When it comes to safe towing, it’s essential that you know how to evaluate and select each component of your hitch system. Each towing situation is different. Consequently, each piece of towing equipment must be exactly suitable for your individual set-up. In this step-by-step guide, we’ll cover how to choose a trailer ball hitch size specific to your coupler, your ball mount and weight requirements.
What is your trailer’s GVWR? What’s the size of your trailer’s coupler head? Why is tongue weight so important? How do I know how much rise or drop I need?
Let’s start at the beginning…
What is a Hitch Ball?
A hitch ball (or trailer ball or tow ball) is the ball-shaped attachment that connects the trailer to a hitch. The ball allows the trailer to pivot, providing smooth turning while towing. While the diameter of the hitch ball is fairly standard, hitch ball weight ratings may differ. The rating of your hitch ball is just as important as your receiver hitch rating.
What is a Ball Mount?
A ball mount is a removable hitch ball platform with a shaft that slides into the receiver tube of your truck and fastens with a pin and clip. Different ball mounts can be used to raise or lower the height of the tow ball to allow for level trailer towing.
3 Standard Trailer Ball Hitch Sizes
5 Most Important Things to Consider When Selecting a Ball Mount
#1 – How much weight will you be towing?
There is a comprehensive range of ball hitch sizes – and weight capacities range from 2,000 up to 30,000 pounds. When selecting a trailer ball (like any towing accessory), weight capacity must always be considered.
Need to quickly calculate your truck and trailer’s tow capacities? Check out our easy-to-use formulas in our Definitive Guide to Safe Towing.
To verify your trailer’s weight, locate the Federal Certification/VIN label on the front half of your trailer. It should be located on the left side. Specifications on the label should include:
- GVWR – Gross Vehicle Weight Rating (the total maximum amount your trailer can safely weigh when loaded).
- GAWR – Gross Axle Weight Rating (the maximum amount of weight that can be placed over each axle)
- Payload Capacity – the maximum amount of cargo weight that you can safely load onto your trailer (your trailer’s load limit)
- Trailer Weight – this is how much your trailer weighs empty
✅ The weight rating of your tow ball must match or exceed your trailer’s GVWR.
Use these charts to help you determine which tow ball can safely tow the weight of your trailer:
#2 – What tow ball diameter does your trailer’s coupler head require?
Most trailer manufacturers stamp or label the correct trailer ball size on the coupler (the front part of your trailer, designed to latch onto the tow ball). A trailer needs to have a ball that perfectly matches the size of its coupler. Let’s say your trailer comes with a 1-7/8” coupler. You’ll need a 1-7/8” tow ball on your hitch’s ball mount. This ensures that your coupler and trailer ball have a solid connection.
You can also take the measurement of your trailer’s coupler head yourself. Just use a tape measure, or ruler, to measure the inside opening of the coupler. This measurement is the size of the trailer ball needed.
✅ The diameter of your tow ball must match the size of your trailer’s coupler opening size.
#3 – What size and class of receiver does your truck have?
Receiver hitch classes are separated by their maximum weight capacity rating and receiver opening size. Classes range from I to V, and each class has its own unique capacity and applications. You can start by using the chart below to determine which class of receiver hitch your truck features:
Pro Tip: The best way to measure your receiver hitch tube is to measure the inside of the tube opening. Most likely it will be either a 2″ or 2-1/2″, which is often found on most pickup trucks.
An example with numbers: If you’re going to pull a trailer with a GVWR of 4,000 lbs, your truck must feature, at least, a Class III receiver hitch to pull your fully-loaded trailer safely. And, your ball mount will need to feature a 2” shaft that will fit into the 2” opening of your truck’s hitch receiver.
✅ The shaft of your ball mount must match the size of your truck’s receiver tube opening.
#4 – How much rise or drop do you need to provide a level and safe towing setup?
When loaded, both your truck and trailer must be level with the ground. If your trailer rides lower or higher than your truck, a specific ball mount can be used to make up the difference and ensure the trailer is level.
Use these formulas to determine how much of a drop, or rise, your ball mount requires to meet the height of your loaded trailer:
Drop Length Formula (for trailers that ride lower than your truck)
- Measure the distance from the bottom of your trailer’s coupler to the ground (be sure your trailer is loaded and sitting level with the ground while you measure).
- Subtract this number from the height of your hitch receiver (distance from the top of the inside of your truck’s hitch receiver to the ground).
- This is the required drop length of your ball mount.
Rise Length Formula (for trailers that ride higher than your truck)
- Measure distance from the bottom of your trailer’s coupler to the ground (be sure your trailer is loaded and sitting level with the ground while you measure).
- From this number, subtract the height of your hitch receiver (distance from the top of the inside of your truck’s hitch receiver to the ground).
- This is your required rise length of your ball mount.
Pro tip: Be sure your trailer is exactly level with the ground by placing a level on the top of your trailer’s coupler. Use the crank on your trailer jack to adjust the height, up or down, until the level is plumb, then take your measurement.
✅ Your ball mount must meet the height of your loaded trailer
The Weigh Safe Adjustable Drop Hitch comes in an array of different drop lengths ranging between 4 to 10 inches, each with 1” increments for adjustability. All of which can be used in both the drop or rise position.
Need help deciding which size draw bar you need?
It’s important to note that the “drop length” of a hitch is not the same as its “total length”. All Weigh Safe Draw Bars are 3 inches longer than their listed drop length. To ensure adequate clearance from the ground, use this formula to choose the right drawbar size for your adjustable trailer hitch:
Hitch Clearance Formula
- Find your required drop length (use drop length formula above).
- Add 3 inches.
- This is your total hitch length. Subtract this number from the height of your truck’s hitch receiver (distance from the top of the inside of the hitch receiver to the ground).
- This is your hitch’s amount of clearance and should be no less than 13 inches when the hitch is unloaded (uncoupled from the trailer).
- Your hitch’s clearance should be no less than 11 inches when the hitch is loaded (coupled to the trailer and bearing tongue weight).
Here’s an example with numbers. Let’s say that you own a Ford F350 pickup truck. You’ve measured 24.5 inches from the top of your hitch receiver to the ground. You’ve considered purchasing a hitch with a 10-inch drop, for plenty of vertical height adjustment options. However, a Weigh Safe Drop Hitch with a 10-inch drop, has a total length of 13 inches.
Using the hitch clearance formula, you calculate that 24.5 inches minus 13 inches would only leave you with 11.5 inches of clearance, unloaded. Ultimately, you decide to invest in a hitch with a drop length of no more than 8 inches, so that you’ll have plenty of clearance, especially, when your trailer is fully loaded.
How to Choose the Right Size Hitch Video
# 5 – How will you measure your trailer’s tongue weight?
Those who tow within their load’s target tongue weight have a huge safety advantage that is hard to overstate. Safe towing requires a certain amount of downward pressure on the hitch ball, called tongue weight, to ensure that the trailer will tow straight and remain stable. In all cases, it is not the weight itself that matters, it’s what tongue weight represents: that the trailer’s center of mass is situated ahead of its axle.
For safe towing, the recommended amount of tongue weight is 10% – 15% of your loaded trailer’s weight.
A Weigh Safe Trailer Hitch is the only hitch with a built-in scale to accurately measure your trailer’s tongue weight
✅ Always measure the tongue weight of your trailer before you tow
Is there a one-size-fits all universal trailer ball?
Technically, no. This is because each towing set-up is different. For safe towing, it’s imperative that you choose a tow ball specific to your coupler, ball mount and weight requirements.
However, we can introduce you to the secret weapon for towing numerous trailers on an array of different tow vehicles with one single hitch…
The adjustable Weigh Safe Drop Hitch is the easiest solution for:
- measuring tongue weight
- making vertical height adjustments
- switching between different tow ball sizes
- towing a variety of trailer types
The Most Common Ball Hitch Size
A 2-inch trailer ball is the most common hitch ball size. The 2-inch tow ball is the best fit for most class 3 receiver hitches – which are the most popular trailer hitches.
The Most Common Ball Hitch Size for Travel Trailers
The hitch ball used to tow most travel trailers is a 2-inch or 2-5/16-inch trailer ball. Travel trailers can weigh anywhere from 5,000 to 10,000 lbs or more. The 2-inch to 2-5/16-inch ball weight ratings provide a perfect match.
Additionally, many travel trailers are pulled using a weight distribution hitch. Our True Tow Weight Distribution Hitch comes standard with a 2-5/16-inch ball.
Do You Need a Weight Distribution Hitch?
Your truck’s owner’s manual should provide you with specifications regarding weight distribution use. For instance, the 2018 Chevy Traverse owner’s manual states that weight distribution and sway control are required when towing a trailer over 5,000 lbs. Most commonly, this applies to heavier cargo trailers such as campers and toy haulers.
You can also use this checklist to determine if you need a weight distribution hitch:
Indicators You Need A Weight Distribution Hitch:
- Your trailer weight (GTW) is more than 50% of your truck’s weight (GVWR)
- The rear of your truck sags when the trailer is hooked up
- You experience trailer sway
- Your truck’s headlights point upward
- You find it difficult to steer or stop
- You want to tow at your truck and trailer’s highest capacity
If you’re ready to install a weight distribution hitch, you can begin by reading our Complete Guide to Towing with a Weight Distribution Hitch.
Do You Need a Gooseneck Ball?
Towing heavy-duty sized loads – such as horse trailers, construction equipment, or RV’s – means towing heavy loads weighing 16,000 – 30,000 lbs, or more. Only pick-up trucks equipped with a towing system for a gooseneck hitch can tow this kind of weight.
If you’re ready to purchase a gooseneck ball, you can read our Definitive Guide to Heavy-duty Towing.
If you check-off each step in this guideline, you’ll be well on your way to finding the hitch ball size you need for safe and confident towing!