Vehicles are 4 wheel drive by default. You can, however, change that within the script, by doing this:
function GrottiniVehicle::onAdd(%this,%obj)
{
parent::onadd(%this,%obj);
%obj.setWheelTire(0, GrottiniFrontTire);
%obj.setWheelTire(1, GrottiniFrontTire);
%obj.setWheelTire(2, GrottiniTire);
%obj.setWheelTire(3, GrottiniTire);
%obj.setWheelSpring(0, Grottinispring);
%obj.setWheelSpring(1, Grottinispring);
%obj.setWheelSpring(2, Grottinispring);
%obj.setWheelSpring(3, Grottinispring);
%obj.setWheelPowered(0, false );
%obj.setWheelPowered(1, false );
%obj.setWheelPowered(2, true );
%obj.setWheelPowered(3, true );
%obj.setWheelSteering(0,1);
%obj.setWheelSteering(1,1);
%obj.setWheelSteering(2,0);
%obj.setWheelSteering(3,0);
%obj.mountable = true;
}
I've been experimenting with 2WD vehicles for a while, and here are my conclusions:
If you make a car rear wheel drive, turning gets really stiff. Really, really stiff, especially when going backwards. However, with a little modification to the wheel datablocks, you can make a very fun, very slippery car.
If you make a car FWD, steering gets even stiffer when going forward. I haven't put too much research time into FWD cars, though, but I'm sure it could be helped a little by adjusting the wheel datablocks.