Internal Circlips Explained: What They Are and Where They're Used
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Internal circlips may be small, but they play a vital role in countless automotive, engineering and industrial applications.
Designed to fit inside a bore or housing, internal circlips provide a simple and effective way to retain bearings, bushes, seals and other components without the need for threads, adhesives or complex fasteners.
In this guide, we'll explain what internal circlips are, how they work, and where they're commonly used.
What Is an Internal Circlip?
An internal circlip is a spring steel retaining ring designed to fit into a machined groove inside a bore.
Once installed, the circlip expands into the groove and prevents components from moving axially within the housing.
Unlike external circlips, which fit around a shaft, internal circlips are fitted inside a hole or housing.
They are typically installed using circlip pliers that engage with the small holes at either end of the ring.
How Do Internal Circlips Work?
Internal circlips rely on spring tension.
When compressed using circlip pliers:
- the circlip diameter reduces
- it can be inserted into the bore
- it then expands into the groove
Once seated correctly, the circlip acts as a positive stop, preventing movement of the retained component.
This provides a secure retention method while allowing relatively quick assembly and disassembly.
Common Uses for Internal Circlips
Internal circlips are found throughout automotive, industrial and engineering equipment.
Typical applications include:
Bearings
One of the most common uses.
Internal circlips are frequently used to retain bearings within:
- gearboxes
- electric motors
- pumps
- wheel hubs
Oil Seals
Many housings use internal circlips to retain oil seals in position.
This prevents movement under vibration and pressure changes.
Bushes and Sleeves
Internal circlips are often used to locate:
- bushes
- sleeves
- spacers
within machined housings.
Automotive Components
Examples include:
- transmissions
- differentials
- steering systems
- wheel bearing assemblies
where compact and reliable retention is required.
Why Use Internal Circlips?
Internal circlips offer several advantages:
Compact Design
No threads, nuts or bolts required.
Cost Effective
Simple components that provide reliable retention.
Easy Maintenance
Components can often be removed and replaced quickly using circlip pliers.
Reliable Retention
Suitable for vibration-prone environments such as vehicles and machinery.
Internal vs External Circlips
The difference is simple:
| Type | Installed On |
|---|---|
| Internal Circlip | Inside a bore or housing |
| External Circlip | Around a shaft |
Both perform the same basic function but are designed for different installation locations.
Choosing the Correct Internal Circlip
The correct circlip is determined by:
- bore diameter
- groove dimensions
- material specification
Using the correct size is essential to ensure proper seating and retention.
A circlip that is too small or too large may not fully engage with the groove and can lead to premature failure.
Internal Circlips at Seal With Selo
We're expanding the Seal With Selo range to include internal circlips in a wide range of sizes.
Our circlips are manufactured from carbon spring steel and are suitable for many automotive, industrial and engineering applications.
Available from UK stock with no minimum order quantity, they're ideal whether you need one circlip or several.
In Summary
Internal circlips provide a simple, reliable and cost-effective method of retaining components inside housings and bores.
From bearings and oil seals to gearboxes and industrial machinery, they remain one of the most widely used retaining solutions in engineering.