Actually, that's not quite correct.
If the traction bar is mounted in front of the axle, it will also want the axle to travel along the radius described by the bar length, pivoting at the forward mount. Problem is, the arcs are not exactly the same so you will get some bind. To minimize the bind, the length of the anti-wrap bar should be slightly less than the length of the spring from front eye center line to axle center line. This is due to the arc distortion due to the spring flattening making the effective radius of the axle arc smaller than it might seem.