At a glance
Expansion / floating
Allows shaft growth through an internal displacement feature or a specified sliding fit.
Use at the position assigned to accommodate calculated shaft-to-housing thermal movement.
Non-expansion / locating
Holds the shaft at the required axial reference position.
Use where the assembly must carry the specified axial forces and establish shaft location.
Key differences
Typical design distinctions. The complete designation and current product specification take precedence.
Swipe the table horizontally to see both options →
| What to compare | Expansion / floating | Non-expansion / locating |
|---|---|---|
| Axial role | Allows designed movement | Provides axial location |
| Thermal growth | Receives the required displacement | Defines the reference end |
| Mechanism | Internal movement or sliding ring/housing interface | Retaining rings, shoulders or other locating features |
| Available travel | Must exceed required operating movement | Not intended to absorb growth by sliding |
| Load check | Confirm radial support during displacement | Confirm axial as well as radial capability |
| Failure risk | Travel can be blocked by incorrect assembly | Two unintended locating positions can create thermal thrust |
Before you choose
- Do not loosen mounting bolts to create an expansion bearing.
- The expansion distance and direction belong to the exact housing and bearing design.
- Account for differential growth of both shaft and housing.
Check the actual model
Search a full designation, inspect its technical data, then compare candidate records. Similar names or dimensions do not guarantee interchangeability.
Filters show recorded catalogue attributes. Open each candidate to confirm its exact specification.
A few things worth clarifying
Does expansion mean the bearing material stretches?
The term normally describes axial movement permitted by the arrangement.
Should every pair have one floating end?
Many arrangements do, but matched or adjusted systems can use another engineered method. Follow the assembly design.
Reference basis & limits
- SKF — Cylindrical roller bearings: NU, NJ and NUP designs, publication 13085
- Timken — Mounted Tapered Roller Bearing Catalog: expansion and non-expansion units
Independent explanatory content; not a manufacturer endorsement or approval of a replacement. Verify current product data, fits, lubrication and operating conditions before applying a comparison.