Know What You Tow


HaulGauge measures vehicle-caravan "gross combined weight", hitch weight, vehicle payload. It does this all  in real-time with an OBD-II connector. This is a small wireless device that plugs into your vehicles ODB-II outlet. It communicates wirelessly via Bluetooth with an app on your iPhone or Android device.


HaulGauge is an Artificial Intelligence (AI) device that gets most of it's information from the vehicle's computer system. What isnt in the vehicle's computer system is captured in the ODB-II device on-board electronics. The Artificial Intelligence (AI) software calculates weight by monitoring powertrain effort and vehicle acceleration.  The Artificial Intelligence (AI) software uses a complex torque converter model to devise the Powertrain effort. For this reason, vehicle with manual transmission that dont have a torque convert won't have full functionality. In the USA HaulGauge uses the VIN to search its database for the correct torque converter calibration.   In Australia, we have developed a simple procedure for the user to calibrate the scale utilizing a patented Machine Learning algorithm.  Acceleration is determined utilizing a triaxial accelerometer on board HaulGauge.   For the super-technical minded: when powertrain effort is high relative to vehicle acceleration, then weight has increased.



  • Measures Gross Combined Weight (GCW includes vehicle, cargo, passengers, and trailer)
  • Peace of Mind. No more guessing. Easily decide if overloaded.
  • Convenient. No longer need to drive to a weigh bridge.
  • Saves money and time. HaulGauge will display the weight within seconds of driving.
  • Safety. Knowing the maximum total weight of the trailer for a safe set up.





  • Keep hitch drawbar weight within the vehicle’s rated capacity. (called tongue weight in USA)
  • Compare drawbar weight to caravan weight to verify caravan is properly loaded.  Drawbar Weight should be around 10-15% of Gross Trailer Weight (weight of trailer and cargo).
  • Save money on expensive drawbar weight gauges
  • Convenient. No more hastle of using a bathroom scale to figure drawbar weight.
  • Safety. Proper drawbar weight is key to safe towing and trailer sway avoidance. Use HaulGauge to get it right and tow safe.
  • Peace of Mind. No more guessing. Easily decide if overloaded.

Overweight vans caught in blitz by Operation Roadhouse

More than half of caravans pulled over in police operation found to be overweight.

The spotlight has been shone on the problem of over-weight caravans with more than half the caravans pulled over in a recent police blitz in Victoria proven to be over-weight.

Part of Operation Roadhouse, the two-day exercise was conducted by VicRoads and Victoria Police in early January at the Newmerella rest stop along the Princes Highway, near Orbost in Victoria.

More than 70 caravans were weighed using portable scales, with the ball, GTM and ATM weights compared to 'stamped' ratings on the vans’ compliance plate.

Acting Sergeant Graeme Shenton cited some startling statistics, including 41 caravans (almost 60 per cent) found to be overweight in at least one category. One van was 280kg over its plated ATM rating of 2600kg, while another had a ball download of 400kg, or 120kg higher than the maximum.

Writing on the popular Caravaners Forum website, Act Sgt Shenton also noted that “most ATM offences were in the 1500kg to 2500kg size vans" with camper trailers loaded with bikes, generators, and other heavy gear among the worst offenders. 

"Most of these had max ATM around 1650 and were consistently 100kg-plus over. These were also being towed by the smallest cars, many of them sedans that did not have the capacity to tow those weights,” he said. 

No tow vehicles were weighed but he estimated at least 15 would have also been overweight in relation to the car’s GVM (gross vehicle mass) or GCM (gross combination mass).

He said many of the drivers spoken to were not aware of their vehicle being over-weight, or were unclear about the various weight ratings or how to measure them.  

“Of most concern was that most drivers had little idea of what they weighed. The fact we had 41 offenders I think was more by luck than any sort of planning by the driver.”

He said many of the caravanners were either ignorant or misguided in regards to towing regulations and safety.

“Some of those using a WDH (weight distribution hitch) believed that they allowed them to load more than the ATM into the van because it would be transferred to the car via the hitch,” he said.

A leading force behind the operation, Act Sgt Shenton said the exercise was designed to “encourage more caravan owners to think about their situation and to start to make some changes”.

“We are seeing an increasing number of single vehicle accidents and unexplained rollovers of vans,” he said. “Often these crashes can be attributed to a lack of skills, knowledge and training around the safe use of heavy caravans."