Choosing the right tyres — and running them at the right pressures is one of the most important parts of safe and comfortable towing. Tyres aren’t just “black round things”, their construction, load rating, and inflation determine how well they carry the load of your car & caravan, cope with rough roads, and resist punctures.

In this article, we’ll look at tyre markings, construction types, and practical rules for setting the right pressures and purchasing the right tyres, with a focus on caravan use.

Understanding Tyre Markings

Below is a list of what all the markings on my tyre mean. As a end user some of it is important, some of the markings are for manufactures and supplier networks. I also list some other markings you may see.

Have a good look at the photos, click on each one to see the markings clearly. The parts circled in red are the important bits for this article.

TIP: Use your phone to take a picture of the tyre markings, it will be a lot easier to read when everything is up the right way.

• LT = Light Truck construction (built for heavy loads).
  • Some other markings you may see
    • Blank or P = Passenger
    • C = Commercial
    • T = Temporary
• 285 = Tyre width in mm.
• 65 = Aspect ratio (sidewall height = 65% of width).
• R18 = Radial construction, fits 18” rim.
• 125/122 = Load index (1650 kg single / 1500 kg dual), You get the Kg rating from the table below.

For most, if not all caravans it is the first number (125) that is used

• Q = Speed rating 160 km/h max, LT tyres, off-road & caravan tyres
  • Other Markings you may see
    • R = 170 km/h max, Some LT/van tyres
    • S = 180 km/h max, Older passenger or SUV tyres
    • T = 190 km/h max, Family cars, SUVs
    • H = 210 km/h max, Most modern passenger tyres in AU
    • V = 240 km/h max, Performance sedans & sports cars
• 10PR / Load Range E = Strong casing, 10-ply rated equivalent. Heavy duty, off-road caravans, 4WD.
  • Other markings you may see
    • 6PR / Load Range C = light duty (small vans, trailers)
    • 8PR / Load Range D = medium duty (vans, lighter caravans)
    • 12PR / Load Range F = extra heavy duty (small trucks)
    • 14–16PR / Load Range G–H = heavy trucks, buses

The tyre load range and max tyre pressure are related because heavy duty tyres are expected to carry heavy loads.

• At 550 kPa (80 psi) Cold The maximum load ratings are only valid if the tyre is inflated to 550 kPa = 80 psi, measured when the tyre is cold (before driving heats it up).
• Construction note at the bottom Sidewall: Polyester 2 Tread: Polyester 2 + Steel 2 + Nylon 1
  This describes the internal ply materials. Strong polyester carcass with steel belts and a nylon overlay for reinforcement.
• E4 0041459 This is an ECE type approval mark (European safety certification). “E4” = the Netherlands was the testing authority. The number is the approval code for this specific tyre model.
• OW: 11.50 Refers to the measuring rim width (11.5 inches) used when determining the tyre’s size specifications.
• OD: 33 tyre’s overall outside diameter 33 inches.
• DOT Department of Transportation certification (U.S. standard, used globally to indicate compliance).
• 1FB Plant code — identifies the factory where the tyre was manufactured.
• BWP A0 Internal manufacturer and tyre line codes — tells Yokohama exactly which design/specification this tyre belongs to.
• 1625 Date code — week 16 of 2025. That means this tyre was manufactured in April 2025.

What Tyre do I need?

The load rating is the main thing to watch out for, followed by the construction type. The tyre must match the rims you have size wise.

Combined Rig	Typical Combined Setup	Recommended Tyre	Why
Light Touring Rig	Small SUV (GVM < 2.8T) + Caravan ≤ 2.4T ATM	8PR (Load Range D)	Adequate strength for lighter rigs, comfortable ride, cost effective
Touring Rig	Medium/Heavy SUV or dual-cab ute (GVM 2.8–3.5T) + Caravan 2.5–3.0T+ ATM	10PR (Load Range E)	Strong sidewalls, handles heavier loads, safer on gravel
Outback Touring Rig	Any tow vehicle + caravan/camper used on corrugations/remote tracks	10PR (Load Range E)	Extra puncture resistance and durability, even if the load is lighter
Heavy-Duty Rig	Light truck (GVM > 3.5T) + Caravan/Gooseneck > 3.5T ATM	12PR (Load Range F) or higher	Necessary for very heavy combinations, truck-level durability

What is Load Index?

You may come across this term, basically it is a percentage of how close to the maximum load the tyre is.

The load rating of the tyre must meet or exceed the vehicle’s Gross Trailer Mass (GTM). The GTM is the total weight of your caravan when hitched.

Not sure what GTM, ATM, GVM, blah blah blah means? Have a look at this article Towing Terms Made Simple

Actual Load ÷ Max Load x 100 = Load Index

Example

e.g 1400 Kg ÷ 1650 Kg x 100 = 84%

Load %	Meaning	Risk Level
≤ 85%	Ideal — long tyre life, lower heat	Safe
86–90%	Typical for loaded caravans, single axle	Acceptable
91–100%	Near max — monitor heat & pressure carefully	High risk if prolonged

Most manufacturers recommend not going over 90% , you want some safety margin allowing for occasional extra loading on one side due to shifting loads.

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Tyre Life: Wear vs Age

• Car tyres: Typically wear out at around 60,000 km in 3–5 years.
• Caravan tyres: Rarely wear out. Instead, they “age out” after 5–7 years due to UV, ozone, and static load.

Signs of ageing include:

• Sidewall cracks (“weather checking”).
• Tread surface cracking.
• Bulges, blisters, or deformation.
• Rubber turning grey and chalky.
• Flat spots
• Rubber going hard, will look almost polished. These tyres are bad on wet roads, poor grip.

Rule of thumb: Replace caravan tyres by 6 – 7 years maximum, even if the tread looks new. This will be especially true if considering outback, off-road driving, and the Load Index is above 85%.

This is a general recommendation from most manufactures, there is no hard and fast rule here as every tyre will be used in different conditions, it is up to you to use your judgement, or seek professional advice from a tyre shop, caravan repair shop.

Also keep an eye on the Wheel Alignment, get it checked and use this hack to keep an eye on it.

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Setting Tyre Pressures

Now here is some more maths. For caravans, without getting everything weighed, use the GTM figure, the reality is you won’t be far from this.

For better accuracy, you will need to get yourself weighed at a weigh bridge, or get a mobile weigh guy to help.

This is for highway use.

Our Caravan specs as an example:

• GTM = 2500 Kg (from the compliance plate)
• Max tyre load from tyre= 125 ( 1650 Kg, form load table above)
• Max tyre pressure 80psi (from the tyre)
• single axle (2 wheels)

Formulae

GTM (Kg) ÷ 2 (wheels) = Load per Tyre in Kg

e.g 2500 Kg ÷ 2 = 1250Kg

Actual load ÷ Max Load X max pressure = recommended tyre psi

e.g 1250 ÷ 1650 x 80 = 60 psi (cold)

This is a good suggested starting point for me with these tyres, for single axle off-road caravans I would think most people will be about the same.

Example – Tandem Caravan specs

Same thing, except with 4 wheels.

• GTM: 3200 kg (from the compliance plate)
• Max tyre load from tyre= 125 (1650 Kg, from load table above)
• Max tyre pressure 80 psi (from the tyre)
• Twin axle (4 wheels)

3200 kg ÷ 4 wheels = 800 Kg

800 Kg ÷ 1650 Kg X 80 psi = 39 psi

For a caravan with these specs, 39 psi cold would be a good starting place.

Don’t have a calculator handy, try the calculator below to see what your tyre pressures should be and the Load Index ratio.

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The 4–8 PSI Rule

A practical way to check pressures on the road:

• After driving an hour, hot pressures should have risen by 4–8 psi.
• More than 10 psi → underinflated, more air needed in tyre.
• Less than 4 psi → overinflated, remove air from tyre.

This works well for caravans because loads change (water tanks full/empty, gear added), also true for heavy Utes, large SUV's, specifically the rear tyres.

Also, bear in mind when starting with high tyre pressures each 1 psi represents a smaller % change, so the total rise might be 6–8 psi instead of the traditional 4–6 psi, which would be more applicable to normal tyre pressures for a car, or a tandem caravan.

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Gravel Roads: The 30 PSI Rule

Many experienced travellers deflate to ~28–32 psi cold on corrugated gravel roads.

• Why: Softer tyres cushion the ride, protect suspension, and reduce vibration damage.
• Caveat: Keep speeds down (60–80 km/h). Low pressures at highway speed = overheating and tyre failure risk.

This approach is much safer than the old “go faster and skim over the corrugations” trick. Just because the tow vehicle feels smoother at 90 km/h doesn’t mean the caravan is. In fact, the van’s suspension and chassis may be copping a flogging at that speed.

Personally, I would be reluctant to go any lower as you will risk the tyre getting pinched by a large rock. Punctures/blowouts are not fun.

Sand Driving

Sand driving/towing, it is the same for your caravan as it is for your car, approximately 18 psi for the car, and 20 psi for the caravan. This is to increase the foot print of each tyre giving you more traction, and also to stop the tyres digging into the sand. Speed to be kept way down i.e about 30 - 40 Kph.

If you come across hard/firm sand, then for a short distance you can go a bit faster, caution will be needed as the tyres can overheat quickly.

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Choosing the Right Tyre Brand

When it comes to caravan tyres, it’s worth sticking with reputable, well-established brands — especially for heavy or long-distance touring. While budget tyres might look tempting, quality construction, heat resistance, and consistent load testing make a big difference to safety and reliability.

This is especially important if considering gravel, corrugated off-road driving, think Oodnadatta, Gibb river rd, etc.

Major, Proven Brands in Australia

These manufacturers have strong reputations for durability and wide national support:

• Michelin / BF Goodrich – premium build, excellent heat resistance, and good off-road performance.
• Bridgestone / Firestone – long-running Australian presence, reliable dealer network.
• Goodyear / Dunlop – solid mix of on-road comfort and load handling.
• Toyo / Yokohama / Falken – quality Japanese brands with a good balance of cost and strength.
• Maxxis / Hankook – mid-priced but respected for their LT and A/T ranges (popular with caravanners).
• Cooper / Mickey Thompson – very popular in the off-road touring scene for strong casings and long tread life.

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Practical Tips

• Always check the “LT” (Light Truck) marking for heavy caravans and tow vehicles.
• Confirm that the load index and pressure rating match or exceed your caravan’s ATM. For purchasing tyres for you caravan, we use ATM figures as this is the theoretical maximum loading.
• Choose a brand with a national service network — handy for warranty and replacements when you’re thousands of kilometres from home.
• Avoid “no-name imports” — their load and speed ratings are often optimistic or inconsistent.

Good Rule of Thumb

If the tyre brand is available nationwide through major outlets (Bob Jane, Bridgestone, Tyrepower, Beaurepaires, etc.), it’s likely been tested for Australian conditions.

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Conclusion

For caravanners, tyres are the most critical safety component.

• Learn to read the sidewall markings.
• Understand that caravan tyres age out before they wear out.
• Use the formula and the 4–8 psi rule to set correct pressures.
• On gravel, corrugated tracks, air down to 30 psi and slow down — protect your tyres, suspension, and caravan.

Getting tyre pressures and construction right is the difference between a safe, smooth trip and a roadside headache.

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Disclaimer:

This article is meant as guidance only.  If you have any questions, or are unsure what your tyre pressures should be, your caravan manufacturer or local dealership will be able to advise you fully. If you have any doubts about the suitability or the condition of your caravan’s tyres please consult a tyre specialist. Remember any tyre defects that you can be prosecuted for on your towing vehicle, also apply to your caravan tyres when towing your caravan on public roads.

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