Hitches, Receivers & Ball Mounts
Trailer Hitch Ball Sizes
The coupler decides the ball, not the mount and not the truck. Getting this wrong is how trailers come off.
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Short answer
Three sizes cover almost everything: 1-7/8 in for light trailers, 2 in for most mid-size trailers, and 2-5/16 in for heavy ones. The size is stamped on your trailer's coupler, and it is not a preference.
Identify yours in ten seconds
Look at the top of the coupler on the trailer's A-frame. The size is stamped or cast there, often alongside a capacity rating. If it is painted over, a tape measure across the inside of the coupler throat gets you close enough to identify which of the three it is.
| Diameter | Typical use | Notes |
|---|---|---|
| 1-7/8 in | Small utility, light boat, pop-up | Lowest capacities; easily confused with 2 in by eye |
| 2 in | Most mid-size trailers, campers, car haulers | The most common size by a wide margin |
| 2-5/16 in | Heavy travel trailers, equipment, large boats | Higher capacity on the same mount |
Shank size is a separate specification
Below the ball is the threaded shank, which has its own diameter and length. The shank diameter must match the hole in your ball mount, and the length must be adequate for the mount's thickness plus the nut and washer. CURT's 2 in stainless ball, for example, is published on a 1 in shank 2-1/8 in long with a 6,000 lb capacity.
Torque is a real number
That same CURT ball publishes a 250 ft-lb mounting torque. That is far beyond what anyone achieves with a crescent wrench and a tug, and it is the specification that gets ignored most often. An under-torqued ball nut works loose, and a ball that works loose is a failure in progress. If you do not own a torque wrench that reaches that figure, a mount sold with the ball already fitted removes the problem.
Quick picks
Tap any row to jump to the full write-up. How these are chosen - and what we do and do not claim to know - is published in full on our research methodology page.
| # | Product | Best for | Our read | Price |
|---|---|---|---|---|
| 1 |  CURT 2 in Stainless Trailer Ball (1 in shank, 6,000 lb) Common replacement | Replacing a worn or wrong-size ball | 2 in, 6,000 lb, 250 ft-lb torque | Check price on Amazon #ad Affiliate link - we publish no price; Amazon shows the current one |
| 2 |  CURT Adjustable Channel Mount with Dual Ball (2 in shank, 6 in drop) Two sizes at once | Garages with several trailers | 2 in and 2-5/16 in on one mount | Check price on Amazon #ad Affiliate link - we publish no price; Amazon shows the current one |
| 3 |  CURT Loaded Ball Mount with 2 in Ball (2 in drop, 7,500 lb) Ball already fitted | One trailer at a known height | Removes the torque step entirely | Check price on Amazon #ad Affiliate link - we publish no price; Amazon shows the current one |
1. Common replacement
CURT 2 in Stainless Trailer Ball (1 in shank, 6,000 lb)
CURT · Best for replacing a worn or wrong-size ball
A replacement 2 in ball on a 1 in shank, rated to 6,000 lb, with a published torque figure of 250 ft-lb. That torque number is the reason to buy a ball from a manufacturer that publishes specs: an under-torqued ball nut is a genuine failure mode.
Published specifications
What works
- Published torque specification, which many balls do not come with
- Stainless finish survives a boat ramp better than plain zinc
- Correct shank sizing is spelled out rather than assumed
What does not
- 6,000 lb ceiling is below what many 2 in couplers are rated to carry
- Needs a torque wrench to fit properly, which many people do not own
Skip it if
Not enough ball if your coupler is rated above 6,000 lb - match the ball to the coupler's rating, not to the hole in your mount.
#ad Affiliate link - we publish no price; Amazon shows the current one
Raw specifications: CURT’s own page. We earn nothing on that link.
2. Two sizes at once
CURT Adjustable Channel Mount with Dual Ball (2 in shank, 6 in drop)
CURT · Best for garages with several trailers
One mount that covers two ball sizes and a range of heights, which is the answer when the garage contains a boat trailer, a utility trailer and a camper that all sit at different heights. Capacity drops to the lower-rated ball you are actually using.
Published specifications
What works
- Two ball sizes and a height range in a single mount
- Flipping it gives rise as well as drop
- Rated to 14,000 lb on the larger ball
What does not
- Heavy, and more joints means more places for rattle to start
- The pins and bolts need checking for torque, unlike a one-piece mount
Skip it if
Pointless if you own one trailer and tow it with one truck - a fixed mount at the right height is lighter, quieter and cheaper.
#ad Affiliate link - we publish no price; Amazon shows the current one
Raw specifications: CURT’s own page. We earn nothing on that link.
3. Ball already fitted
CURT Loaded Ball Mount with 2 in Ball (2 in drop, 7,500 lb)
CURT · Best for one trailer at a known height
A one-piece mount with the ball already fitted and torqued, rated to 7,500 lb gross and 750 lb tongue with a 2 in drop. Nothing adjusts, which is exactly why nothing rattles or works loose.
Published specifications
What works
- Arrives with the ball fitted, so there is no torque step to get wrong
- One piece means nothing to loosen or rattle
- Light enough to leave in the receiver or throw in a toolbox
What does not
- The 2 in drop is the only drop - measure before you buy
- 7,500 lb ceiling rules out heavier trailers
Skip it if
Useless on a lifted truck, where a 2 in drop will still leave the trailer nose-high and the weight on the rear axle of the trailer.
#ad Affiliate link - we publish no price; Amazon shows the current one
Raw specifications: CURT’s own page. We earn nothing on that link.
Key takeaways
- The coupler stamp decides the ball size. Nothing else does.
- A smaller ball in a larger coupler can latch and still come off.
- Shank diameter and length are separate specifications from ball diameter.
- Mounting torque is a published figure in the hundreds of ft-lb, not hand-tight.
How we sourced this
Every figure on this page came from one of the following, each fetched while the page was written. Where a manufacturer or regulator does not publish a number, we say so rather than estimate it.
Common questions
- Can I use a 2 in ball on a 2-5/16 in coupler?
- No. It will not latch properly and the connection is not rated. Match the stamp on the coupler exactly.
- How do I know if my ball is worn?
- Look for flat spots, scoring and a measurable reduction in diameter at the contact band. A worn ball increases play, which both rattles and lets the coupler move more than it should.
- Do I need to grease the ball?
- Yes, for a conventional coupler - it reduces wear on both parts. The exception is any friction surface that provides sway control, which must stay dry.
More in Hitches, Receivers & Ball Mounts
Class, receiver size, ball diameter, drop. Four numbers decide whether your setup is right, and three of them are stamped on parts you already own.
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Guide
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Reference
Hitch Classes Explained
The class system from 1 to 5, the two ratings on every label, and the mistake of inferring capacity from tube size.
How to
How to Hook Up a Trailer
The full hitching sequence, why chains cross, where the breakaway cable goes, and what to check before you move.
Found something out of date, or a figure you can source better than we did? Corrections get read first. How we research explains how these pages are put together, and contact is one click away.