E39 540ia makes clicking sound over 40mph
 

Hi guys,
I was hoping someone can help me. Recently, my '98 540ia started making this clicking sound once the car gets above 40mph. The sound varies in intensity and speed. sometimes its really loud...other times it's not. It sounds like it's coming from the undercarriage. This sound happens ONLY when the car is moving. If I rev my engine while in park it doesn't make a sound. A few days before this started I had some issues with the front driver side tire. A small piece of the tread came off...exposing the steel belt. The car is still drivable (i'm going to replace that tire soon)...but i was wondering if this has anything to do with that. Maybe it's just a coincidence. I drove the car 4 days with the tire like this before this clicking sound happened...it didn't happen right away.