12 Things To Consider When Upgrading A Trailer’s GVM Rating

Overloading a vehicle may not only be dangerous but also illegal. Despite the apparent risks associated with it, most drivers are oblivious to the problem. Nonetheless, one simple way of avoiding overloading your trailer is upgrading its GVM.

In case you didn’t know, GVM stands for gross vehicle mass. Its rating includes the total weight of the trailer and its maximum permissible load. If you have a trailer weighing 200 kg with a capable supporting weight of 800 kg, then the GVM should be 1,000 kg. If you exceed 1,000 kg, then you’re overloading your trailer.

Now that you know what a trailer’s GVM’s about, you may want to do an upgrade so you don’t break the law. But first, there are a few things to consider when applying your upgrade, and these include the following:

What Do You Need To Carry?

The first thing you’ll need to think about is the load you intend to carry with your trailer. An estimate of the weight will be helpful in deciding the GVM rating you’re upgrading to. You wouldn’t want to be upgrading to a rating that’s lower than the load you want to or usually carry. The trailer’s use should determine its design.

An appreciation of what you plan to carry can also help with the selection of materials to be used in the design and overall upgrade of your trailer. For example, if you want to use the trailer for carrying water, the floorboards of your trailer can be rubberized or galvanized during the upgrade to prevent rusting or leaking.

Consult A Professional

GVM upgrades are no easy job; there are many safety issues to consider to keep within existing rules and regulations. Upgrades typically involve a complete overhaul of the components of your trailer such as

  • replacing the springs,
  • upgrading the axles,
  • changing tires and brakes, and
  • upgrading the coupling, among others.

If you have no mechanical background or auto-engineering knowledge, employ the services of professionals. There are many different parts to upgrade for GVM rating available on the market, so you could do well by leaving the headache to professionals.

They’ll often give you the best advice for your upgrades. Professional services will also have packages with safety nets for your investment such as warranties and certification.


Make sure your trailer is compatible with the proposed GVM upgrade. If your chassis is rusty, for example, it may fail to hold the weight of your proposed GVM rating. The tires and the spares you have should also be the correct ones rated for your trailer. For example, the design of a horse trailer will be different from the one on a caravan, so how you’ll use and how often you’ll use your trailers will also determine the parts you’ll need.

Safety And Effectiveness

Depending on the intended use for your trailer, there are many safety concerns to think about. Your GVM upgrade should give your trailer not just a higher carrying capacity but also the recommended safe and suitable handling requirements, especially for road use.

Availability Of Parts

You have to think about the new parts or spares needed in upgrading your trailer. For the upgrade to be a success, it’s recommended to ensure that the spares used are from reputable manufactures. The parts also have to be for a GVM rating which is higher than the intended one. This could help you avoid unintentionally overloading your trailer.

Turnaround Time

GVM upgrades generally take three to five days. If parts aren’t readily available, this may take weeks or up to a month. It’s worth knowing the job timelines to help you with your planning. Just be sure never to rush the job. They say perfection requires a handful of time.


GVM upgrades done by accredited professionals will typically offer some reasonably good warranties on their modifications. Consider their options so that your improved trailer is covered by the best warranty for your budget. On the other hand, if you decide to do it all by yourself, think about ways of getting certifications which could give you some sort of warranty. Remember, without the proper research, doing this yourself may take longer than expected.


Some states have compliance certification requirements for trailers. Depending on where you come from, there might be some certification need for your upgraded trailer. It may be worth checking with your local authorities in case you step out of the confines of the law.

Registration Cost

GVM ratings are likely to change the tare ratings. The weight of the trailer usually determines the cost of registration. Before you do your upgrade, calculating the registration costs involved is advised. The cost difference is, however, not astronomical; but they’re nonetheless worth considering.

Insurance Coverage

Consider the insurance coverage of your GVM upgrade before you decide anything. Some insurers have higher premiums for upgrades, so be sure to contact your insurer before you go ahead with your upgrade so your policy may be in tandem with the changes done to your trailer. Your insurer will also typically not cover the damage for GVM upgrades—be it CTP (compulsory third party), third party, or comprehensive insurance.

Proper Testing

The point of a GVM upgrade is to ensure your trailer is safe and sound on the road. Otherwise, there’s no point in doing it if you don’t do it right. Make sure that proper testing is done so you can rest assured that the proposed load capacity is actually what’s on the ground. Cheating your way around it or taking shortcuts will be detrimental to no one but yourself.

Your Vehicle’s Towing Capacity

You may be excused for assuming that your vehicle could still pull the new load capacity if you do a GVM upgrade on your trailer. The misassumption is, however, quite common; but it could potentially cause mechanical damage to your car. Just because your trailer has an improved GVM rating doesn’t mean your car’s pulling capacity has changed. Therefore, it’s important to consider your car’s towing capacity.

In A Nutshell

There are many reasons you may want to do a GVM upgrade. One good reason is when you could be overloading your trailer. Forgetting this upgrade once is negligible; many times, you’re only endangering yourself and others on the road. But neither should be an excuse. The next time you can, take your trailer to the nearest weighbridge and get your rating.

If you realize that you’ve been overloading your trailer, do the right thing and do a GVM upgrade. Doing a GVM upgrade can be cheaper than getting a new trailer. But just be sure to get professionals to take a look at the job that needs to be done. Your safety and that of others depend on it.