What Is C3 Bearing Clearance?
C3 clearance indicates a bearing manufactured with greater-than-normal internal radial clearance. The clearance classes from smallest to largest are: C2 < CN (Normal) < C3 < C4 < C5. Internal clearance is the total distance the inner ring can move relative to the outer ring in the radial direction before mounting.
Why C3 Is Common in the UAE
In the UAE, ambient temperatures frequently exceed 45C, and bearing operating temperatures can reach 80-120C. Thermal expansion of the inner ring reduces internal clearance. C3 bearings start with extra clearance to ensure adequate residual clearance at operating temperature. See the Bearing Installation Guide for clearance verification procedures.
Frequently Asked Questions
When should I use C3 clearance bearings?
Use C3 when: (1) the inner ring has a tight interference fit that reduces clearance, (2) the bearing operates at elevated temperatures (>70C) causing thermal expansion, (3) the bearing is mounted on an adapter sleeve, or (4) the manufacturer specifies C3 for the application. In the UAE's hot climate, C3 is often the default choice.