This calculator is designed to provide you with a complete towing report including standard reference weights and tyre pressures for both your tow vehicle and trailer combination.

To use this calculator, you must have completed a four point weight recording at a weigh bridge or scale facility (see below).

We recommend that both the tow vehicle and trailer are fully loaded as they would be when you head away on holiday, this includes water tanks (full or empty depending on your usual preference) fuel tanks, family and pets etc.

How to complete a four point weight recording;

1. With the trailer still hitched to the tow vehicle, drive only the front wheels of the tow vehicle onto the weigh bridge and record the weight. This is your front axle load and we will use it to calculate your ideal front tyre pressures (note; better if the front wheels are as far onto the bridge as possible but with the rear wheels still off the platform)
2. Next, drive the whole vehicle onto the weigh bridge but stop with the trailer wheels still off the platform. Record this weight, it is your Gross Vehicle Mass (GVM)
3. Next, you will drive forward until the tow vehicle is completely off the weigh bridge, the trailer is still connected to the vehicle and only the trailer wheels are on the weigh bridge. Record this weight, it is your Gross Trailer Mass (GTM) (note; it is helpful when positioning for this step, if you ensure that the vehicles rear wheels are off the weigh bridge but the trailer drawbar is still over the weigh bridge. It will save you moving again for the next step)
4. Finally, lower the trailer jockey wheel onto the weigh bridge, completely lift the tow coupling off the vehicles tow bar so that you can record the total weight of the trailer without the vehicle. This is your Aggregate Trailer Mass (ATM)
5. Don’t forget to re-hitch the trailer to your vehicle and check all safety connections before driving off.

Now that you have your 4 weights, you should also record the load ratings from the tyre sidewalls of both your tow vehicle and your trailer (see photo below)

Notes on tyre load ratings; not all tyres are the same, the load rating on your trailer tyres may be quite different to your tow vehicle. If your trailer has dual axles, you should use the load ratings for DUAL. For single axle trailers and your tow vehicle, use the load rating for SINGLE (see photo above for clarification).

That’s it, now simply enter your records into the calculator to see tyre pressures calculated specifically for your towing combination. If you would like a full towing report then you can enter your Name and Email then click the “Email Full Report” button to receive a complete breakdown of your towing weights and tyre pressures.

Feel free to leave comments or questions below.