Car Tyre Buying Guide

Tyres - Car-Tech

Understanding the numbers on your tyres


The first thing to look out for when it comes to car tyres are the numbers stamped on the side of each tyre. These numbers show vital information about the tyres, but it isn’t always clear what they mean.

Tyre Sidewall - CarTech

For instance, you may see something like this printed on the tyre: 185/65 R 15 88 H (XL). The first number, in this case 185, is the tyre’s diameter in millimetres.

The second number ‘65’ is the tyre’s height, as a percentage of the width. If the second number is 50 or less, then the tyre can be considered ‘low profile’. Low profile tyres offer a firmer ride with better handling, but you may end up paying a premium for this type of tyre.

The next number has an R in front of it, which refers to the rim diameter. In this example, this tyre’s rim is 15 inches in diameter.

The last two sets of letters refer to the maximum load and maximum speed that the tyre is rated for. So on the above tyre it would be H which is 130MPH.

For more speed ratings please see below:

Tyre Speed Ratings - CarTech

XL is short for Extra Load or reinforced, you would normally find this on an SUV or heavy goods vehicle. Please read below about reinforced tyres

What does Reinforced mean on tyres?

Sometimes your tyres may have the word ‘Reinforced’ printed on the sidewall; or perhaps it is a two to five long combination of letters. In the table below, we explain what these letters mean.

If your tyres have an increased load rating, they have an indication on the sidewall to show that they have been reinforced to handle the weight. It can often vary depending on your manufacturer.

'Reinforced' Combination Definition
XL Extra Load
EXL Extra Load
RF Reinforced
REINF Reinforced
RFD Reinforced
Are my tyres Run Flat Tyres?

If your tyres are Run Flat Tyres, you will see a small combination of letters displayed after the date of manufacture.

Run Flats are specially manufactured tyres that boast strengthened sidewalls. This helps to avoid losing pressure in the case of a puncture, ultimately holding the weight of the vehicle until it is possible to be replaced.

Below is a table that represents the different kinds of Run Flat Tyre combinations you may see on your tyres:

Letter Combination Definition Manufacturer
RFT Run Flat Technology Pirelli, Firestone, Bridgestone
EMT Extended Mobility Technology Goodyear
ROF RunOnFlat Goodyear
DSST Dunlop Self Supporting Technology Dunlop
SSR Self-Supporting Run Flat Continental
MOE Michelin Run Flat Michelin
ZP Zero Pressure Michelin
What is Homologation?

Depending on the tyres that you buy, you may see another combination of letters after the Run Flat digits. These letters are the homologation of the tyre; this means the tyres were designed to be specifically used for certain vehicle manufacturers.

Most well-known and prestigious brands have their own designated symbol to show that they have met the tyre manufacturer’s safety standards and have been given an OE status.

Refer to the table below for more information regarding manufacturer’s homologation symbols:

Homologation Symbol Manufacturer
A0 Audi
R0 Audi Quattro and S variants
A Toyota Auris
G Volkswagen Golf
VO Volkswagen Touareg
LRO Land Rover
FO Ford
MO Mercedes
MO1 Mercedes AMG
J Jaguar
N0, N1, N2, N3, N4, N5, N6 Porsche
AR, AZ Alfa Romeo
MOE Mercedes Run Flat
BMW and Mini

Choosing the correct tyres

The key thing when it comes to choosing a tyre is having the right ratings and the right size. If the tyre is too small or too big, it won’t fit onto your wheel correctly. If the ratings don’t match your other tyres or are insufficient for your car (i.e., your car is too heavy for the load rating), then you could end up negating your insurance cover.

If you get your tyres fitted at Car Tech, we’ll ensure the tyre(s) offered are fully compatible with your vehicle. When it comes to tyre quality, you generally get what you pay for. Premium tyres will not only last longer but may also perform better in adverse conditions. Budget tyres may even last up to half as long as a premium tyre, so it may be worth weighing up whether it’s worth paying the extra money for a tyre that lasts twice as long.

All tyre bookings also come fully fitted, which means the prices of our tyres includes the fitting cost, valves* as well as balancing and disposal of your old tyres.

*Specialist valves will incur an additional charge

Remember that if you have a van, campervan, 4×4 or other specialist vehicle, then you’ll need specialist tyres to match – check the ones already in place or just pop down to Car Tech and our team will discuss which tyres can be used.

Seasonal car tyres

Did you know that 95% of road users only stick to summer tyres all year round, despite there being potentially better options for when the weather takes a turn?

At Car Tech, we also stock winter tyres, designed for driving in icy or snowy conditions, as well as on wet roads, alongside all-season tyres that offer many of the benefits from both winter and summer tyres. The benefits to changing tyres in winter or going for all-season are mainly about handling in poor conditions or when the temperature drops below 7ºC, so they’re a good option if you want some extra grip in tough conditions.

Many winter tyres are designed specifically for performing in the snow, with finer treads that allow snow to compact, improving overall grip.

Serving customers throughout:

Leighton Buzzard, Woburn, Houghton Regis and all the connecting towns and villages

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