What is a tyre speed rating? Decode your tyre sidewall markings with our straightforward tyre labelling explainer
You’ve probably noticed the tyre sidewall markings on your car, but like most of us you’ve no doubt not given them much thought. However, there’s lots of useful information locked away in those numbers and letters, much of it that is useful when you’re buying new tyres. So here’s our guide to what all those what the tyre codes mean and how they can help you.
Tyre codes are labelled on the sidewalls and consist of various letters and numbers – you’ll need to decipher these to make sure your replacement choices are suitable and safe for your car.
In many respects the tyres are the most important part of the car, because they are what connects you with the road’s surface. Not only can the wrong tyres cause handling issues, they can be plain unsafe in certain conditions.
The first thing you’ll probably notice on your tyre’s sidewalls is the manufacturer and product name. Although you can ask the garage to replace your tyres like-for-like, it’s not necessarily the cheapest option.
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The rest of the tyre sidewall markings offer more in-depth information, and there’s a lot you can find out from the letters and numbers shown. As well as the vital UK/EU type approval mark, tyre labelling can tell you the size of the tyre (diameter and width), maximum speed and load ratings and even its type of construction. Crucially, they’ll also tell you when the tyre was manufactured, because unlike fine wine, rubber does not get better with age. You’ll also see stickers that give an indication of economy and noise ratings, as well as wet road grip ratings.
This is all information that should be taken into consideration when buying new tyres for your car.
How to read a tyre
There’s a range of information printed on the side of a tyre approved for use on the road. As well as the name of the tyre manufacturer, you’ll also find digits relating to its size and speed rating.
On the side of a tyre – also called the sidewall – you’ll find a series of digits. We’ll use the following example: 215 45 R16 91 W E4.
The first number – 215 in this example – shows the width of the tyre in millimetres.
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The second number – 45 – shows the height of the sidewall as a percentage of the tyres’ width. In this example, the tyre’s sidewall height is 45% of the 215mm width.
The letter R refers to the tyre’s construction. You’ll rarely see a letter other than R, as it refers to a radial tyre. This is the most common type of car tyre, and it uses steel and kevlar belts to help the tyre maintain its shape at higher speeds.
The next number – in this case 16 – refers to the size of the wheel it will fit. So our sample tyre will fit a wheel of 16 inches in diameter.
The next number – here it’s 91 – shows the tyre’s load rating, but confusingly this doesn’t relate to the actual weight the tyre is able to carry. In this instance, 91 denotes the ability of the tyre to carry 615kg. Load ratings range incrementally from 62 (265kg) to 126 (1,700kg).
The following letter – W – is the tyre’s speed rating. You can find out more about this in the table below.
The final pair of digits – E4 – is an approval mark showing the tyre has been tested and approved by the European regulatory authorities. You should always check your tyres carry this approval.
What is a tyre speed rating?
The tyre’s speed rating represents the top speed that the tyre is capable of maintaining. A letter that appears on your tyre’s sidewall illustrates the rating (see example above).
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It’s essential that you choose a tyre capable of travelling at speeds in excess of your car’s maximum speed – even though every tyre is capable of maintaining speeds of more than 70mph.
You could find your car insurance invalidated by using tyres with a lower speed rating than appropriate for your car.
How do I find the correct rating for my car?
The tyre speed ratings for your car will be listed in your vehicle’s owner’s manual. Alternatively, check with your main dealer.
Tyre speed rating codes
|Speed rating||Top speed|
OE tyre markings
Some tyres are specifically designed for certain car manufacturers. OEM (which stands for Original Equipment Manufacturer) tyre markings are labelled on many tyres to show which car brand a tyre was specifically engineered for. The following table shows which markings correspond to which manufacturers:
Original Equipment Manufacturer
AO | AOE | RO1
Audi Original | Audi Original Extended (ROF) | Audi Quattro
BMW & Mercedes
“Star” marking & Mercedes Original (Extended)
K1, K2, K3
Jaguar & Land Rover
Jaguar Land Rover
Lotus Exige S
Maserati Genuine Tires
Maserati & Jaguar
Maserati Genuine Tires & Jaguar
MOE | MO | MO1
Mercedes Original Extended (ROF) | Mercedes Original | Mercedes Original (for AMG models)
Nissan GT-R Nismo
N0, N1, N2, N3, N4, N5, N6
T0, T1, T2,…
New tyre stickers
Every new tyre sold in Europe comes with a label that provides information on wet grip, the tyre’s impact on fuel economy and the noise it generates, here’s how to decipher the codes:
The first chart has a scale of A to G that shows fuel efficiency, where A is best. The difference between grade A and G can be up to 7.5 per cent, according to European Commission research. This chart measures rolling resistance – effectively the more energy that’s needed to turn the wheel, the less the efficiency.
The second chart uses the same A-G rating to show the amount of grip the tyre can generate on a wet road. The test used to evaluate wet grip is a braking test from 50mph, and the difference in stopping distance between each grade is between one and two car lengths.
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Therefore the difference between the stopping distance of an A-rated tyre and a G-rated one could be 18 metres. If a tyre has a good fuel efficiency rating, then its wet grip score may be poor, because by reducing rolling resistance, wet grip is reduced, so you’ll need to strike a balance between decent performance in both regards.
The third chart illustrates the external noise generated by the tyre when it’s travelling at 50mph. The noise is expressed in decibels (dB).
There’s also a symbol that looks a little like a wifi sign. One black arc means the tyre will be compliant with future legal limits, three black arcs represents the weakest performance and sits somewhere between the current maximum and forthcoming lower limits.
These regulations will apply to most tyres, but some types of tyre for cars, light commercial vehicles and trucks are excluded, including:
• Temporary tyres and space saver spares
• Professional off-road or racing tyres
• Studded tyres – if the metal studs are fitted
• Tyres intended for cars registered before 1 October 1990
• Tyres with a speed rating of less than 50mph
• Tyres with a rim diameter of less than 254mm or more than 635mm
If you’re looking for new tyres then why not check out our guide to the best all-season tyres?
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