Does the shackle flip cause the rear axle to move forward any? Since you are only lowering the rear end of the spring shouldn't this cause it to move downward on an arch thus pushing the axle slightly forward? Is this the reason for the invention of the zero rates? Also, I can't find the zero rates on the web site - did I miss them somewhere? Just curious, I'm going to be starting a new project and would like to eliminate my rear block. Thanks!!