All About Tyre Speed Ratings
That your car tyres have codes and markings stamped on their sidewalls. These markings will tell you what you need to know about how suitable the tyres are for your car. The numbers and letters relate to the tyre’s size, dimensions, composition and speed capability, as well as other factors.
Reading tyre specs
Let’s say that your tyre is stamped with 175/65 R14T; what does this all mean?The 175 is the tyre’s width in mm, so your tyre is 175mm, or 17.5cm, in width.
Then there’s the ‘65’ part of the 175/65. This means that the sidewall profile of the tyre is 65% of the width, which in this case is 113.75mm or 11.375cm.
The profile is also sometimes known as the aspect ratio and the bigger the aspect ratio, the taller the sidewall is.
You’ll also see the letter R in your markings and this tells you that the tyre is of radial construction, as are almost all tyres now.
The 14 means that the diameter of the tyre is 14 inches (note the use of inches rather than centimetres).
The T is your speed rating (more on this later).
You might also see XL emblazoned on your tyres. This doesn’t mean that they’re extra large, though. It means that the tyres are reinforced to enable them to withstand a higher load – an eXtra Load – than other tyres of the same size and construction.
Bi-directional or symmetrical tyres
Another thing you might notice is an arrow on your tyre, to tell you which direction it should roll in, and this means your tyre is asymmetrical or unidirectional. There are also symmetrical or bidirectional tyres; you’ll see that the inner and outer edges of these tyres have the same pattern (in mirror image), so the tyres can be fitted to roll in either direction. Bidirectional tyres and their treads don’t offer any specific advantages over asymmetrical treads, but they’re cheaper to produce.
Winter tyres are becoming more popular in the UK
While winter tyres have been a legal requirement in many European countries for years, they’re only just starting to really catch on in the UK.
Winter tyres are designed and manufactured to offer a better grip on colder, wetter and even snowy roads. A set of winter tyres can actually shorten your braking distance by up to eight metres on snow or ice. You’ll be able to spot winter tyres by an embossed snowflake or a snowcapped mountain on the sidewalls.
All about the speed ratings
When it comes to tyre speed ratings, it’s vital that the tyre matches or exceeds the car’s top speed. You’ll find this information in your handbook, or you can consult your local garage, but here’s a general reference guide to the ratings.
S 180km/h or 112mph
T 190km/h or 118mph
U 200km/h or 125mph
H 210km/h or 130mph
V 240km/h or 149mph
W(ZR) 270km/h or 168mph
Y(ZR) 300km/h or 186mph
ZR Above 240km/h or 149mph
You’ll also see the tyre manufacturer’s name, the model name and the location the tyre was made in.
Understanding your tyre energy labels
The tyre energy label has been mandatory on all new tyres made and sold since November 2012. This label aims to tell consumers which tyres are the most economical to buy and use. The label also incentivises manufacturers to make better tyres in the same way that energy labels on domestic appliances has.
Tyre suppliers must provide the ratings and information on all promotional material, including on leaflets and in online information. Retailers must also make sure that this information is visible and available to buyers at the point of sale.
What does the energy label show?
The tyre energy label shows the following three aspects of a tyre’s performance:
Fuel efficiency is a measure of your tyre’s rolling resistance. The rolling resistance is the amount of energy lost as your tyre rolls, due to the constant deformation of the tyre as it rolls. Lower rolling resistance means the tyre needs less energy to roll, therefore giving you better fuel economy.
Your tyres have a grip rating so that you know the manufacturer hasn’t reduced grip in order to secure a good energy rating. Wet grip is based on how quickly you can brake in a straight line in wet conditions.
In the real world, your braking distance depends on several other factors, but tyre industry experts say that using grade A tyres gives you a 30% shorter braking distance over grade G tyres.
Your tyre roar – the noise a tyre makes against the road surface – is an important factor for driving comfort and for its environmental impact.
Exterior noise levels have three categories of noise (which is measured in decibels). You’ll see between one and three curved bars on the tyre icon, which shows how the tyre’s noise compares with EU regulations.
The quieter the tyre, the better, as it reduces in-car fatigue on long journeys and also results in less overall noise pollution.
One sound wave – more than 3dB quieter than the EU limit (which is very quiet).
Two black sound waves – already compliant with the EU’s planned limit (fairly quiet).
Three black sound waves – above the current EU limit (which is the noisiest allowable).