[Vu2000]

We've tried using 1 motor on each side to get 4 wheel drive, and we've never had a successful drive train. What we used was the drill motor in the middle, and had a long chain running from the front sprocket to the back sprocket and tensioners on both sides of the drill motor.

The problem with that is: since your not running the chain from front to rear, you don't have enough wrap around your sprocket. An ideal drive train probably has around 140-150 degrees of wrap. Because our drive train did not have enough wrap, the sprocket and chain would engage well and the sprocket would always slip when we drive, and it would make that weird buckling noise because of the slippage.

We have since tried 2 wheel drive and it works better than before... next year we'll go back two 4 wheel drive but maybe this time with a double sprocket or 4 motors?