Hitch Ball Sizes and Ball Mounts: How to Choose the Right Setup
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The hitch ball and ball mount connect your receiver to the trailer. Getting three measurements right — ball size, shank size and drop — is the difference between a trailer that tows level and one that sways or scrapes.
1. Match the ball to the coupler
The ball diameter must match the trailer coupler exactly. The size is stamped on the coupler.
| Ball diameter | Typically used for |
|---|---|
| 1-7/8" | Light utility trailers and small boat trailers |
| 2" | Most mid-weight utility, boat and camping trailers |
| 2-5/16" | Heavier trailers and gooseneck hitches |
| 3" | Heavy-duty commercial applications |
A ball that's too small for the coupler can pop off. Check the weight rating stamped on the ball — balls of the same diameter come in different ratings. Browse hitch balls.
2. Match the shank to the ball mount
The ball's threaded shank must fit the hole in the ball mount. Common shank diameters are 3/4", 1" and 1-1/4". A shank that's too small for the hole will loosen. Tighten the ball nut to the torque the manufacturer specifies.
3. Measure drop or rise
The trailer should sit level when coupled. To find the ball mount you need:
- Park the tow vehicle and trailer on level ground. Load the vehicle as you normally would for towing.
- Measure from the ground to the top of the inside of the receiver opening.
- Level the trailer and measure from the ground to the bottom of the coupler.
- Subtract the coupler height from the receiver height. A positive number is the drop you need; a negative number means you need rise.
Lifted trucks often need a large drop; lowered cars may need rise. If you tow several trailers at different heights, an adjustable ball mount saves swapping. Browse ball mounts.
Ratings still apply
The ball mount has its own gross trailer weight and tongue weight ratings. Your setup is limited by the lowest-rated part — see hitch classes explained and tongue weight explained.