Which Trailer Lock Size Do You Need: 2-Inch vs 2-5/16 Inch?

Which Trailer Lock Size Do You Need: 2-Inch vs 2-5/16 Inch?

When it comes to securing your trailer, choosing the right trailer coupler lock size is just as important as the lock’s build quality. In the U.S., 2-inch and 2-5/16 inch trailer locks are the two most common sizes—but which one is right for you?

In this quick guide, we’ll break down the differences, common use cases, and how to choose the best trailer lock for your setup.

🔍 Understanding Trailer Coupler Sizes

Your trailer’s coupler size is determined by the diameter of the hitch ball it’s designed to latch onto. The most common sizes in the U.S. are:

• 2-Inch Coupler: Often found on light-duty trailers such as small utility trailers, boat trailers, and some travel trailers.

• 2-5/16 Inch Coupler: Common on heavy-duty trailers like car haulers, RVs, and equipment trailers.

🔐 Why Size Matters for Trailer Locks

A trailer lock must fit snugly onto the coupler to effectively prevent theft. Using the wrong size not only reduces security—it might not fit at all.

If you’re using a 2-inch trailer hitch ball, then you’ll need a 2-inch trailer coupler lock that matches precisely. The same applies for 2-5/16 inch couplers, which require a lock designed specifically for that larger diameter.

🚛 Common Trailers That Use 2-Inch Couplers

• Jet ski trailers

• Small boat trailers

• Utility trailers under 5,000 lbs

• Lawn and landscape trailers

✅ Best choice: Jyoelron’s 2-Inch Trailer Coupler Lock – built for light-duty trailers, yet designed with maximum strength and anti-theft features.

🛻 Common Trailers That Use 2-5/16 Inch Couplers

• Enclosed cargo trailers

• Heavy equipment haulers

• RV travel trailers

• Horse trailers

✅ Best choice: Jyoelron’s 2-5/16 Inch Heavy-Duty Trailer Lock – engineered for high-GTW trailers and enhanced trailer security.

🛠️ How to Measure Your Coupler Size

Not sure what size coupler your trailer has? Look for:

• Stamped size on the coupler head (e.g., “2” or “2-5/16”)

• Or, measure the inside diameter of the coupler opening

🔒 Final Thoughts: Get the Right Size, Get Peace of Mind

Choosing the correct trailer lock size—whether 2-inch or 2-5/16 inch—is the first step to real trailer security.

Using a high-quality coupler lock that fits perfectly reduces theft risk and gives you peace of mind when towing or parking your trailer.

💡 Shop our best-selling trailer coupler locks now — available in both 2″ and 2-5/16″ sizes, built to match your exact trailer type.