Just go it from tilling and brought the book in this time, but Rat beat me to it. It is quite simple just follow the directions and you will know how fast you are going. After doing mine I knew when I was tilling at 2.4 MPH, before setting mine when I thought I was doing 2.0, the actual speed was about 3.6 so who knows what the factory was set for, not for R-1's for sure.