When it comes to towing a caravan or trailer, it is important to understand tyre load ratings to ensure you stay safe and road-ready!
In this guide, we’ll explain what tyre load ratings are, why they are important, how to read the tyre load index and how to keep your tyres in optimal condition.
Whether you’re setting out on your first trip or a seasoned caravaner, this guide will help you to steer clear of load-related troubles!
Tyre load ratings are numerical values that represent the maximum weight a tyre can carry when in optimal condition. They are usually printed on the tyre sidewall, but you may also find them on the manufacturer’s website or your vehicle owner’s manual.
To work out the maximum weight your tyre can support, note down the number on your sidewall and check this against the Tyre Load Index chart.
The tyre load index chart is a reference chart that matches each load index number to its corresponding maximum weight capacity in kilograms.
Though it might seem daunting at first, it’s simple to use! The amber columns list the “load indexes” that you will find on the sidewall of your tyre. The white columns show the corresponding maximum load in kilograms.
So, if the load index on the sidewall of your tyre reads “79”, the maximum weight your tyre can carry is “437kg.”
You can then multiply the load rating of each tyre by the number of tyres on your vehicle to find the total load capacity.
For example, “437kg x 4 tyres = 1748kg.”
1748kg is the total load capacity.
The tyre load index chart is based on tyres in good condition and in temperate weather. Which means that your load rating is only as good as your tyre maintenance!
While it’s important to be aware of the overall condition of your tyres including your tread depth, your tyre pressure is particularly important when considering tyre load ratings.
If your tyre pressure is too low, your vehicle will not be able to carry the weight indicated on the tyre load index. Meanwhile, if your tyres are overinflated, they will not provide enough grip on the road. It is particularly important for those carrying heavy loads, such as caravans and trailers, to ensure their tyres are inflated to the recommended levels to maximise the effectiveness of load ratings.
The tyre load index chart is based on tyres in good condition and in temperate weather. Which means that your load rating is only as good as your tyre maintenance!
While it’s important to be aware of the overall condition of your tyres including your tread depth, your tyre pressure is particularly important when considering tyre load ratings.
If your tyre pressure is too low, your vehicle will not be able to carry the weight indicated on the tyre load index. Meanwhile, if your tyres are overinflated, they will not provide enough grip on the road. It is particularly important for those carrying heavy loads, such as caravans and trailers, to ensure their tyres are inflated to the recommended levels to maximise the effectiveness of load ratings.
We have created a caravan pressure calculator to help you determine adequate pressures, but you can also use the table provided below. Our calculator takes into account the weight of the load, number of tyres and tyre size to ensure accuracy.
Did you know, when pulling heavy loads, it’s important to ensure that the tyre pressure is higher in the back wheels of the towing vehicle. As a general rule of thumb, increasing the pressure by 4 to 7 PSI (0.3 to 0.4 bar).
You can use the following caravan/trailer tyre pressure chart to check what the recommended tyre pressure is for each load index and type of tyre.
It’s worth noting here, that instead of listing a “per tyre” maximum weight capacity, the table lists a “per axle” maximum weight capacity – assuming there are only two tyres per axle.
So, if the load index on the sidewall of your standard tyre reads “86”, the maximum recommended weight your axle can carry is “954kg.”
If you are towing a two-axle caravan or trailer, your total maximum capacity would be 1908kg.
And to safely support this load, your tyre will need to be inflated to 36 PSI or 2.4 BAR.
Particularly when towing caravans and trailers, it is advisable to avoid continuous operation at or approaching the tyres’ maximum load capacity. In fact, it is recommended that the maximum vehicle load does not exceed 90% of the combined tyre load capacity. Column three outlines this recommended maximum axle load.
The last column in “red” highlights the axle loads in excess of 90% and up to the maximum permitted for the tyres.
Stay safe and road-ready with our Guide to Caravan Tyre Safety!
Download our handy guide to Caravan tyre safety (PDF, 1.7Mb)
