How do you know if a bearing is tight enough on a sleeve?

To determine if a bearing is tight enough on a sleeve, observing “slight drag on the bearing” is important because it indicates the proper fit between the bearing and the shaft or sleeve. When there is a slight drag, it means that the bearing is adequately seated and has the necessary interference fit, which allows it to operate efficiently without excessive play.

This slight drag ensures that the bearing can handle the loads it will encounter during operation while preventing potential slippage or movement that could lead to premature wear or failure. Additionally, this condition allows the bearing to rotate, while still maintaining a close tolerance that is essential for optimal performance and longevity.

In contrast, a pre-load condition refers more specifically to an intentional force applied to the bearing to eliminate end play, rather than a measure of fit. "Bottoms out" suggests that the bearing is pressed completely against the end of the sleeve, which can lead to unwanted stress and should be avoided. Finally, a loose sleeve would indicate an improper fit, increasing the likelihood of vibration, misalignment, and damage to both the bearing and the associated components.