The bite number corresponds with your cross weight percentage. If you look at your cross number, it is below 50%. The -18 is the amount of weight you are shy on the RF and LR from being at 50% cross. If you were running cross weight at over 50%, that bite number would be a positive (+) number. I wouldn't pay too much attention to the bite number. Just worry about your percentages...Left, Rear, and Cross. Where do you race?