Y'all make good points, but I just find that hard to believe... seems like they would be in the way allot... I still think I am going to have to ride allot (and possibly find someone w/ them that will let me ride their bike to see what they are like) before I decide that I want/need them.
Thanks for the good info though.

 

Nerf bars are required for MX racing. During the holeshot of a motocross race. Many quads are running side by side around the first corner. If one machine should slide into the other. That racer's nerf bars will stop the wheel from the sliding quad from coming in and hitting his leg. Also, it stops from hooking tires with another racer causing one of the quads to "ride up" the wheels of the other. Possibly flipping a quad.
Woods racers use nerf bars to slide around trees. In off-chamber and slick-muddy hills, where it is hard to maintain a strait line. Nerfs help you scoot along the trees. They also prevent you from catching the rear axle on a tree. Saving possible damage.