What Tyre Size Fits My Car? A Guide for Purchase

If your car tyres are worn out and you need new ones, but you wonder “What tyres fit my car?” With so many factors to be considered, the right purchase could save your life.

Choosing the right tyre size is important and all of the information you need can be found directly on your old tyre.

What’s all those numbers on the tyre?

Take a closer look, and you will see a few numbers and letters on your tyre that will help you select the right size. Let’s decode them!

*Using the number series – 195/55 R16 87V

  • 195 – Section width or width of tyre
  • 55 – Aspect ratio or profile
  • R – Construction type of tyre
  • 16 – Rim diameter
  • 87 – Load index or load rating
  • V – Speed rating (maximum value)

Understanding tyre size

Section Width

The measurement of the width of a tyre from its side wall (inner) to the other sidewall (outer) is called the 'section width' or sometimes the 'cross section width'.

Some points to consider:

  • Unit of measurement is millimetres.
  • The measurement excludes any protective ribs or raised letters.
  • The rim’s width influences the tyre’s width. So, appropriate industry assigned rims should always be used.

Aspect ratio

The ratio of tyre’s width with the height of its cross section gives this aspect ratio or tyre’s profile. In above example, 60 denote that tyre’s height is equal to 60% of its width. Hence, lower the aspect ratio, the wider the width.

Note: Tyres with a lower aspect ratio (below 60) are high performing. The reason is low aspect ratio gives better stability for lateral forces. Also, with short and stiff sidewalls, cornering forces are resisted.

Construction Type

As shown in the example above, R refers to Radial. It is a tyre design where cord plies are arranged radially from the centre of the tyre at 90 degrees.

Rim Diameter

The rim is the frame that holds the tyre. Rim diameter is the distance of the rim from bead to bead. Its measuring unit is inches. The typical size range is between 12 inch to 28 inch – mainly 15”, 16” and 17”.

Load Index

Load index or load ratings denotes the maximum load that a tyre can take when properly inflated. The manufacturer can best guide to what capacity will be suitable for your car.

A load index table is available here


Speed rating

This indicates the speed a tyre can safely be driven with the specified maximum load of the tyre. The tyre’s speed rating is in letters.

A complete speed rating table is available here.

If you are unsure about the tyre size, you can also get these specifications in your owner’s manual.

Where to buy?

Read the markings on your current tyre carefully; make sure to double check. 

Buy tyres online with our quick and easy tyre finder. Decide on your brand and put in your tyre specifications – width, profile, rim, speed, postcode, etc.

We have great car tyre deals on many trusted brands, and all prices include fitting at your local Protyre centre. With same day fitting available on many tyres! So what are wyou waiting for?

About the author

Dean Richardson

Dean is a Regional Director for Protyre who is also responsible for the running of our Protech Academy. The ...

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