How to read your tyre size, load index and date code

A tyre size such as 225/50R18 means a tyre 225 mm wide, with a sidewall height that is 50% of that width, of radial construction, for an 18 inch rim. The code after it, such as 95V, gives the load index and speed rating, and the last four digits of the DOT code tell you when the tyre was made.

All of this is moulded into the sidewall. Here is how to read it, using 225/50R18 95V as the example.

The size: 225/50R18

225 is the width. This is the nominal width of the tyre in millimetres.

50 is the aspect ratio. The sidewall height is 50% of the width. On this tyre that works out at about 112 mm. A lower number means a shorter sidewall. Tyres with a low ratio are often called low-profile, though there is no single agreed cut-off.

R is the construction. R means radial, the standard build for modern car tyres.

18 is the rim diameter. This is measured in inches. The tyre must match the rim exactly.

Some sizes carry an extra letter. P marks a passenger car tyre, LT a light truck tyre, C a van tyre and T a temporary spare.

The load index: 95

The load index is a code for the maximum load one tyre can carry. It is a code, so 95 does not mean 95 kg. You look it up on a standard chart. Michelin's chart gives these values:

• 91 is 615 kg
• 94 is 670 kg
• 95 is 690 kg
• 97 is 730 kg
• 100 is 800 kg

That figure is per tyre, at the correct pressure.

The speed rating: V

The letter after the load index is the maximum speed the tyre is rated to sustain. Common ratings for cars are:

• H is 210 km/h
• V is 240 km/h
• W is 270 km/h
• Y is 300 km/h

The rating is a limit for the tyre. The road speed limit still applies. Michelin says you must not fit a tyre with a lower speed rating than the vehicle maker recommends, with an exception for some winter tyres that does not apply on Malaysian and Singapore roads. A higher rating is acceptable. The same goes for load: a tyre of the same size with a higher load index is compatible, while a lower one should be avoided.

The DOT date code

Look for the letters DOT followed by a string of characters. The last four digits are the production date. The first two are the week and the last two are the year.

So a tyre marked 2524 was made in week 25 of 2024.

The date code appears on only one sidewall, so it may be facing inwards on your car. If you cannot see it, check the other side of the tyre or ask a tyre shop to look.

Tyre age matters because rubber deteriorates over time. Michelin's Malaysian site gives five years as a general replacement recommendation and ten years as the maximum. Our guide on why tyres burst has more on ageing.

Other markings you may see

Maximum pressure. This is the most the tyre can hold. It is different from the pressure your car needs. Use the figure on the label in the driver's door sill, inside the fuel cap or in the owner's manual.

Tread wear indicators. These are small raised bars in the main grooves, 1.6 mm high. When the tread has worn down to their level, the tyre needs replacing.

M+S. This shows some capability in mud and snow.

E mark. An E followed by a number is an approval mark, with the number standing for a country.

Where to find the right size for your car

The tyres on your car may not be the correct ones if a previous owner changed them. Check the size listed on the door label or in the owner's manual, and compare it with what is on the car. If they differ, ask a tyre professional before you buy.

Keep the full marking when you buy tyres. Two tyres can share the size 225/50R18 and still differ in load index and speed rating.

Why your tyre size matters for a Multiband

We ask for your tyre size when you request a quote, because it decides which band you need. The Tyron Multiband fits normal tyres on 14 to 22 inch wheels. Low-profile tyres, with an aspect ratio of 45 or below, need a fitment check first. We do that for you. Have a look at your sidewall, then send us your size for a quote.