The tire is shorter, lengthens RT by about .01 After dark the bulbs on the tree are brighter and it shortens my physical reaction time. I used to red light a lot 1st round after dark until I did this. Nothing more frustrating than putting yourself in the trailer by going red by -.005 or -.003! Some people use a tinted visor after dark but I've never tried that. Around here if you don't turn consistent .01 lights in no electronics classes you don't win. The guys with electronics always seem to be in the double zeros! Some good tree people around my area.