Pictures would be useful perhaps detailed pictures for the construction of the first vehicle, and then just a picture of the finished vehicle, and maybe what it looks like in the object editor.
I've found that to make wheels turn nicely (without pinching in places), it's best to drive the wheels from as far away as possible. That way, the starting angles are similar for all four points on the wheel.
To make the driven cart out of less objects, you can make the chassis half a square longer in each direction, and drive the wheels from the corner directly above the wheel. Also, you can one wheel from the centre of the other wheel (though this looks messy in the editor).
One last thought: to get a fast vehicle to start properly without tipping, try putting fairly slippy (friction = 0.1) tiles under the back wheel. It starts slightly slower, but is less likely to tip.
I've found that to make wheels turn nicely (without pinching in places), it's best to drive the wheels from as far away as possible. That way, the starting angles are similar for all four points on the wheel.
To make the driven cart out of less objects, you can make the chassis half a square longer in each direction, and drive the wheels from the corner directly above the wheel. Also, you can one wheel from the centre of the other wheel (though this looks messy in the editor).
One last thought: to get a fast vehicle to start properly without tipping, try putting fairly slippy (friction = 0.1) tiles under the back wheel. It starts slightly slower, but is less likely to tip.