The shanks on your ripper look just like the shanks on my Rollover Box Blade, so I have a pretty good idea of the draft force resisting your ripper.
I also have a Dirt Dog Field Cultivator. A Field Cultivator is easier to pull as the points, at the end of parabolic tines, are pulled through the earth almost horizontally.
6/10/2015
Field Cultivators and Chisel Plows have parabolic shaped tines in common. Parabolic tines pull much easier through soil than angled shanks, such as those equipping Box Blades. From my observation, this is because parabolic shaped tines have the forward part of the tines in nearly a horizontal position working the soil. Field Cultivator tines are tipped with sharp, chisel points further reducing draft resistance.
Each sharp chisel point on my Field Cultivator is 2" X 10" = 20 square inches, oriented horizontally. Chisel points are uniform 5/16" thick. Tines are 1/2" wide.
Box Blade shanks are angled at 45 degrees to reach the bottom of road potholes and chip out surrounding hard road surface. They are designed for rigidity to apply bludgeon force. Box Blade points have an edge but get fat immediately.
Each Box Blade ripper point on my Rollover Box Blade is 1-1/4" X 5-1/4" = 6-1/2 square inches, oriented at 45 degrees. Orientation at 45 degrees hugely increases draft resistance. Box Blade shanks are 5/8" wide.
The engaged five tine Field Cultivator pulls easily, relative to my five shank Rollover Box Blade, with shanks down.