How to model tank treads? Now, I know the common method of using an array in conjunction with a curve modifier to get the desired result. But, I'm facing some issues. 

(1) The tread segments do not go around the curve completely.

(2) The tread segments get distorted at places.

If I'm not being clear, this is my set up:



Edit: This is a screen shot of the problem. The blue highlight is where the  array is getting distorted. The red highlight is where the array is not following the curve.
Try setting the Relative Offset  Z value to zero.