I've seen some 3 wheeled vehicles on battle bots a long time ago, and some 3 wheeled line following robots. They type I am interested in, do not have a steering mechanism. They steer like a tank or a bulldozer or ZTR lawn mower. 2 parallel wheels have independent drive mechanisms and the 3rd wheels is a caster. Turning is accomplished by commanding a higher speed to one drive wheel than the other, or applying brakes to one drive wheel and not the other. they can literally turn on a dime, in place. I have never seen a high speed vehicle that employs this method (have you? links or leads if so, please?). When I picture a vehicle like this operating at high speed, the picture is very cloudy. I don't know how it would behave. I'm looking for examples of this if they exist (I haven't been able to find any) or even just your speculation of how it would behave. Imagine a ZTR lawn mower going 100mph. I picture 2 wheels in front, with one following caster in the rear - would be safer, more stable at high speed and less likely to tip in cornering than a tricycle design. I am guessing, that the longer and narrower the vehicle is, the less likely it would be to make unintentional drastic turns at high speed, but the more difficulty it would have making tight turns at low speed and vise versa. I presume there would be some optimal ratio of length to width. It's unclear to me whether it would be able to turn at all at high speed. This isn't an automotive thread, just a physics curiosity of mine.