Originally Posted by
wphamilton
I think it speaks the same thing as "I'd rather have a little play than too tight with no play", but try to get in between those two.
It is far from that. From the graph it is visible that no play part give shorter lifetime. As well as wheel that... well - has play.
It is just important not to overdo the preload - but that is not hard - just stop tightening as soon as all the play is gone. There is a margin - as you can tell from the graph.
One thing that isn't shown in the graph: for cup and cone bearings, leaving play will result in pitting on the cones (at least), which is more bother to source and more expensive to replace (than just balls). Making it tight just enough to eliminate play allows for hubs to last for decades - just replace balls from time to time.