independant 4 wheel drive

[ahecht]

The past few years, we have used a small adjustable sprocket both as an idler to assure 180 degrees of wrap on all driven or driving sprocket, and as a chain tensioner. It works quite well.

You can see a picture of our 2k3 design here (this picture was taken during repairs, so there is slack in the chain). The bolt on the right hand side of the trapeziodal piece is what moves the idler up and down, and the sprocket at the bottom is connected to the motor. The is a stationary idler on the other side near the wheel that isn't quite visible.

Also, by placing the idlers above the driven sprocket on one side and below the driven sprocket on the other side, we could have both our motors running the same direction (which is much more efficient than the worm gear solution posted above, since worm gear efficiency is around 70% at best, while sprocket efficiency is around 97%).