Tyre Ratings Guide
If you have ever found yourself needing a new set of tyres and felt lost, overwhelmed and intimidated by the whole process - don't worry, you're not alone. Choosing new tyres can be a daunting task. There are so many choices and so much information to analyze that it can soon get confusing.
Tyroola has made buying tyres less complex, reducing the process to a few steps -
1. Check your tyre sidewall for details on your current tyre; take a pic of the numbers too for future reference.
2. If you have a second-hand car, make sure that the existing tyres installed are within the legal limits
3. Input the numbers or the Tyre ratings found on your tyre's sidewall here:
Tyre ratings come in very handy when it is time to get new tyres. It helps determine which tyre you need - or best matches your vehicle and driving habits. Similar to the nutrition guide or ingredient list found on every package of food at the supermarket, Tyre ratings help us determine what the qualities - even strengths and limitation - are of each tyre.
Tyre ratings can tell us how fast a tyre can go, how much weight it can carry, what kind of terrain it is for and so much more.
What do Tyre Ratings actually rate?
In a nutshell, Tyre ratings consist of INFORMATION about the tyre.
What information exactly? Well, surprisingly a lot of info. Tyre ratings rate or identify the following characteristics:
1. Vehicle Classification - what kind of vehicle is it intended for?
2. Weather - what kind of weather can it drive-in?
3. Fuel Efficiency - what is your expected fuel consumption?
4. Wet Grip - does it handle well in wet road conditions?
5. Noise - is it a noisy or a quiet tyre?
6. Size - this is a group of 3 measurements?
7. Load Rating - what is the maximum weight each tyre can carry?
8. Speed Rating - how fast can the tyre go?
9. Terrain - where is the best place to drive the tyre?
Tyre Ratings in Different Continents
Tyre Ratings differ slightly depending on the continent.
Here in Australia, the tyre ratings we follow only include tyre load and tyre speed indexes, in addition to what already comes standard on the tyre code (vehicle classification and tyre size). Tyres imported from the EU or the USA will include their preferred rating systems along with what is required in Australia. The Tyre and Rim Association of Australia (TRAA) is the Australian tyre governing body that manages tyre standards requirements and compliance across the country.
In the USA, tyre rating standards are known as The Uniform Tyre Quality Grade (UTQG), ratings. They include ratings for Treadwear, Traction and Temperature Resistance. The Tyre and Rim Association (TRA), is the US trade organization that determines and administers tyre standards across the country.
Meanwhile, in Europe, they follow another set of ratings. The EU's tyre labelling regulations include ratings for fuel-efficiency or rolling resistance, wet Grip or braking performance and noise emission or exterior noise. An A to G grading system is applied to the Fuel Efficiency and Wet Grip ratings, with an A being the highest score. As for the Noise rating, it is graded by a decibel reading. The European Tyre and Rim Technical Organisation (ETRTO) determines and administers tyre standards throughout the continent.
How do I find the Tyre Rating of my existing tyres?
The tyre rating for your particular set of tyres can be found in several places.
You can check the tyre itself. On every tyre's sidewall, there is a series of letters and numbers called the tyre code. Most of the different tyre ratings are included in this code. You can find it in your vehicle's manual as well as in your car itself, on a plate or sticker on the door jamb or frame on the driver's side.
Understanding the tyre code
Here we will give a tutorial on how to read - or decipher - the tyre code found on your tyre's sidewall.
To understand the size, dimensions and limitations of your tyre, you have to refer to an alphanumeric tyre code moulded into the sidewall rubber of your tyre.
This coding system has expanded over the years with added ratings for properties like traction, treadwear, and temperature resistance, for example.
1st Measurement: Letter
This code is established by the International Organisation of Standardisation (IOS). The tyre code usually begins with a letter denoting the vehicle class the tyre is suited for.
P: Passenger Car
LT: Light Truck
ST: Special Trailer
T: Temporary (restricted usage for 'space-saver' spare wheels)
2nd Measurement: 3-digit number
This is the measure of the width of the tyre in millimetres. It is measured from both the outer edges of each sidewall of a tyre. So, it is not just the width of the footprint of the tyre.
A slash (/) appears to separate the second measurement from the third.
3rd Measurement: 2 to 3-digit number
The 'aspect ratio' of the sidewall height is a percentage of the width of the tyre. If the information is omitted, it is assumed to be 82%.
An optional letter indicates the construction of the carcass fabric:
B: bias belt (where the sidewalls are the same material as the tread, leading to a rigid ride)
if omitted, then it is a cross-ply tyre
4th Measurement: 1 to 2-digit number
This measurement is of the diameter of the wheel that the tyre is designed to fit. The diameter is measured in inches. Though there is also the rare exception of metric-diameter tyres which are again in millimetres. The size of the wheel diameter is not strictly restricted to whole inch measurements either, as there are standard truck wheel diameters of 22.5 inches.
5th Measurement: 2 to 3-digit number
This is the Load Index rating. This rating determines the load capacity or maximum weight a tyre can carry.
6th Measurement: 1 to 2-digit/letter combination
This is the Speed Rating. This rating determines the maximum speed tolerance of the tyre.
Why are tyre ratings important?
Understanding all the information on your tyres- as reflected in its tyre ratings - will help you make the critical decision in choosing a new set of tyres.
Tyre ratings hold essential information about the tyres we are currently using on our vehicles.
Usually, this would be the original equipment tyres - or the tyres that came with your car when you first bought it.
OEM tyres were designed for your vehicle, so naturally, they would be the best choice. So knowing what the tyre ratings are can help you narrow down your options for a replacement set of tyres.
However, this can also go the opposite way. You might need a new set of tyres that reflect your current driving habits.
You will still need the information found in the tyre ratings of your current tyres to help you choose a new set that is still within the parameters required for your vehicle to ensure your safety.
Need further help?
If you need more help or a more in-depth, one - on - one discussion about tyre ratings and how it can help you choose your new tyres, send us a message, and we will be happy to help you.