That is a wheel bearing. Loading the car onto the good side by turning takes weight off the bad bearing and the noise drops, which is how we tell left from right without taking anything apart.
Tyres worn into a saw-tooth pattern make almost the same noise, so we run a hand across the tread first. Bearings do not fix themselves and a collapsed one can take the hub with it.
How we tell: Quieter turning one way than the other at the same speed.
In this order
The same three steps as every car that comes through the door: the check, then the quote, then your old parts.
JMD 3,500comes off the bill
Up on the ramp, every joint and bush levered and listened to.
0JMD 60,000120,000
Whatever comes off your car is bagged with your registration on it and handed to you when you collect. It is the simplest proof that the part we charged you for was the part we changed.