The purpose of an anti roll bar is to prevent the body from rolling excessively due to cornering force. When the car body rolls because of cornering, the outer wheels are compressed and the inner wheels are un-compressed. The anti roll bars tries to twist and so transfers the compression forces to the other wheel by pushing it downwards without affecting the suspension motion.
This is a principle I first heard of whilst grass tracking many many years ago.. ARBs are available for most RC cars and fitting one(or two..)may help your driven wheels stay in contact with rough terrain, so they might be a good idea for tracks with bumpy corners.. on bumpy straights an ARB might cause loss of traction as no cornering forces are present..? or maybe im talking cobblers who knows?
