What Tyres Fit My Car

When it comes to tyres, it isn’t a case of “one-size-fits-all”. With such a wide variety of available sizes, it can be difficult to know which set is the right fit for your vehicle.  If you’re also wondering “what tyres fit my car?” - then wonder no more: our comprehensive guide can help you to find the ideal fit for your car, whatever the weather or terrain.

How Do I Find The Right Size Tyres For My Car?

Speed Index and Compatibility

Tyre size compatibility depending on outer dimensions (diameter/rolling width and circumference) and labelled as a standardised tyre size indicator as found on the sidewall.

The size of the tyre must also comply with the vehicle requirements for load range and speed rate. Together, the load and speed index make up the full service description for a passenger car tyre, which must correspond to the information provided in the vehicle documents.

Speed Index

Tyre speed capability must be at least equivalent to the top speed of the vehicle.  Speed rating indicates the maximum permissible speed (at full load of a tyre), and whether it’s appropriate for your car.

Load Index

This is the maximum capacity of a passenger car tyre, calculated by the maximum permissible axle load range between two tyres.

Where To Find Size Details For Your Tyres

There are a few ways to determine the best size tyres for your car:

• Usually, you can find a sticker on the inside of the driver side door jamb (this will also give you information on tyre pressure.
• Alternatively, you can check inside the fuel flap or glovebox.
• Another method is to simply look at the tyres that are currently on the car - however if you recently bought the car second hand, there’s no guarantee that the previous owner will have fitted the car with the correct tyres.
• A third way is to consult the car manual - if this is unavailable in hardcopy, you can usually find one either through the manufacturer or online (even older models).
• You can also find your car tyre size by registration plate - it is recommended that you use the manual to check this against.

Finally, you can also check the vehicle documents - these will give you the recommended tyre size for your car in addition to You can also find the tyre size on the enclosed certificate of conformity (CoC) - this provides information on alternative tyre sizes. If this is lost or misplaced, again you can contact the manufacturer.

How to Read Tyre Size On The Sidewall

Another option is to check the tyres themselves. Tyre markings on the sidewall correspond to specific markings that will tell you the size of tyre you need. Typically, there are twelve markings in total - but for the purposes of sizing you will only need the following six:

1.  Width of the tyres, in millimetres
2. The percentage height of the sidewall relative to the width
3. Radial construction of the tyre
4. Rim diameter (in inches)
5. Load index (maximum load capacity of the tyre)
6. Speed index (the maximum speed of the tyre)

When choosing your tyres, there are two simple rules you need to follow.

Firstly, ensure that the replacement tyres are the same load and size index - and that they have the same speed rating specification as recommended by the tyre or vehicle manufacturer.

Secondly, replacement tyres should never be smaller or have a lower load-bearing capacity than stated on the original specification.

Can I Change The Size Of My Tyres?

Tyre size should be selected according to tyre manufacturer recommendations and vehicle documents. If the combined tyre and wheel diameter are not correctly matched, there may be major differences in speedometer ratings and ride height.

Switching sizes can only be done in accordance with all legal regulations and requirements in addition to the recommendations of the tyre, wheel and vehicle manufacturers. At a minimum, the wheel must have complete freedom ocricultar motion and should not be carrying over the recommended weight.

In some instances, a different size of tire may be used , but the same new tyres (with the same tread pattern, tyre size and tyre age are needed to fit across the axles. To ensure safety, consult your manufacturer before any changes are made. If you drive without approval you risk accidents and fines.

Car tyre sizes are measured and shipped in relation to the size of the rims they’re mounted on. The rims themselves are designed to account for the overall size of the wheel - which in turn affects things like suspension and steering.

If the size of the rims are changed, it is possible to change the size of the tyres - so long as the diameter of the wheel remains the same. To do this, the speedometer would have to be recalibrated with most of the changes to tyre size - and tyre pressure would also have to be adjusted accordingly.

Can I Mix And Match Tyres?

Tyres should never be mismatched on an axle pair. The reason for this is that the tread pattern is designed to divert debris and water away from the tyre so that it can grip the road.

Having different tyres with a variety of tread patterns that divert in other directions can put uneven stress on the entire system, leading to premature and uneven wear on all parts of the system. This in turn can then reduce grip on loose ground or in wet conditions.

The internal construction of tyres on any chemical must be either bias-ply or radial. Mixing the two types is unsafe and illegal, with the only possible exemption being in cases of emergency. Regarding wheels or rims, the same rules apply.

I’ve Found My Size - What Next?

Once you’ve the matching tyre size for your car, the next stage is to determine which type of tyre suits your needs. This can include, but is not limited to winter, wet braking and all-season tyres. For advice and assistance with fit and sizing, contact your local tyres Manchester or tyres Stockport specialist for details, depending on which area you are based in.