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Understanding Towing

Towing 101Truck towing boat trailer

1. Introduction to Towing

2. Basic Towing Equipment

3. Types of Trailer Hitches

4. Towing Capacity

5. Selecting a Trailer Hitch

6. Trailer Hitch Installation

7. Towing Electrical & Wiring

8. Trailer Brakes & Brake Controls

9. Hooking Up Your Trailer

10. Towing Safety


Chapter 5: Selecting a Trailer Hitch

Answered in this chapter:

How do I select a receiver hitch?

How do I choose a ball mount?

How do I choose a trailer ball?

Do I need a weight distribution hitch?

How do I select a 5th wheel or gooseneck hitch?


Selecting the right trailer hitch for your vehicle can actually be one of the easiest steps in getting ready to tow. If you already know the weight capacities of your vehicle (see chapter 4 if you do not) and you know the type of trailer you are planning to tow, then it is only a few simple steps to finding the right hitch.

In this chapter, we will discuss how to select a receiver hitch for your specific vehicle, as well as the right ball mount and trailer ball to complement your towing setup. We will also discuss the selection process for heavy-duty hitch applications, such as in weight distribution, 5th wheel and gooseneck towing.


How to Select the Right Receiver Hitch

Most receiver hitches are designed to be vehicle-specific, making selection fairly easy. One of the best ways to find the right fit for your vehicle is to use the CURT Select Your Vehicle tool on our trailer hitches page. Simply enter the year, make, model and style of your vehicle, and the search results will show all receiver hitches that are compatible, including front mount and rear mount options. It will also show custom wiring harnesses that are able to fit your specific vehicle.

Remember, a hitch is only one component of a towing system. The responsibility for knowing the capabilities of your vehicle and equipment is up to you. Take a moment to watch the "How to Select a Trailer Hitch" video for a general guide to choosing a trailer hitch.


Matching Maximum Weight Carrying Capacity

Weight carrying capacity is one of the biggest factors in determining which trailer hitch to choose. If you are towing with a minivan or sedan, your choices will probably be within the class 1, class 2 or possibly class 3 range. On the other hand, if you have a full-size pickup truck or SUV, you will probably be able to choose from classes 3, 4 or 5.

To help you get an idea of what hitches fit with which tow vehicles, the table below shows the possible relationships between the two. Remember that these are representations only and do not reflect any actual vehicles. Also, not all vehicles within a particular category will be compatible with each hitch class listed.

Vehicle type and hitch class comparison


How to Choose a Ball Mount

After you have selected a receiver hitch, you will also need to select a ball mount. The right ball mount should have a shank size that matches the receiver tube opening of your hitch, a weight rating that meets or exceeds your gross trailer weight and a rise or drop to help level your trailer.

Consider the scenario shown in the diagram below. The height of the receiver tube (A) is greater than the height of the trailer coupler (B). When you tow, you want your trailer to be as level as possible. Because the receiver tube is higher than the trailer coupler, the ball mount is used to make up the difference (C).

How to determine ball mount drop or rise

Most ball mounts are made with "drop" or "rise" to help level the trailer. When the receiver tube is positioned higher than the coupler, a ball mount with drop will make up the negative difference. When the coupler is positioned higher than the receiver tube, a ball mount with rise will make up the positive difference. The figure above shows a ball mount with drop, indicated by measurement C.


Determining Drop and Rise

To find the measurement of drop or rise for your tow vehicle and trailer, you will need to measure the receiver tube height (A) and the coupler height (B). B minus A equals C, the drop or rise needed. If C is a positive number, your ball mount will need to have rise. If C is negative, your ball mount will need drop.

In general, you will want to select a ball mount that sits slightly higher than the coupler to account for the trailer's tongue weight.

Your trailer dealer can help you choose a ball mount with the correct amount of drop or rise. Many ball mounts are designed to work in either the drop or rise position, allowing you to accommodate various trailer heights.

Also, be aware that you can adjust drop or rise by selecting a trailer ball with a shorter or longer neck.

To browse a complete selection of CURT ball mounts, visit our ball mounts page.


How to Choose a Trailer Ball

Another component to add to your trailer hitch is a trailer ball. Some ball mounts come with a trailer ball already attached, whether bolted on with a nut or welded on.

Most ball mounts will require you to purchase a trailer ball separately and you will need to select one that fits your towing setup. You will need to know the coupler size, the trailer ball hole diameter of your ball mount and the weight of your trailer.


How to measure a trailer ball

Coupler Size

For the coupler size, most manufacturers stamp or label the correct trailer ball size on the coupler. Use the measurements in the diagram to help select the right size trailer ball for your towing setup. Make sure that your coupler and trailer ball have a solid connection before towing and that all necessary adjustments have been made.


Trailer Ball Hole

The hole in the platform of a ball mount or trailer hitch tongue is where the trailer ball bolts onto. It is important to know the diameter of this hole so that you can choose a trailer ball with a matching shank diameter. If the trailer ball shank is too small, it will shift while towing and tend to come loose. If the shank size is too small for the trailer ball hole, you may be able to use a reducer bushing to make up the difference.


It is also very important to torque the trailer ball nut to the correct foot pounds, based on its shank diameter. Trailer ball installation will be discussed further in chapter 6.


Weight Capacity

As was the case when selecting your trailer hitch and ball mount, weight capacity must be considered when choosing a trailer ball. The weight rating for a trailer ball will be listed as the ball capacity. This will reflect the gross trailer weight limit, not the tongue weight. You must select a trailer ball with a ball capacity that exceeds the gross weight of your trailer.

To see a complete selection of CURT trailer balls, visit our trailer balls page.


Adding a Weight Distribution Hitch

Weight distribution hitch and sway control unit If your trailer weighs more than 3,500 lbs., you may want to invest in a weight distribution hitch. As discussed in chapter 2, a weight distribution hitch is a receiver hitch attachment that levels out your trailer and vehicle by distributing some of the tongue weight across the axles. It may also increase the overall gross trailer weight capacity, based on your specific trailer hitch. Remember, you must always abide by the lowest rated towing component in your towing system.

Weight distribution hitches are compatible with most class 3, class 4 and class 5 receiver hitches. However, some hitches are only rated for weight carrying applications. Verify the compatibility of your own particular hitch before towing.

Installing a weight distribution hitch tends to be fairly in-depth. In chapter 6, we will go through some of the common steps involved in setting up a weight distribution hitch. Be sure to follow all manufacturer's instructions concerning when and how to use a weight distributing system.

To browse our selection of WD hitches and sway control products, visit our weight distribution page.


Selecting a 5th Wheel or Gooseneck Hitch

Ford Super Duty truck towing gooseneck livestock trailer For some applications, your choice of trailer hitch may already be decided because of the type of trailer you are planning to tow. Namely, if you have a 5th wheel trailer, you will need a 5th wheel trailer hitch mounted in the back of you pickup truck to haul it. The same is true of gooseneck trailers. A gooseneck trailer must be towed using a gooseneck hitch or a gooseneck hitch adapter attached to 5th wheel base rails.

Keep in mind that even with these specialized hitches, you will still need to consider the weight capacities of your towing system, vehicle and trailer. 5th wheel hitches range from 16,000 lbs. to 25,000 lbs. in capacity, and gooseneck hitches are typically rated to tow up to 30,000 lbs. You will need to know how much your trailer weighs and verify that your truck is rated to tow the heavy load, using your owner's manual.

To find a CURT 5th wheel hitch, visit our 5th wheel page, or to find a CURT gooseneck hitch, visit our gooseneck page.


If you are ready with the right hitch, the right ball mount and the right trailer ball, let's move onto some of the common steps involved when installing these components.


< Chapter 4: Towing Capacity

Chapter 6: Trailer Hitch Installation >