Need to replace one or more of your car's tyres? You can find this information on the sidewalls of your current tyres. Alternatively, it will be listed in your vehicle handbook, and/or on a label on your door jam or fuel cap.
Another easy way to find out your tyre size is to enter your registration number into a "Find a tyre" search tool online. Some tools also let you search by brand and model.
But you may wish to know exactly how to read your tyre size code. If so, read on:
Here's an example tyre size: 200/65 R16 95V
- 200: tyre width in mm - so 200mm.
- 65: profile; height as a percentage of full tyre width
- R: type of tyre. Most tyres are 'radial' - R. But occasionally a tyre is B (bias belt) or D (diagonal)
- 16: wheel rim diameter in inches
- 95: load index - how much weight it can bear (see below)
- V: this is the speed rating, or maximum speed (see below). In this case, 118 miles per hour.
The first three digits of a tyre code denote the tyre's width. Wider tyres have better traction - but result in more road noise. “200” in the above example.
This is also known as the "aspect ratio" of your tyre. This figure is arrived at by dividing the tyre's sidewall height by the tyre's width, then multiplying the result by 100. “65” in the example above.
The rim is visible after the tyre is removed. The rim width measurement will be slightly different from the tyre width. These figures are therefore listed separately. “16” in the above example.
This figure - - corresponds to the load capacity of the tyre, i.e. the maximum load the tyre can carry at the speed rating listed. "95" in the above example means 1,521 lbs or 690kgs at the speed rating below.
This denotes how fast the vehicle can go at the specified load index (see above). "V" in the example above, or a maximum speed of 149mph at the “95” load index.
Tyres marked with either XL or RF have been specially made to deal with heavier loads.
These tyres are manufactured with reinforced sidewalls, so in the vent of a flat tyre, the vehicle can be driven up to 50 miles at a top speed of 50mph. Brands with models that offer Runflats include Mini, BMW, Mercedes and Audi.
As the name suggests, these tyres feature sealant inside that closes over a hole caused by a foreign object - such as a nail.
Most car owners only change tyres when their old ones wear out or show signs of damage. Most driver's buy replacements of the same size. However, some people change tyre size to improve certain driving parameters of their vehicle. While this may offer improvements in some regards - such as shorter braking distances - they invariably come with drawbacks - such as a more rigid ride or more road noise. You should not choose a new tyre size for which your vehicle is not suited.