A customer dropped off a Racing Zero Carbon (high-end racing bike) for me to work on.


The wheel centering was nearly perfect and the runout was minimal,
but both the front and rear hubs had play in them, so I tightened them up.
The front hub especially—if I'd left it alone, it probably would've developed bearing damage pretty quickly.


Also, the right end nut—which uses a reverse thread—had loosened by hand.