How to Position Bearings for Better Fan Performance

How to Position Bearings for Better Fan Performance

Industrial fans and blowers use two types of bearings: a fixed (held) bearing and an expansion (floating) bearing. Where you place these bearings matters. Correct positioning helps extend bearing life and keeps your equipment running longer.

Fixed vs. Expansion Bearings: What’s the Difference?

A fixed bearing holds the shaft in place and controls its position. It keeps the shaft from moving side to side. An expansion bearing allows the shaft to move slightly. This is important because the shaft expands as it heats up. For example, Rex and Link-Belt bearings use locking collars to hold the shaft at the fixed position. Their expansion bearings include features that let the shaft slide without losing support.

Horizontal Shaft Fan Bearing Positioning (Overhung Design)

In a horizontal shaft, overhung fan:

1. Put the fixed bearing closest to the drive system.
2. Place the expansion bearing near the fan wheel housing.

This setup allows the shaft to expand and contract without putting extra stress on the bearings.

Horizontal Shaft Fan Bearings with Center-Mounted Wheel

When the fan wheel sits between two bearings:

1. Install the fixed bearing between the drive system and the fan wheel housing.
2. Place the expansion bearing on the opposite side of the fan wheel, farthest from the drive.

Always match the original layout used by the fan manufacturer whenever possible.

Vertical Shaft Fan Bearing Placement

Note the type of shaft drive system used.

Vertical Shaft Fan Bearing Placement (Belt-Driven Systems)

For vertical shaft fans with a belt drive:

1. Place the fixed bearing closest to the fan wheel housing.
2. Install the expansion bearing near the drive end.

This arrangement helps manage load and shaft movement effectively.

Vertical Shaft Fan Bearings (Direct Drive Systems)

For vertical shaft fans with a direct or coupled drive:

1. Position the fixed bearing closest to the drive end.
2. Place the expansion bearing near the fan wheel housing.

This setup supports the drive system and controls movement at the correct point.

Replacing Bearings: What to Watch For

Before removing old bearings:

• Check and record the exact position of both bearings.
• Do not assume the bearings use the standard layout.

In about 99% of cases, the setups above apply. However, some systems are designed differently. Manufacturers may reverse positions to balance loads based on the fan design.

Need Help With Bearings?

If you're unsure about bearing placement, contact a bearing specialist or refer to the original equipment manufacturer (OEM) documentation.

If you have questions about bearing-related issues, call (317) 273-5781 or email [email protected]. For videos and other demos, visit our YouTube channel.

Page Updated: May 19, 2026