What do I need to know about UK tyre law?
What do I need to know about UK tyre law? UK law requires that your vehicle is fitted with the correct type and size of tyre for the vehicle type you are driving and for the purpose it is being used. This means fitting the right tyres and for safety ensuring that they are inflated to the manufacturer's recommended pressure.
The legal limit for minimum depth of the tread on your tyres is 1.6 millimetres, across the central ¾ of the tread around the complete circumference of the tyre.
For safety reasons it is recommended that you replace your tyres before the legal limit is reached. Many vehicle manufacturers recommend replacing at 2 millimetres. To see the impact on braking distance of different tyre tread depths. At 1.6 millimetres in wet weather it takes an extra two car lengths (8 metres) to stop at 50 mph than if your tread was 2.5 millimetres.
A regular check of your tyres can help you to avoid 3 penalty points and £2,500 in fines for having tyres worn beyond the legal minimum limit on your vehicle.
Load Index and Speed Ratings
The majority of tyres carry coded markings on them, which correspond to their load carrying and maximum speed capabilities.
For example: 91V
91= Index of maximum load carrying capacity per tyre, in this case equates to 615kg.
V= Symbol which equates to a speed rating of 240km/h (approximately 149mph)
The load index is a numerical code, which corresponds to the maximum load a tyre can carry at the speed indicated by its speed symbol, under specific service conditions. For specific load index details see below.
Tyre Pressure Correct tyre pressure can help to extend the life of your tyre, improve vehicle safety and maintain fuel efficiency. Pressure is measured by calculating the amount of air that has been pumped into the inner lining of your tyre in pounds force (PSI) or BAR pressure.
The manufacturer of your vehicle specifies the suitable pressure, and it is your responsibility to make sure that the pressure is checked and corrected on a regular basis, at least every couple of weeks.
Maintaining correct Tyre Pressures
There are three main reasons why maintaining the right tyre pressure is important. The first is safety. Tyres that are under inflated can overheat; and over inflated tyres can lead to poor vehicle handling on the road.
The second reason is economy. Over or under inflated tyres suffer more damage than those with the correct pressure and need to be replaced more regularly. Vehicles with under-inflated tyres have increased rolling resistance that require more fuel to maintain the same speed.
EU Tyre Labelling Legislation
Everything you need to know
On 1st November 2012 the new EU Tyre Labelling legislation comes into force. All new car, 4x4, SUV, van and most truck tyres manufactured after 1st July 2012 will carry a new ‘tyre label’ which is similar to the energy stickers that appear on white goods. The new label will provide you with objective, reliable and comparable information about your tyre purchase. Tyres manufactured before 1st July 2012 may still carry an old style label.
Your drive to purchase
The tyre label will focus on three areas of performance and will raise some very important questions when making your tyre purchase.
Fuel Efficiency - How economic is this tyre? - Savings
Wet Grip - How quickly can the tyre stop in wet conditions? - Safety
Exterior Noise - How noisy is the tyre? - Sound
Breakdown of the Label
Fuel Efficiency / Rolling Resistance
A rolling tyre deforms and dissipates energy. The energy that's lost is known as rolling resistance and directly impacts on fuel consumption. The difference in fuel consumption between a car fitted with A and G class tyres is around 0.5 litres per 100km, that's a saving of around 80 litres and more than £110 per year.*
*Savings based on a petrol engine car travelling 10,000 miles/year with £1.40/litre fuel cost.
Tyres with excellent wet grip have shorter braking distances on slippery roads, essential for keeping you safe in the rain.
These ratings are measured from the distance travelled by a car after braking at 50mph in the wet.* 30% shorter braking distance between best and worst class for a full set of tyres fitted to an average car.
*Testing according to regulation EC 1222/2009
Exterior noise levels are measured in decibel(dB) and shown as one, two or three sound waves on the label. One wave is the best performance, three is the worst. In fact, three bars is the current limit, while two meets future laws and one is a further 3dBs below.
Note: External tyre rolling noise is not related to interior vehicle noise.
Essentially - the amount of air inside the tyre. Measured in either pounds per square inch (psi) or bars. The correct pressure for tyres can usually be found in the vehicle handbook and often on the flap to your petrol tank.
Alignment is a process that ensures the suspension and wheels in association with the steering are in accordance with the manufacturers specification for the optimal way the wheels should be pointing.
This is a way of expressing a tyre's height as a percentage of its section width. This figure is always found on the sidewall of the tyre.
Tyre balancing is a process to ensure that the when the tyre and the wheel spin their weight is equally distributed.
A ring of steel wire, within a rubber ‘wrapper’, that helps to hold the tyre to the rim
This is the skeleton of the tyre sitting underneath the tread and sidewalls
Cold Inflation Pressure:
This is the tyre pressure before the tyre has been able to heat up from driving.
Cold weather tyres:
Tyre designed to give better grip below temperatures of 7 degrees. Also known as winter tyres but snow tyres are something different.
The area of the tyre's tread that is in actual contact with the ground. (See Contact Patch)
In a tubeless tyre, the innerliner prevents air from seeping out of the tyre.
Metric unit for air pressure. (1 bar = 14.50326 psi)
This is a code that ranges from 0 to 279 that quantifies the maximum weight a tyre can bear at the spped indicated by the speed symbol under certain service conditions.
Low profile tyres:
a description of tyres that are quite ‘thin’ in comparison to the radius of the wheel
Maximum Inflation Pressure:
The maximum pressure that a tyre can be inflated to.
Pounds per square inch (psi):
The imperial unit for air pressure.
the metal edge of the wheel on which the bead is seated enabling the tyre to be supported.
The diameter of the rim bead seats
Distance between the two opposite inside edges of the rim flanges.
The energy needed to keep a tyre moving at a constant speed. A low rolling resistance means less energy is being used to keep a tyre moving.
Run flat tyres enable vehicles to be driven, at reduced speeds for a limited time until they can be replaced.
Tyre height from rim to the outer tread.
The measurement of the tyre from side to side excluding any additional sidewall items such as raised letters.
Found where the sidewall and tread meet.
The area between the bead and the start of the tread.
Slits in the tread designed to improve grip in wet conditions
Used to identify a specific tyre. It includes width, construction type, aspect ratio and rim size.
Speed rating to indicate the range of speeds at which a tyre can carry a load under a range of conditions. Ratings are categorised from A-Z.
Made of a mixture of rubber, chemicals, fabric and metal their job is to give the car traction on the road in a variety of conditions, and to cushion the car from shock.
information on the recommended pressure, rim size and load capacity can be found in your vehicle handbook and sometimes on the inside sill of the drivers door.
The part of the tyre that comes into contact with the road
Narrow bands in the tread grooves that provide a visual warning to a tyre needs changing, since they can only be seen if the tread has worn below the 1.6mm threshold.
Tread width is the portion of the tyres width that is covered by a tread pattern.
The condition that exists when there is not sufficient air pressure in a tyre.