How much can I really tow?

by Stephen Haughey, Consultant, IPWEA Fleet and Chief Instructor, XDrive

What a lot of vehicle manufacturers fail to mention is that hauling a vehicle (e.g., trailer, float, etc.) up to your maximum towing capability can sometimes affect the amount of weight you can carry. Depending upon the situation, this may impact the legal weight and lead to serious consequences.

To highlight this, I have used the Ford PX Ranger as an example. The PX-series has been a commonly used mid-sized utility designed and engineered by Ford Australia and based on Ford’s T6 platform.

First, let’s look at a couple of the vehicle’s weight ratings. The Gross Vehicle Mass (GVM) for the Ranger is 3,200kg. GVM is the maximum the vehicle can legally weigh. However, this figure may vary between different model types of the same vehicle due to differences in trim, engine, or body style. The Gross Combined Mass (GCM) for the Ranger is 6,000kg. GCM measures how heavy the vehicle and trailer can legally weigh. Normally this is the equivalent of the GVM and the Aggregate Trailer Mass, but this is not always the case.

Also, for this example, we are using Gross Trailer Mass (GTM) and Aggregate Trailer Mass (ATM) as mentioned above. GTM is the weight of the fully loaded trailer imposed on the trailer’s axle when it is coupled to the tow vehicle. ATM is effectively the Braked Tow Rating or how much the trailer weighs (essentially the trailer equivalent of GVM in a vehicle). Note that GTM will always be less than ATM as some of the trailer weight is transferred to the tow vehicle when the trailer is coupled to it.

Ford advertised that the Ranger could tow a maximum of 3.5 Tonne, which it does. However, if you take a closer look at the vehicles specifications you will see that the GCM cannot exceed 6000kg. Therefore, if you take 3500kg max towing capacity from the GCM that leaves you a maximum allowable vehicle weight of only 2,500kg.

Basic GCM example: 6000kg - 3500kg (max towing) = 2,500kg

Therefore, you’ll need to take 700kg out of your maximum allowed GVM figure of 3,200kg to be able to tow 3.5T with the PX Ranger. It’s more of an eye-opener if you look even further into the vehicle specifications.

Let’s assume that you are still towing the maximum amount of 3.5T (GTM) with the PX Ranger, which we will say is a Dual Cab XLT. In this case, we will also use the Vehicle Tare (or Kerb) Weight, which is how much the vehicle weighs in standard configuration. Keep in mind that there is no agreement amongst manufactures as to what this ‘standard’ configuration entails. Unfortunately, some descriptions of this measurement refer to “full of fuel” and others refer to “small amounts of fuel” e.g., less than 10 litres. Also, some manufacturers allow for the driver and others have no allowance.

GVM (with max towing) example: 2,500kg - 2,159kg (Vehicle Tare Weight) = 341kg

So, you are now left with a payload of 341kg. Let’s take out a couple more essential items from that figure to understand the full extent of the problem.

Advanced GCM example: 341kg (Payload) - approx. 280kg (Tow Ball Down Force) – approx. 70kg (Fuel) = - 9kg

Therefore, on a Ford PX Ranger XLT towing a 3.5T trailer (GTM) with a full tank of fuel and approximately 280kg of ball weight you are already over your GCM.

Now try to add a driver, additional passengers, any luggage, a fridge, bull bar, winch etc. and you will be well over your allowable limit. This makes your vehicle un-roadworthy and in the case of an accident you risk voiding your insurance payout. As you can understand, this is important information that the consumer really should be made aware of and you as a fleet practitioner should fully understand.

Stephen Haughey is a consultant with IPWEA Fleet. He is also the founder of XDrive Advanced Driver Training, which is a leading Four-Wheel Drive and Driver Training provider in Australia. Stephen is the highest qualified Four-Wheel Drive Trainer in Australia and the only Four-Wheel Drive trainer in Australasia certified by the International Four-Wheel Drive Trainers' Association. Click on the link for more information.