What is GCWR and How Does it Work?

What is GCWR and How Does it Work?

Trucks and cars have many numbers associated with them: torque, horsepower, fuel economy… all of these are well-known to drivers everywhere. How quickly a car can get from 0 to 60 is something that’s often discussed if you’re talking about sports cars, while if you’re discussing a sedan, there’s a good chance you’ll be familiar with the figures that describe the volume of the interior. If you’re planning to buy a truck or car these numbers are essential since they let you know clearly what you’re going to get for the price you pay.

However, even though these measures, weights, statistics and costs are all published and made available to drivers and vehicle buyers, some numbers relating to cars cause a lot of confusion. Most people, for example, have no idea what the GCWR of their vehicle is. That’s why we’re taking a closer look here at what this acronym means and why it’s such an important number to be aware of when it come to loading your vehicle safely.

What Is GCWR?

The term GCWR is an acronym that stands for “gross combination weight rating.” It may not be a term that many drivers are familiar with, but it’s certainly a number that’s important to know, especially if you’ll ever use your vehicle to tow a trailer. Whether you’re driving an SUV, truck or car, you should know what its GCWR is.

Sometimes, the GCWR of a vehicle is referred to by other terms. It may be known as the GCM (gross combination mass), the GTW (gross train weight) or even the MAM (maximum authorized mass).

So, what is GCWR? Essentially, the GCWR of a vehicle is a weight that has been determined by its manufacturer as the maximum weight that the vehicle can bear when fully loaded as a tow vehicle. It includes the trailer and any cargo in it, as well as the cargo inside the main vehicle. It’s vital to ensure that the total weight of the trailer and its tow vehicle shouldn’t exceed the listed GCWR of the manufacturer at any time.

The GCWR represents a function of the engine’s torque output, the ratios and capacity of its transmission, its tires and driving axles’ capacity, its radiator capacity, and finally the chassis’ ability to withstand the powertrain torque. If any of the components are a weak link, it could result in the transmission and engine having to work too hard. While the towing vehicle will continue to move the weight, it will need to use a lower transmission gear in order to move that weight and this will increase the engine’s RPM. As a result, fuel costs will increase and there will be more stress on the transmission and engine, thus increasing the chances of premature breakdowns and wear.

How Is the GCWR Calculated?


The definition of the GCWR doesn’t actually state how the rating is worked out. Yet, in general, it is calculated by combining the listed curb weight of the vehicle, the weight of its passengers and driver, the weight of the trailer and the allowable payload.

You should remember that the GCWR of a vehicle isn’t actually a measurement of the trailer and tow vehicle’s weight but the maximum combined weight limit which has been set by the manufacturer for both vehicles when they are attached to each other.

GCWR And GVWR – Is there a Difference?

The GVWR is similar to the GCWR of a vehicle, however they aren’t the same thing. As we’ve already discussed, the GCWR is the Gross Combination Weight Rating while the GVWR is the Gross Vehicle Weight Rating. The GCWR takes into account two attached, yet individual vehicles in the form of the trailer and tow vehicle itself.

Why Is GCWR Important?

The main reason to set a GCWR for a vehicle is to ensure its safety. If you overload a trailer or tow vehicle, that is already dangerous. However, if you overload both a trailer and a tow vehicle to the extent that it exceeds the GCWR, you’ve got a serious problem on your hands.

Heavy loads aren’t just hard to control when out on the roads, but there are a number of other components which may be at risk too. As an example, the braking system could overheat then fail. This would reduce, or possibly even eliminate, the ability to safely slow down or stop the vehicle. The tires could also present another problem. They may struggle to cope with an additional load and this could potentially cause a blowout to occur. The transmission and engine in the towing vehicle could also overheat because of the additional strain and this could result in mechanical failures. Meanwhile, components in the suspension system of the trailer may bend or break, and this could result in a loss of control when out on the roads.

Many problems can be caused as a result of overloading and this is why it’s so important to never exceed the GCWR of your vehicle. If you’re planning to tow a trailer with your car, it’s therefore a good idea to find out what the GCWR of your vehicle is.

How To Find Out Your GCWR Information

Taking the time to find out the GCWR information for your vehicle is important, but luckily, it’s quite easy to find. Usually, you will find it printed on a label which is stuck inside the frame of your vehicle’s door, close to the latch area of the driver side door. If you cannot find a sticker in this location, you can look for the key information online. Most manufacturers publish this detail along with other key information about your car online on their websites, so all you need to do is perform a search to get the details. That way, you know you are within the appropriate load limits for your vehicle.

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