2 5/16" Hitch Balls
Reese recommends that you torque all 3/4" shank balls to 160 ft. lbs, all 1" to 250 ft. lbs., and 1 1/4" shank balls to 450 ft. lbs.
Always remember to grease your hitch ball when towing.
Class III hitches (2" x 2") under 6,000 lbs use a 1" Shank.
Class III/IV/V hitches (2" x 2" or 2 1/2" x 2 1/2") over 6,000 lbs generally use a 1 1/4" Shank