[MCahoon]

I'm afraid I don't recall who posted it, but there was a thread in which a "NASCAR" chassis set up was discussed (maybe M Krass recalls it). I believe it was based on a 6 wheel chassis, with the front pair of wheels slightly larger than the center pair of wheels which were in turn slightly larger than the rear set. I believe the concept was that since two of the three pairs would tend to be slipping, that they would tend to be able to move sideways somewhat easier (think of a rear drive car. when the drive wheels are spinning, the rear of the car is very easy to push sideways). It may be that a 4-wheel drive system with the front and rear running on different sprocket sizes would be somewhat easier to turn . I would agree that it would essentially be only a little better than a 2-wheel drive system in terms of pushing power.