Van tyres: what the C means and why the pressures are higher

Van tyres look a lot like car tyres, but they do a harder job. A C on the sidewall tells you the tyre is built to carry a van's weight, and it usually needs more air to do it. Here's how to read the markings, set the pressures and stay within the rules.

What the C means

Look at the size on a van tyre and you'll often see a C straight after the rim size, as in 225/65 R16 C 112/110 R. Michelin says the C marking is for vans and other light commercial vehicles, and that it shows the tyre is reinforced, so it can carry heavier loads. C tyres have a higher load index than ordinary car tyres. The marking is set out in UN Regulation 54, which covers tyres for commercial vehicles.

Two load numbers: single and dual

A car tyre has one load index. A C tyre often has two, separated by a slash. In Michelin's example, 225/65 R16 C 112/110 R:

• 112 is for single fitment, with two tyres on the rear axle, as on most vans. It means up to 1,120kg per tyre.
• 110 is for dual fitment, with four tyres on the rear axle, as on vans with twin rear wheels. It means up to 1,060kg per tyre.
• R is the speed rating. A third rating in brackets, as in 107/105T (103H), is an alternative: a higher speed but a lower load.

One size can come with different load indexes: Michelin's 235/65 R16 Agilis CrossClimate is made as 115/113 or 121/119. So matching the size isn't enough. Check the load index your van maker specifies. Here's how to read the rest of the sidewall.

LT and CP

• LT stands for light truck. Regulation 54 allows LT in the same place as the C. US-standard LT tyres also carry a load range letter, such as Load Range C, which is not the same as the C after the rim size. Tire Rack notes that European C tyres are usually rated to carry more than LT tyres of the same dimensions, so check the load index before swapping one for the other.
• CP is for motorhomes: Regulation 54 describes CP tyres as designed for motor caravans.

Don't fit car tyres to a van that needs C tyres

Michelin says a van or commercial vehicle must have C tyres, and that XL or reinforced car tyres are designed for heavy passenger vehicles, not vans. The law also says a tyre mustn't be unsuitable for the use the vehicle is put to.

The MOT backs this up on bigger vans. Vans over 3,000kg and up to 3,500kg are tested as class 7, where the tester checks the tyres' load rating against the axle weights on the manufacturer's plate. A rating below the minimum is a major fault, and a tyre that can't carry the axle weight is dangerous. Here's what else the MOT checks.

Not every van needs them. Michelin says small car-sized vans such as the Citroën Berlingo and Renault Kangoo don't have to have C tyres. If your handbook doesn't ask for them, match the load index it gives.

Why van pressures are higher

A C tyre carries its extra weight through a stronger build and more air. Michelin says C tyres need inflating to a higher pressure, as recommended by the vehicle maker, so don't be surprised if your van's figures look high next to a car's.

The figures also change with the load. Michelin says a van often has several recommended pressures, depending on whether it's lightly or heavily loaded, with separate figures for front and rear. The Highway Code says tyres must be inflated to the maker's specification for the load being carried, and Michelin warns that loading up without adjusting them makes the tyres wear out much faster.

Running soft costs more than tread. Michelin says a tyre about 0.5 bar under has a shorter life, and at about 1 bar under it lists a risk of blowout, higher fuel use, changed handling and longer braking. Here's more on pressures for a full load.

Where to find your van's figures

• The label inside the driver's door, or sometimes inside the fuel flap.
• The handbook, which also gives the tyre sizes and load indexes.
• Not the sidewall. The pressure moulded on the tyre is the most it can take, not the figure to use.
• Our checker, with a caveat. Right Pressure looks up many vans by registration, but for some vans our data doesn't include pressures. If figures are missing, or anything differs from the label, the label is the authority.

How and when to check

• Check them cold, before the van has done more than a short distance. Never let air out of warm tyres, because the pressure rises as they warm up.
• At least once a month, and before every long journey, as Michelin advises. The Highway Code says weekly.
• Before a heavy job. Set each axle to the loaded figures, then back to the normal ones once you've unloaded.
• Every day if it's a work van. DVSA's daily walkaround check covers inflation, tread, deep cuts and visible cord.

Weight, payload and overloading

Every van has a maximum loaded weight, the design gross weight (or gross vehicle weight), shown on its VIN plate. GOV.UK says it includes the van, driver and passengers, fuel and load. Your payload is what's left for the load once everything else is counted, so a full crew means less room for cargo. Each axle has its own limit too, shown on the manufacturer's plate.

• Overloading is an offence under the Road Traffic Act. GOV.UK says you can be fined up to £300 or summonsed to court if your van is over its maximum permitted axle weight. Police and DVSA officers can also issue a prohibition, which stops you driving until the problem is fixed.
• Weigh it if you're not sure, at a local weighbridge, and load evenly with the heaviest items at the bottom.

Camper vans and motorhomes

Michelin recommends C tyres for camper van conversions and CP tyres for heavier motorhomes. It says CP tyres have a higher load index and a reinforced carcass, and run at higher pressures than C tyres. Above 4.5 bar (65 psi), Michelin says you need a metal valve clamp or a special high-pressure valve. Use the motorhome maker's figures, check monthly and before a long trip, and shade the tyres during long spells parked, since Michelin says UV and heat speed up ageing. Here's how to tell a tyre's age.

Tread depth

For vans up to 3,500kg, the legal minimum is 1.6mm across the central three-quarters of the tread and around the whole circumference. The same applies to zero-emission vans up to 4,250kg. GOV.UK says you can get 3 penalty points for each tyre that isn't safe and legal, and using a van in a dangerous condition can mean a fine of up to £2,500 and 3 points.

Check for the C, match the load index, and set the pressures for the load you're carrying. On a van, those three things do most of the work.