Which Hitch Ball Does Your Trailer Dolly Need? Coupler Size, 1-Inch Shank and Rating

Short answer: the hitch ball on your trailer dolly needs to match three things. Its diameter has to match your trailer's coupler, its shank has to be 1 inch so it fits the Trailer-Tug 3.0 or Monster-Tug mount, and its weight rating should be suited to the trailer it's holding.

Neither dolly ships with a ball, and powersports owners with more than one trailer may find their couplers don't share a size.

1. Ball diameter: let the coupler decide

The coupler is the socket on the trailer tongue that drops over the ball. According to towing-safety manufacturer Weigh Safe, most trailer manufacturers stamp or label the correct ball size on the coupler, and if the marking is missing you can measure the coupler's inside opening to find it. The same guide says a trailer needs a ball that matches the size of its coupler.

Sizes you're likely to see stamped on a coupler:

• 2 inch – Weigh Safe calls this the most common hitch ball size.
• 2-5/16 inch – listed by Weigh Safe, along with 2 inch, as a size used to tow most travel trailers.
• 1-7/8 inch – a smaller size that some couplers call for.

Example (hypothetical): two trailers, two stamps

Say you keep a single-axle open trailer for two ATVs and an enclosed trailer for a side-by-side. The first coupler is stamped 2 in; the second reads 2-5/16 in. One ball can't serve both, so you'd swap balls on the dolly between trailers, tightening each one to its maker's instructions.

2. The 1-inch shank: the dolly's one hard requirement

The shank is the threaded stem under the ball that passes through the mount and is held with a nut. The Trailer-Tug 3.0 and Monster-Tug listings both say the dolly works with any hitch ball that has a 1-inch shank. So the diameter on top is your trailer's requirement, and the shank underneath is the dolly's.

A spare ball from the garage may have the right diameter but a different shank. Check both numbers on the ball or its packaging before assuming it will fit, and make sure there's enough thread for the nut to fully engage. If you're unsure, measure and ask us before your first move.

Our 2" Hitch Ball has a 2-inch ball, a 1-inch shank and a 2-3/4-inch shank length. We also carry a 2-5/16-inch ball with the same 1-inch shank, but it's out of stock right now. If your coupler calls for 2-5/16, our ball listings note the dollies work with any ball size as long as the shank is 1 inch.

3. Weight rating: read the stamp on the ball too

Ball diameters are standard, but load ratings aren't. Weigh Safe notes that ratings differ from ball to ball and says a tow ball's rating must match or exceed the trailer's GVWR (gross vehicle weight rating). Holding the ball on your dolly to that same towing standard keeps the ball from being the weak link.

Keep the dolly's own rating separate in your head. Trailer-Tug 3.0 is rated for up to 3,500 lbs of tongue weight and Monster-Tug for up to 1,200 lbs. That's tongue weight, not the trailer's total weight. If you haven't measured yours, our tongue weight explainer covers three ways to do it. A rating also isn't a measure of effort: a loaded trailer can be within capacity and still take two or more people to move, especially with tandem axles or soft ground.

4. A fit check before your first move

• Read the coupler stamp and the ball stamp. The diameters must match.
• Confirm the shank is 1 inch and the nut is tightened to the ball maker's instructions. Our accessories guide covers how the ball and Stabilizer fit together.
• On level ground, lower the coupler over the ball and confirm the latch closes fully, with the pin or lock in place if your coupler uses one.
• Recheck the ball rating against the heaviest load you'll put on that trailer, not just its empty weight.

For the full hook-up and unhook order (chocks, tongue jack and hold brakes), follow our step-by-step hook-up guide.

Which dolly fits a powersports trailer?

The ball rules are identical for both. What differs is the ground and the tongue weight.

• Trailer-Tug 3.0: built for hard surfaces like concrete and asphalt, such as a garage floor, paved driveway or shop slab. Rated up to 3,500 lbs of tongue weight.
• Monster-Tug: 13x6.50-6 in flat-free polyurethane wheels for gravel, dirt, grass and uneven ground. Rated up to 1,200 lbs of tongue weight, and the listing advises helpers on trailers over 6,000 lbs. A loaded toy hauler can exceed that tongue rating, so measure first.

Our surface guide goes deeper on that choice. Whichever you use, move on level ground only; never take a manual dolly up or down an incline. The hold brakes keep a stopped trailer in place but aren't designed to stop a rolling one, so chock the wheels once you're parked.

Ready to set yours up?

If your coupler is stamped 2 inch, the 2" Hitch Ball is ready to go on either dolly. If it's a different size, or you're not sure a ball you already own will fit, contact us with the coupler stamp and your shank measurement and we'll help you sort it out.