Published 2026-10-09 · Ride On Rentals, Delta BC
How to pick the right trailer ball: diameter, shank, height and rating, plus what BC regulations say about the hitch connection and safety chains.
The ball on your hitch is a small part with one job: hold the trailer to the vehicle. It is also the part people most often get wrong when they turn up to collect a trailer. The wrong size, the wrong rating, or a ball mount that tips the trailer nose-down all show up the moment you try to couple. This guide covers trailer ball size from the ground up, what else on the ball and mount matters, and what BC's regulations say about the connection.
CURT, a major hitch manufacturer, explains in its trailer ball size guide that there are four standard diameters. It describes what each is generally used for:
| Ball diameter | Typical use (per CURT) |
|---|---|
| 1-7/8 inch | Light-duty trailers; ratings up to about 2,000 or 3,500 lb depending on the ball |
| 2 inch | The most common size; utility trailers, boat trailers, campers; ratings from 3,500 to 12,000 lb |
| 2-5/16 inch | Heavier trailers; most weight-distribution hitches; some balls rated up to 30,000 lb |
| 3 inch | Gooseneck trailers |
The ratings in that table are ranges across many products. The only rating that applies to you is the one stamped on your own ball.
Match the ball diameter to the trailer's coupler. The four standard sizes are 1-7/8, 2, 2-5/16 and 3 inches, and most manufacturers stamp the correct ball size on the coupler. The 2-inch ball is the most common and, according to CURT, the best fit for most Class 3 hitches. The coupler is the cup on the front of the trailer tongue that drops over the ball.
No. CURT warns that a ball and coupler of different sizes can create an unsafe towing situation that may lead to the trailer disconnecting. A 2-inch ball can sit inside a 2-5/16-inch coupler and feel latched while still being able to pop out over a bump. That is the classic mismatch, and it is why we ask what you tow with when you book.
Look at the top of the ball. The diameter is usually stamped there along with the weight rating. If the stamp has worn off, measure across the widest part of the ball with a tape measure or ruler. While you are looking, check the ball isn't loose on the mount, the nut is tight, and there are no deep gouges or flat spots.
A trailer ball has four measurements: ball diameter, shank diameter, shank length and rise. The shank is the threaded stem that bolts through the ball mount platform. CURT's guidance: "If the trailer ball shank is too small, it will shift while towing and likely come loose." If the shank is smaller than the hole, a reducer bushing may make up the difference.
The ball mount itself is the bar that slides into your hitch receiver. Its shank has to match the receiver opening, and it has its own capacity rating. Our guide to hitch classes covers receivers and classes. This guide stays on the ball end.
A ball of the right diameter at the wrong height is still a problem. CURT's ball mount guide is blunt: "When towing, your vehicle and trailer must be level."
Lifted trucks often need a mount with a big drop. Lowered cars and some crossovers need rise. CURT notes that many mounts can be flipped for rise, but "not all models can safely be used in the rise position", so check yours.
A nose-down trailer puts extra weight on the hitch and can unload the vehicle's front axle. A nose-up trailer moves weight behind the axle. ICBC's towing guide links too little hitch weight to sway and too much to steering problems. A level trailer is the starting point for getting that balance right.
Yes. Your setup is only as strong as its weakest part: the receiver, the ball mount, the ball and the coupler each carry their own rating. CURT notes the ball capacity reflects gross trailer weight, and you must choose a ball whose capacity exceeds the gross weight of the trailer.
BC's CVSE branch says the same thing in regulatory language. Its Trailer Towing info sheet says hitch hardware "must be of adequate size and capacity" for the trailer, and that "hitches are usually stamped with their capacity." The trailer's own maximum is set by "the weakest component, whether that is the tires, axles, brakes, hitch, or other equipment."
So read four stamps before a heavy haul: receiver, ball mount, ball and coupler. Use the lowest number. Then check it against your vehicle's tow rating in the owner's manual. See can my SUV tow a rental trailer? for that side.
Section 7.07 of the Motor Vehicle Act Regulations sets out the coupling rules. No one may drive a vehicle and trailer on a highway unless:
The same section prohibits towing a trailer that "whips or swerves unreasonably or otherwise fails substantially to follow the path of the towing vehicle". That links back to a level, correctly loaded trailer.
BC's Motor Vehicle Act Regulations require an auxiliary coupling device, such as chains, with a breaking strength not less than the gross weight of the trailer. ICBC's towing guide recommends crossing the chains under the ball and hitch, so the tongue is caught if the coupler lets go. Leave enough slack for tight turns, but not so much that the chains drag on the road.
Do this at home the day before, not in our yard:
Most of our trailers tow behind a standard truck or SUV with a Class 3 hitch. Tell us your vehicle when you book and we will confirm compatibility and any hitch or wiring needs. Then run through the towing checklist when you collect it. Browse all trailer rentals or call (604) 767-7977.
Match the ball diameter to the trailer's coupler. The four standard sizes are 1-7/8, 2, 2-5/16 and 3 inches, and most manufacturers stamp the correct ball size on the coupler. The 2-inch ball is the most common and, according to CURT, the best fit for most Class 3 hitches.
Look at the top of the ball. The diameter is usually stamped there along with the weight rating. If the stamp has worn off, measure across the widest part of the ball with a tape measure or ruler.
No. CURT warns that a ball and coupler of different sizes can create an unsafe towing situation that may lead to the trailer disconnecting. A 2-inch ball can sit inside a 2-5/16-inch coupler and feel latched while still being able to pop out over a bump.
Yes. Your setup is only as strong as its weakest part: the receiver, the ball mount, the ball and the coupler each carry their own rating. CURT notes the ball capacity reflects gross trailer weight, and you must choose a ball whose capacity exceeds the gross weight of the trailer.
BC's Motor Vehicle Act Regulations require an auxiliary coupling device, such as chains, with a breaking strength not less than the gross weight of the trailer. ICBC's towing guide recommends crossing the chains under the ball and hitch, so the tongue is caught if the coupler lets go.
Questions about a rental trailer? Call Ride On Rentals at (604) 767-7977 or email [email protected].