How to Measure the Size of a Hitch Ball

by David Thompson
camping,trailer image by Greg Pickens from

Hitch balls connecting trailers to vehicles come in three standard diameters. To make sure a ball fits, you also need to measure its shank diameter and length. Larger balls with larger-diameter shanks can pull more weight. Manufacturers divide hitches into different classes, but in general, 1 7/8-inch-diameter balls with smaller shanks can pull up to 2,000 lbs. Two-inch balls may be rated for pulling up to 3,500 or 5,000 lbs. depending on the shank size. Choose a hitch rated for the amount of weight you plan to pull that matches the size of the trailer's coupler.

Step 1

Hold a ruler horizontally on top of the hitch ball and sight down directly from above. Align the first mark of the ruler with the widest part of the ball on one side and note where the other side of the ball is aligned. The ball should measure either 1 7/8, 2, or 2 5/16 inches.

Step 2

Lay the threaded part of the ball's shank on the ruler and sight down to measure the shank's diameter. The shank is the bolt-like shaft that extends below the ball. Its diameter will probably be 5/8, 3/4, 1, 1 1/4 or 1 3/8 inch.

Measure the length of the shank, starting just below the wide base supporting the ball and measuring to the end. The length doesn't affect towing capacity, but it needs to be long enough to fit your mounting platform.