Understanding the Limitations of Hitch-Mounted Carriers

When you decide to increase your transport space with the use of your vehicle’s trailer hitch, you might assume it’s a plug-and-play situation where as long as you marry a 2” carrier hitch to a 2” vehicle hitch receiver, you’ll be able to transport anything.

The reality is that it’s a little more complicated than that, and the more you understand the factors that go into safe use, the safer you will be on the road to yourself, your vehicle, and others.

Hauling a hitch-mounted carrier is NOT the same as towing a trailer

When towing a trailer, your vehicle will experience forward/backward forces as well as side-to-side forces.

When hauling a hitch-mounted carrier, your vehicle will experience varying up-and-down forces. We say “varying” because your traveling speed and the bumpiness of the road will all play a role in how much force is exerted straight onto that hitch from the carrier.

Before you purchase a carrier, it’s important to understand the factors that affect how your vehicle will be impacted with a carrier, and how a carrier will be impacted by your vehicle. The end goal is to ensure that your vehicle and carrier won’t be overloaded, and won’t create unsafe driving conditions.

Factors that Affect Hitch-Mounted Carriers

Vehicle

• The vehicle type
• The vehicle’s tongue weight capacity rating based off the frame of the vehicle
• The hitch class, size and capacity
• The hitch height from the ground
• The shocks, struts and general vehicle condition

Carrier

• The weight of the carrier
• The total weight of the cargo
• Anti-tilt brackets or pinch bolts

The Vehicle Type

Crossovers, larger passenger cars and pickup trucks with hitches are the ideal vehicles to use with hitch-mounted carriers. Sedans should never be used with hitch-mounted carriers because of how low they sit to the ground. With few exceptions, the majority of carriers should never be used on tow-behind trailers, 5th wheel, camping trailers, motor-homes or RVs. Although that seems harsh and limiting, it’s for your safety and that of other drivers. Those types of vehicles create too much of a dynamic load on the carrier caused by the long distance from the rear axle of the trailer or RV to the trailer hitch.

What does that mean? The suspension creates far too much bounce than most carriers can handle, resulting in carrier failure and damage to the cargo, carrier, and/or vehicle.

Why it’s important: If you install a carrier on the wrong vehicle type, you could run the risk of damaging your vehicle, your carrier and your cargo, as well as creating a hazardous situation for other drivers.

The Vehicle’s Tongue Weight Capacity Rating Based off its Frame

From the very start of its manufacturing process, a vehicle’s chassis, or frame, is built to handle a certain amount of overall weight and a certain amount of weight on its hitch, regardless of whether it’s a hitch-mounted carrier that’s exerting downward force on the hitch tongue, or tow-behind trailer exerting both downward force on the tongue and a towing force.

There are several weight capacity check points you should identify up front to make sure that nothing you’re transporting will overload your car or truck. Many vehicle frames have a different weight capacity set for towing and transporting than their hitches, and the rule of thumb is to always go by the lowest weight rating. Many experienced hitch users take the lowest weight rating and subtract 50 to 75 pounds just to be on the safe side to ensure that their vehicle will be able to handle everything it transports by hitch.

Body-on-frame chassis are typical for trucks and older vehicles, however a lot of modern crossovers and other cars feature a unibody chassis. Because of the integrated body and frame design, unibody chassis are not usually rated for hauling hitch-mounted carriers, as the frames do not handle the downward force while in motion. However, they are able to tow, and as such it is possible to calculate a towing tongue weight capacity based on that towing weight rating. It’s important to note that the towing tongue weight rating does not mean the same thing as the hauling tongue weight rating!

Gross Vehicle Weight Rating (GVWR)

This is the maximum amount of total weight that your specific vehicle model can handle safely, including the driver, passengers and cargo. This number is set by the vehicle manufacturer.

Why it’s important: When transporting heavy hitch-mounted cargo, make sure you’re not transporting an excessive amount of inside cabin cargo or rooftop cargo that might overload your vehicle’s weight.

 To find: Look at the information panel inside the driver’s side door, or refer to your owner’s manual.

 Example: The 2022 Jeep Grand Cherokee has a GVWR of 6,050 lbs.

Tongue Weight Capacity (TWC)

Unlike the GVWR, tongue weight capacity (TWC) refers specifically to the maximum vertical weight that your vehicle’s hitch can support under normal driving conditions. There are two tongue weight capacities that you should be aware of: towing and hauling.

When calculating the towing tongue weight capacity, the rule of thumb is often calculated as 10-15% of the vehicle’s towing capacity. That can sometimes be incorrect, as there are ways to increase your towing capacity, such as installing stiffer shocks or struts and a larger cooling fan and/or radiator, however this will not impact the tongue weight capacity. For example, a 2018 Chevy Silverado can tow up to 9,400 lbs. yet only have a tongue weight of 500 pounds. Towing capacity can be changed with upgrades, but tongue capacity cannot. Never exceed the maximum tongue weight of your trailer hitch.

Why it’s important: If there is too much downward force exerted on the tongue, it could damage your hitch or your vehicle, and render your vehicle less responsive when turning and braking.

 To find: Unfortunately, there’s no one-size-fits-all answer. Each vehicle’s hauling tongue weight will be different depending on chassis type, year, make model, hitch and vehicle condition. If you have a factory-installed hitch, look for a weight sticker directly on the hitch. If you have an aftermarket hitch installed, the maximum tongue weight capacity should be listed on a weight sticker, or you can look it up on the internet using the manufacturer part number. You should never just go off the tongue weight of the hitch, but rather consider it as one piece of the larger tongue weight calculation specific to your unique vehicle.

 Example: The 2022 Suburu Outback w/4-Cylinder Boxer Engine has a towing capacity of 2,700 lbs. and a tongue weight capacity of 270 lbs. with the factory-installed Class II/III hitch.

Hitch Class, Size and Weight Capacity

The majority of hitch-mounted carriers are designed to work with Class III and IV hitches. Unless specifically stated in the product description or instruction manual, Class I and II trailer hitches (1-1/4”) do not have a hefty enough weight capacity to be able to support the type of weight typically transported by carriers.

Hitch adapters and extensions are intended to help carriers fit better on specific vehicle make and models, however most are not recommended for use with hitch-mounted carriers because they could alter the maximum weight capacity and create unwanted sway or movement during transport. Our rule of thumb: If they are not specifically designed to be used with the product you purchased, do not use them! Hitch adapters reduce the vehicle’s tongue weight by 50%. While there are a couple of exceptions (our foldaway motorcycle carrier adapter, our SC-400 and SC-500 adapters), any adapter that modifies the distance from the bumper, the height from the bumper, or makes your hitch opening smaller or larger will reduce the vehicle’s tongue weight.

Why it’s important: The hitch class and size will determine the fit between the hitch tube and the hitch receiver, and acts as a guideline to how much weight the hitch can support under ideal circumstances (good suspension condition, etc.).

 To find: If you aren’t sure what hitch size/class you have, measuring the opening of the hitch tube horizontally or vertically is a quick way to tell.

 Example: The 2020 GMC AT4 2500 Duramax comes with standard with a 2-1/2” hitch receiver opening.

Hitch Height from the Ground

If your vehicle sits low to the ground due to mechanical or suspension issues, the hitch will also be lower to the ground. This can cause problems if you add a carrier and cargo, not to mention once you start driving and hitting bumps. Oftentimes this is caused by worn shocks or struts which will lead to the carrier appearing to sag or droop – even if the hitch can support the weight of your loaded carrier.

Shocks, Struts and Vehicle Condition

As we touched on briefly in the last section, the condition of your vehicle plays into how much weight your hitch can safely support. Older vehicles, or those with struts and shock issues, may require some modifications or repairs before safely hauling cargo. The addition of air bags, air shocks and/or heavier springs and struts can help stiffen up the suspension and prevent sagging.

Why it’s important: We have had previous customers purchase a cargo carrier perfectly suited for their vehicle, then give us feedback that their carrier is droopy and doesn’t look level. Photos and feedback then reveal that their vehicle’s suspension is simply unable to handle the weight, even though their rating is well within the appropriate range of the carrier.

 To find: Although you can perform a visual inspection on your own vehicle, we recommend having a certified mechanic visually inspect every part involved in your vehicle’s suspension.

Carrier Weight Capacity

All carrier manufacturers have a maximum weight capacity for their carrier models. It might seem like common sense, but you should never exceed the recommended maximum weight capacity rating of the carrier.

Why it’s important: Exceeding the weight rating puts additional stress and strain on your carrier, which can result in damage to the product, damage to your vehicle or others (particularly if it occurs while the vehicle is in motion), and potential injury to anyone near the carrier when and if it fails. Exceeding the weight capacity of the carrier is considered improper use and will invalidate your warranty, and if it leads to damage to your vehicle, please note that many car manufacturers also consider exceeding the tongue weight as improper use, which can also invalidate any warranty you might have on that vehicle.

 To find: Because of its importance, weight capacity will be readily available on the sales listing, in the instruction manual, and printed on the physical carrier.

Cargo Weight and Distribution

Know the weight of your cargo before you purchase a hitch-mounted carrier. By knowing how much weight you want to transport up front, you can make a smart purchasing decision and use the cargo weight to ensure that your vehicle and hitch can handle it.

If you’re not transporting a full load, always secure the majority of the cargo over the center of the hitch tube on the carrier to ensure even distribution. If the load is skewed to the left or the right, you’ll not only notice worse handling as you drive, it could create a safety hazard.

When loading up a vehicle such as mobility device or motorcycle, never ride it up or off the carrier. There are two safety reasons behind this: it’s incredibly dangerous to the rider should they fall off, and it adds unforeseen weight to the carrier and hitch that could overload the set-up and irreparably damage either the carrier or your vehicle. It’s much safer to push the vehicle up and off the carrier.

Why load distribution is important: A load that is not balanced properly can negatively affect handling while driving, and cause dangerous uneven wear along the carrier tube.

 To find the weight of your cargo: The weight of larger items and equipment will be listed by the manufacturer either online or in the owner’s manual. Smaller items can be weighed using a home scale and the total calculated manually.

Anti-Tilt Bracket and/or Pinch Bolts

Reputable carriers should ship with an anti-tilt bracket or pinch bolts to stabilize the carrier once it’s installed on your vehicle hitch. Both methods reduce sway and side-to-side movement, and should always be used if available to increase safety on the road when the carrier is in use.