance validation under dry-running conditions

• Supplier experience with similar applications

Reliable supplier capability helps ensure consistent performance across different batches and applications.

Conclusion

PTFE, fiber-reinforced, and metal-backed bearings each offer distinct advantages under dry-running conditions. Their differences in friction, wear resistance, load capacity, and thermal behavior make them suitable for different applications.

By comparing these materials based on operating conditions and performance requirements, engineers and procurement teams can make more informed and reliable selection decisions.

For a deeper understanding of how dry-running conditions affect bearing behavior, see why self-lubricating bearings perform differently under dry-running conditions.