Diagnosed and fixed Highway Humming
After many years of feeding off of this site for tips, tricks, and solutions, I figured it was time to share an experience. Forgive me if this is obvious information, but I had struggled to find an exact answer when trying to diagnose the issue.
Vehicle: 2006 325XI E90 w/ 95,000KM
Symptoms: When driving 80km/h to 130km/h I would experience a loud, pitchy hum. The pitch increased with speed and was not related to the speed of the engine. No screeching or shaking on turns. Sound appeared to be coming from rear of vehicle
Diagnosis: Rear wheel bearing.
Repair: Removed and replaced wheel bearing - 1 day job.
Hope this may help someone in a similar situation.