I have an 8 speed with 3.21 gears, 305/55/20 Falkens Wild Peaks at 72 lbs a piece, 2.8 Bils, 1.5 rear coil spacers, 2.5 inch wheel spacers, putting my tires in the wind, and it pulls my 21 foot ski boat around with no problems at all. Actually, it does a great job! I can still get over 20 mpg...