Weird sound from motor!

[Jet82388]

So recently I started hearing a weird sound from my rear hub motor. It only makes the sound at 15 mph. Has anyone ever dealt with this? Any help is appreciated.

 

[J.R.]

So recently I started hearing a weird sound from my rear hub motor. It only makes the sound at 15 mph. Has anyone ever dealt with this? Any help is appreciated.

There is a vast wealth of knowledge here, and most people want to help, but more detail is required. What bike? Motor? What is meant by "weird sound"? Any and all information will aid in getting help.