I know, it's such a small thing, but you need a trailer ball so your tiny pick-up can safely bear the weight of hauling that huge boat.

Ivan Cholakov/iStockPhoto.com

You've got your boat mounted on your trailer, and you're getting ready to hook it up to the receiver hitch on your pickup truck. Suddenly, a problem arises that could derail your trip before you leave the house: Do you have the right trailer ball?

Trailer balls and switch balls are hitch accessories mounted on your receiver hitch's ball mount. It's the piece of towing equipment that couples the trailer to the towing vehicle and bears the load of the trailer's weight.

Trailer balls, also called hitch balls, are rounded to allow for lots of vertical and horizontal movement. After all, the hitch connection will be bouncing around a lot due to the motion on the road [source: Sierra Nevada Airstreams]. However, depending on what you'll be towing, it's important to make sure you have the right trailer balls equipped.

Sometimes, you may even need to swap out your ball for a different one, especially if you have to tow something you normally wouldn't. This is where switch balls come in - they can be changed on the fly in case you have to tow a small trailer one minute and a boat the next.

In this article, we'll discuss how to properly buy and hook up a trailer ball, so that you'll know exactly what you need when it's time to start towing.

­