Read Tyre MarkingsMany drivers, while familiar with the size of engines and familiar with the need or regular services and oil change, are completely unaware of the importance of the patch of rubber that is between the car and the road, the tires.

Car tires come in various sizes and profile, to know what they are is to learn how to read the side markings. Together with the brand and product name, there is always a standard row of numbers and letters describing the size and profile of the tire, like in this picture: 205/65R15

  • 205 denotes width in of tire in millimeter, in this case, 205mm.
  • 65 denotes the aspect ratio, which is the height of the side wall of the tire. 65 basically means it is 65% of the width of tire, in this case, the wall of the tire is 133.25mm tall.
  • R means the tire is of Radial construction, true to pretty much all modern road cars. The other type is cross-ply construction, mostly only found in vintage cars.
  • 15 is the size of the wheel rim the tire fits, in inches.

Read Tyre MarkingsNotes:
Performance cars usually have a smaller aspect ratio as well as wider tires for better handling around the corners. To allow this and yet keep the overall circumference, bigger rims are needed.

On tire pressure:
Most sedan car tires work well at around 29-31 psi, or around 200 to 210 pascal. For optimal performance and fuel economy (low pressure = increase fuel consumption, high pressure = less grip), check your vehicle manual for optimal tire pressure. The information can also usually found at the body of the car where the driver door closes, or at the inside of the driver door itself.

How to Read Tire Marking
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One thought on “How to Read Tire Marking

  • February 11, 2009 at 10:01 pm

    i cam across 77 tires in what look like good shape however they are marked the old way hr 78 15 is just 1 of the examples there seems to be 12 13 14 15 16.5 and at least 1-
    22.5 can you tell me the old sys or is it better to just pay 3.50 a tire to disposse of them. eny help with this matter is greatly helpfull thank you for takeing the time to read this c.g.


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