Bar & Mount Diagram

The ball mount raises or lowers the hitch ball to ensure that your tow vehicle and trailer remain level as you travel. Correct ball mounts will match shaft size to receiver tube dimensions.


  1. Park your vehicle and trailer on level ground.
  2. Level out the trailer tongue.
  3. Measure the TOP of the draw bar shank to the ground for (A).
  4. Measure the BOTTOM of the trailer tongue to the ground for (B).
  5. Subtract B from A for the amount of "drop" you will need to keep your trailer level. A - B = "drop" ("rise" if negative)


A Ball Mount is a removable hitch ball platform that slides into the receiver of a hitch and fastens with a pin and clip. Different ball mounts can be used to raise or lower the height of the ball to allow for level trailer towing.

Identify receiver tube size.

  • Class I & II - 1 1/4" receiver tube
  • Class III & IV - 2" receiver tube
  • Class V - 2" or 2 1/2" receiver tube

Identify mounting location, hitch ball, shank diameter, and thickness. (if not purchasing a combo)

  • Measure the diameter of the hole and thickness of the mounting location to choose a matching ball mount.


A Hitch Ball is the ball-shaped attachment that connects the trailer to a hitch. While the diameter of the hitch ball is fairly standard, shank diameters and hitch ball weight ratings may differ. The rating of the hitch ball is just as important as the receiver hitch ratings.

Ball Diameter (A):

Check the top of the trailer coupler for the size of the ball diameter required. The size is usually stamped there. Recreational and light commercial hitch balls come in a variety of sizes including 1 7/8", 2", 2 5/16" and occasionaly 3". In general lighter trailers use smaller hitch balls. It is VERY important to match the trailer to the correct hitch ball.

Shank Diameter (B):

This is the diameter of the threaded shaft that is inserted through the ball mount. Shanks come in a variety of sizes (5/8", 3/4", 1", and 1 1/4") and capacities. (7,000lbs-17,000lbs)

Shank Length (C):

This is length of shaft that extends beyond the mounting base of the hitch ball. It is important to use a shank that is long enough to extend beyond the thickness of the draw bar mounting tab to ensure that enough threads are available to securely fasten the ball to the mount.

Shank Rise (D):

The height of the shank can be used to raise a trailer back to level in the event the "rise" or "drop" of a ball mount is inadequate.

BUY IT NOW® ©2001- 2019  AutoZone, Inc. All Rights Reserved.