Hitch Basics: Ball Sizes, Receiver Classes, and Weight Distribution

The hitch is the one part that connects everything, so it's worth understanding. Hitches come with a lot of numbers and terms, but once you know what they mean, it's simple to make sure your setup is safe.

The parts of a hitch setup

A typical bumper-pull hitch setup has three main parts:

1. The receiver: the square tube bolted to your vehicle's frame.
2. The ball mount: the piece that slides into the receiver and holds the ball. It's held in with a hitch pin and clip.
3. The hitch ball: the ball that the trailer's coupler sits on.

Each part has its own weight rating. Your setup is only as strong as the lowest-rated part.

Ball sizes

The three most common ball sizes are:

• 1-7/8 inch: for small, light trailers
• 2 inch: very common, for a wide range of utility and landscape trailers
• 2-5/16 inch: for heavier trailers, including many equipment trailers

The ball must match the coupler. Look at the trailer's coupler. The required ball size is usually stamped on it. A ball that's too small can pop out of the coupler on a bump, even if the latch seems closed.

Also check the ball's shank diameter (the threaded part) matches the hole in your ball mount, and that the ball's weight rating, stamped on top, covers your trailer.

Receiver classes

Receivers are grouped into classes. Exact ratings vary by manufacturer, but roughly:

• Class I: light duty, small cars and light trailers
• Class II: a bit more capacity, often with a 1-1/4 inch receiver
• Class III: the most common on pickups and SUVs, with a 2 inch receiver
• Class IV: heavier duty, often also a 2 inch receiver
• Class V: heavy duty, often a 2 or 2-1/2 inch receiver

Always go by the label on your actual hitch, not the class alone. Most hitches list two numbers: the maximum gross trailer weight and the maximum tongue weight. Some also list higher numbers for use with a weight distributing hitch.

Drop, rise, and level towing

The trailer should sit level when hitched. If the trailer's nose points up or down, it changes how weight sits on the axles and how the trailer handles.

Ball mounts come with different amounts of drop (the ball sits lower than the receiver) or rise (higher). To find the right one:

1. Park the trailer on level ground, level it with the jack, and measure from the ground to the bottom of the coupler.
2. Measure from the ground to the top inside of your vehicle's receiver.
3. The difference is about how much drop or rise you need.

Keep in mind your truck will squat a bit under the trailer's tongue weight.

Safety pins and locks

• The hitch pin and clip hold the ball mount in the receiver. Make sure the clip is in place.
• The coupler latch should be closed and secured with a pin or lock.
• The hitch ball nut should be tight. Check it once in a while.

All of these belong on your pre-trip checklist.

What is a weight distributing hitch?

A weight distributing hitch (WDH) is a special hitch setup with spring bars that connect the hitch head to the trailer frame. When tensioned, the bars spread some of the trailer's tongue weight forward to your vehicle's front axle and back to the trailer's axles.

That gives you:

• A more level tow vehicle, without the rear sagging
• Better steering, since the front tires carry their share of the weight
• Better braking
• Headlights that aim where they should

Many weight distributing hitches also include sway control, which helps keep the trailer stable in wind or when trucks pass.

A WDH is a big help for heavier trailers, especially behind half-ton trucks and SUVs. It doesn't replace good loading. Load the trailer correctly first, as we explain in our tongue weight guide, then use the WDH to level the setup.

Both of our rental trailers can have a weight distributing hitch added. Just ask when you book. See the Rental Fleet page for details.

Before you tow

Check that:

• The ball size matches the coupler
• Every part is rated for the loaded trailer weight and tongue weight
• The trailer sits level when hitched
• Pins, clips, and the coupler latch are all secured

Our guide to towing capacity and payload covers the vehicle side of the equation. Follow us on Facebook for more towing tips.