I have a portable speaker and just used 2 bungee cords and it worked fine. because the jbl extreme already has mounts on it for carrying strap and feet on the bottom just use a bungee cord. having said that, you would be better served with a speaker that has directional sound where the speakers are in the front. the jbl extreme is a round speaker and i think you'll find that a lot of the sound is being directed away from you (360). because you are on a bike and surrounded by other sounds, you really need a speaker where you can direct the sound at your face. i'm sure it will be fine if you keep the mph under 50 but at highway you will prob struggle to hear it.How can I mount a jbl extreme 2 to my 03 fatboy handle bars. Any ideas? Anyone.