Pulled a hub bearing off a friend's BMW with 115K miles on it and we were test spinning it to see if it was rough. It was pretty smooth, but we were surprised at how much drag a used bearing had and we pondered why. I surmise the bearing is built with interference or assembled with the balls loaded to keep any play out. If not that it is the grease type being intended for high temps and feels draggy at room temp. I doubt if used seals add that much drag.
Hub bearings design
- Thread starter ledslinger
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Typically roller bearings rather than ball bearings. You need to spin it fast with a drill or something to be able to hear a "bearing noise". By hand is not fast enough.
I think many of the sealed bearing unit type are double row ball bearings.
Typically, 4X4 trucks use double row tapered roller bearings, while cars use double row ball bearings. A good bearing, whether new or used, will have resistance. A worn bearing will spin freely.
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