Knowing how to read the specs on a trailer is key if you want to tow safely.
National Trailer Safety Week just ended, of course, but we’re big believers in trailer safety throughout the year. And while most of our customers are experienced haulers, we occasionally get new enthusiasts who are learning the technicalities of towing.
Those new folks come with questions about what all these crazy acronyms and specs mean, so we thought we’d offer a quick review of these terms. Plus, we wanted to slip in a few details about any differences you might notice with our hydraulic drop deck trailers.
Table of Contents
Curb Weight
Curb refers to the weight of the trailer when it’s sitting, unloaded, and parked at the curb.
Why does it matter?
Understanding your trailer’s curb weight is the baseline for other important calculations you’ll need to make before you take your load on the road.
It tells you the empty weight you’re adding to your towing vehicle (your car or truck) which directly impacts the load you can safely carry, and, ultimately, your total towing capacity. It’s the starting number, the one you need to ensure you don’t overload your setup.
Load Limit
The load limit is the maximum weight of cargo that can be safely loaded onto the trailer.
To determine your load limit, use the formula: (GVWR – Curb Weight = Load Limit).
Why does it matter?
This is perhaps the most practical number for haulers.
It tells you, directly, how much “stuff” you can put in your trailer. Exceeding the load limit puts stress on every component. It increases your accident risk and can mean incurring fines if you get stopped by law enforcement.
Always weigh your cargo!
Gross Trailer Weight
GTW is the weight of your fully loaded trailer, so it will depend, at least a little bit, on the weight of your cargo.
Why does it matter?
GTW is critical because it’s the actual weight your tow vehicle and hitch system need to manage.
This number must never exceed your trailer’s GVWR, your vehicle’s towing capacity, or your hitch’s rating. Exceeding GTW limits can lead to a loss of braking power, reduced steering control, excessive wear on your vehicle, or even the structural failure of your trailer or hitch.
Tongue Weight
Tongue weight is the downward force exerted by the trailer’s tongue (the part that connects to the hitch) onto the hitch ball of the tow vehicle.
Ideally, tongue weight should be 10-15% of the GTW for conventional trailers.
Why does it matter?
Proper tongue weight is absolutely critical for safe towing.
- Too little tongue weight (less than 10% of GTW) can lead to severe trailer sway, leading to a loss of control, especially at highway speed.
- Too much tongue weight (over 15% GTW) can overload your tow vehicle’s rear axle, compromising steering and braking by lifting the front of the vehicle. It can also cause excessive wear on the hitch and vehicle suspension.
Gross Axle Weight Rating
Technically, Good Trailers don’t have axles. Instead, we have a suspension assembly that does the same job. Nevertheless, the GAWR continues to apply. You don’t want to overload that assembly any more than you want to overload a traditional axle.
You’ll find this information on your VIN tag.
GAWR is the maximum gross weight the axle (or suspension assembly) can support. If your trailer has multiple axles, each one will have its own GAWR.
Why does it matter?
GAWR ensures each individual axle or suspension system isn’t overburdened. Overloading an axle can cause premature wear on tires, bearings, brakes, and the suspension components themselves.
It can also lead to dangerous trailer sway, a loss of control, and even axle failure, especially during turns or over rough terrain. Ensuring each axle remains within its GAWR contributes to overall trailer stability and longevity.
Gross Vehicle Weight Rating
You’ll find this information on your trailer VIN tag.
The GVWR is the maximum permissible total weight of the trailer itself when the trailer is fully loaded.
This includes the trailer’s curb weight plus all cargo and accessories. We set this rating for you here at GoodMFG, and add it to your VIN.
Why does it matter?
GVWR is crucial because it indicates the structural limit of the trailer itself.
Overloading a trailer beyond its GVWR can lead to catastrophic failures of the frame, suspension, tires, and axles.
It’s designed to ensure the trailer can safely carry its intended load without compromising its integrity or leading to blowouts and breakdowns.
Gross Vehicle Weight
GVW is the actual weight of the loaded trailer at any given time.
Unlike GVWR (the maximum rating), GVW is the real-time measurement of what your trailer weighs.
Why does it matter?
While GVWR is the manufacturer’s limit, GVW is what you’re actually pulling. Knowing your GVW helps you ensure you are always under your GVWR, GAWR, and GTW limits for safe operation.
You can determine GVW by weighing your loaded trailer at a truck stop or certified scale. Regularly checking your GVW ensures you haven’t accidentally overloaded your trailer for any given trip.
Towing Capacity
Your car or truck manufacturer should provide a towing capacity for the make and model of your car. This is the maximum weight your vehicle is designed to pull safely, including the trailer and its cargo.
Why does it matter?
This is the ultimate limit for your tow vehicle. Never exceed your vehicle’s stated towing capacity. Doing so can cause severe damage to your engine, transmission, and braking system. It can also overheat your car, reduce your ability to control your vehicle, and drastically increase your risk of accidents.
Always know your vehicle’s limits before you hook up a trailer at all.
Gross Combined Weight Rating
The GCWR is the maximum allowable weight of the entire vehicle and trailer combination. This includes the weight of the tow vehicle and the trailer, plus all passengers and cargo across both the trailer and the towing vehicle.
Why does it matter?
GCWR is the ultimate safety limit for your entire towing rig. It ensures your vehicle’s engine, transmission, brakes, and chassis are all capable of safely handling the total weight you’re pulling and carrying.
Exceeding GCWR is incredibly dangerous, leading to poor acceleration, overheating, brake failure, and instability, putting everyone on the road at risk.
Know Before You Go
Understanding these key specifications is fundamental to safe and efficient trailer operation. While it might seem like a lot of acronyms at first, each one plays a vital role in ensuring you can safely haul your cargo, protect your equipment, and arrive at your destination without incident.
Don’t forget to download your owners’ manual! Call us if you need help finding any of these figures. We’re happy to oblige.
See also:
5 Signs Your Trailer Needs Repair
4 Ways the Good Trailer Foldable Tow Bar Will Improve Jobsite Safety
