Why are bikes so inefficient? Unfortunately the problem of drag is fundamental to the motorcycles design, and by "the" I mean just about all motorcycles including the latest, slipperiest sport bikes, which aren't nearly so slippery as you might think, especially when their riders are wearing shorts and tee shirts instead of leathers. Consider for a moment your typical cruiser. The headlight is flat, the mirrors and turn signals stick out like sore thumbs, the rider's legs are splayed and he's sitting bolt upright. If you factor in things like saddlebags and a traditional (maybe not so well designed) windshield the picture is even worse, especially if the rider is wearing loose fitting or bulky riding gear. A motorcycle's wheels are especially problematic. Rotating wheels create an enormous amount of turbulence, especially if they're constructed with spokes, and have exposed brake rotors and calipers, as most motorcycles do. All of those things and more, act to create resistance and disrupt air flow across the bikes surface, so rather than flowing smoothly, the air is turbulent, particularly where it spills off the back of the bike and around the wheels. That creates a lot of drag and unfortunately, overcoming it wastes a lot of power, and fuel.