The Complete Caravan Tyre Pressure Maintenance Guide

If you are an avid caravanner (or ready to become one), you’ll appreciate that caravan tyres are the only point of contact between your caravan and the road, making it essential for safety that regular checks are carried out. This includes being able to brake, steer, and accelerate safely. Caravan tyre pressure can also affect fuel efficiency, the life of your tyres, and the smoothness of your journey.

The consequences of incorrect caravan tyre pressures

Driving with under-inflated or over-inflated tyres can have serious consequences, including:

Under-inflated tyres

Reduced fuel efficiency. Under-inflated tyres create more rolling resistance, meaning your vehicle must work harder and it will burn more fuel.
Poor handling. Your car may become less responsive, making it harder to steer and control.
Increased risk of a blowout. Under-inflated tyres are more prone to damage and can lead to sudden blowouts, especially at high speeds.

Over-inflated tyres

Reduced traction. Over-inflated tyres have a smaller contact patch with the road, reducing grip and stability.
Uneven tyre wear. The centre of the tyre wears faster, leading to premature replacement.
Uncomfortable ride. Overinflated tyres can make your ride harsher, which can affect comfort.

How to check tyre pressure

Before each trip, you should carefully check your tyres’ condition and pressure.

Tyre condition

It is recommended that your tyres be replaced every five years or every 10,000km, depending on which comes first. Even if your caravan is not being towed regularly, the wheels can still be subject to wear and tear from external factors such as sun exposure. Keeping an eye on your tread depth is crucial for your safety, as it impacts all areas of driving, particularly when you are trying to stop. It is recommended that your tread depth isn’t past 1.6mm. If you’re not sure of the age of your tyres, it is usually stamped on the tyre’s sidewall.

Tyre pressure

Your vehicle’s recommended tyre pressure PSI (which stands for pounds-per-square-inch) can be found in your vehicle’s manual, on the tyre itself, and/or on your caravan’s VIN plate, and this should not be exceeded. However, the recommended tyre pressure is a guide only, as factors like unusual driving conditions on unsealed roads and tracks with mud, sand, and sharp stones may require an alteration of tyre pressure. A rough guide recommended by experts is:

Bitumen touring. Typically, on bitumen, you travel faster for longer, so your tyres heat up more. It is recommended that you set your tyres at the upper end of their recommended pressure range, which, in most vehicles, is around 45 PSI. The higher pressures will decrease your rolling resistance (friction), meaning better fuel consumption, and also open up the tread. This means they will drain water better in wet conditions and give you better traction and braking grip.
Formed, unsealed roads. Typically, pressures in the 30-35 PSI range work best, as they allow the tyre tread to spread better and give you better grip, but only if you reduce your speed simultaneously. A maximum cruising speed of 65-70 km/h is best, which will allow you to ride the corrugations better while reducing the stone peppering on the front of your caravan. Always pay particular attention to the pressure of the rear tyres of your tow vehicle, as the ball load will drive them harder into loose stones that may cause punctures. When you hit the bitumen again, raise the pressures again, as higher towing speeds will build up heat quickly and could lead to tyre carcass failure.
Loose surfaces like sand. On very loose surfaces like sand, drop your tyres to 15-18 PSI to get maximum ‘balloon’ from your tyres and distribute their load better. Avoid turning sharply at these low pressures to prevent the tyres from breaking their bead sealing on the rim and releasing air.

Caravan tyre pressure chart

You can also undertake more specific caravan tyre pressure calculations, but first, you need to decipher the code on the tyre sidewall. This is what a typical code looks like: 205 / 65 R 15 94 H.

The first part of the number refers to the tread width, which is 205mm wide in this example.
The second number is the Aspect Ratio, which means the tyre wall height is 65 per cent of the tread width.
The following letter (R) is the tyre construction, which, in this case, is Radial.
The following number (15) is the rim diameter in inches.
The following number (94) is the load rating. The load rating for the tyre can range from 60 to 130, equating to a maximum load per tyre of 250 kg to 1900 kg. The first thing to check is that the tyres are rated for your caravan’s gross trailer mass (GTM). As a result, we need to know the load index ratings.
Finally, the last letter (H) is the speed rating for the tyre.

Source: RV Daily

From the table above, you can cross-reference the load rating code number to the maximum permissible load the tyre is rated for. So, from the chart above, we can see that a load index of 94 means the maximum load for the tyre is 670kg. However, this is the load for one tyre. So, on a single axle, those two tyres could carry a maximum load of 1340kg. However, the tyre industry’s recommendation is you should never exceed 90 per cent of the tyre’s load index. So, in this case, the maximum axle weight would be 1251kg.

You also need to know the Maximum Tyre Inflation Pressure and Load from your caravan tyre. This is usually located in smaller text on the sidewall below the tyre data. It will say something like Maximum Load 720 kg, Maximum Pressure 52 PSI, and the pressure might be given in BAR. Once you have your caravan’s Gross Trailer Mass (GTM) and the maximum pressure for your tyre, you can work out the correct tyre pressure.

Calculating specific caravan tyre pressure

Take the figure for the maximum pressure for the tyre and divide it by the maximum weight from the table above. Now multiply this figure by the actual load you will put on the tyre — so half the GTM for a single-axle caravan or a quarter of the GTM for a twin-axle caravan. The resulting figure should be the correct inflation pressure for each tyre. Here are some examples that may help with your calculations.

Single-axle caravan

Caravan tyre details: 205 / 65 R 15 94 H – Maximum Inflation Pressure 60 PSI
Weight of caravan: 1200kg
Calculation: 60 / 670 = 0.08955 (the maximum pressure for the tyre divided by the load rating) 0.08955 x (1200 / 2) = 53.7 PSI (inflation factor times half the weight of the caravan)
So, the correct tyre pressure is 54 PSI.
*Note: / stands for divide by.

Twin-axle caravan

Caravan tyre details: 205 / 65 R 15 94 H – Maximum Inflation Pressure 60 PSI
Weight of caravan: 1800kg
Calculation: 60 / 670 = 0.08955 (the maximum pressure for the tyre divided by the load rating) 0.08955 x (1800 / 4) = 40.29 PSI (inflation factor times one-quarter of the weight of the caravan)
So, the correct tyre pressure is 41 PSI.
* Note: The / symbol stands for divide by.

How to check your caravan tyre pressure

Once you know the required caravan tyre pressure, unscrew the valve cap from the tyre’s valve stem.
Place the pressure gauge onto the valve stem and press firmly until you hear a hissing sound. This indicates that the gauge is reading the pressure. Check the reading against the recommended PSI. If it’s low, add air. If it’s high, release some air until it matches the recommended pressure.
Repeat for all of your caravan’s tyres, as rear tyre pressure when towing a caravan is important, too.
Don’t forget the spare tyre. It’s often overlooked but is equally important.

Other tips for measuring caravan tyre pressure

Factor in the ‘heat’ of your van. The inflation pressure of a hot caravan tyre is usually about 4 PSI higher than when it’s cold. If you check your tyre pressures when hot and they are more than 4 PSI higher, this means the cold inflation pressure was too low. If the hot inflation pressure is less than 4 PSI difference from the cold pressure, then the cold pressure was too high. It’s recommended that you check the tyre pressure when your vehicle is cold.
Invest in a reliable pressure gauge. Digital gauges are easy to read and provide accurate measurements.
Make sure you have a safe load capacity. Every tyre manufacturer will have a load capacity index rating you can check to ensure you stay within the tyre’s legal load limits.
Load your caravan evenly. A poorly loaded caravan can impact your tyres. An overloaded van at the front or back can tip, and a van loaded too much on one side can cause imbalance and uneven wear on the tyres.

How often should you check caravan tyre pressure?

Check regularly. It is recommended that you check the pressure of your tyres at least once a month and always before long trips.
Take note of the temperature. Tyre pressure can fluctuate with temperature changes, so check more frequently during extreme weather.
Pay attention to warning lights. Many modern vehicles have a tyre-pressure monitoring system. If the TPMS warning light comes on, check your tyre pressure immediately.
Regularly inspect tyres for damage. This includes examining your tyres for punctures, cuts, or other damage that could affect pressure.

For expert advice on how to optimise your caravan’s tyre pressure while on the road, contact your local dealership today.