Feature

Precision fits: An often-overlooked key to maximising bearing performance

When evaluating bearing performance, material quality and lubrication typically take centre stage – a focus justified by BDS Bearing’s findings that these factors, along with poor fitting, account for up to 70 percent of bearing failure cases. Despite this, the critical role of precision fits – the exact interplay between a bearing’s inner ring and shaft, or its outer ring and housing – is often overshadowed by other considerations.

04/03/2025 12:55:56

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Here, Chris Johnson, Managing Director of SMB Bearings, explores why precision fits demand greater attention from engineers and manufacturers.

At its core, a bearing fit refers to how
tightly or loosely the bearing’s rings mate with their respective components. Fits are classified as interference, clearance or transitions, and each plays a specific role. For instance, an interference
fit secures the bearing in place under heavy loads by creating a tight grip between components, while clearance fits allow slight movement to accommodate thermal expansion or operational
misalignments.

Transition fits strike a balance, offering enough security to hold the bearing in place while enabling easier assembly and maintenance. Precision fits, where tolerances are meticulously controlled, ensure
optimal load distribution and minimise the risks of slippage, wear, or overheating. However, even high-quality bearings can fail prematurely if these fits are misjudged.

Read the full article in DPA's March 2025 issue

Written By Sophia Bell

Sophia Bell is the Group Editor of DPA, Connectivity, and PBSI. She joined the team in 2020 as Assistant Editor after achieving a First-Class Honours BA in English Literature and Film Studies from the University of East Anglia. In her current role, she leads the editorial strategy, driving digital growth and ensuring each title continues to deliver trusted, relevant insight for engineering and manufacturing professionals.