Assuming I know what you are referring to, which would be the fact that the front wheels turn at a larger degree than the second set of wheels, then I can also assume you haven\'t built a multiple steered axle model before.
Read through the \"Steering\" section of this page for a good explanation.
http://www.jenniferclarkbass.com/lego/hooklift.htm
http://www.jenniferclarkbass.com/lego/imag...ng_trig_lrg.gif