Tyre Terminology Explained

If you come across a tyre term that you don’t know the meaning of, be sure to refer to this handy glossary of tyre-related words from Beaurepaires.

  • Aspect Ratio - Also known as the profile, the aspect ratio is the ratio of the height of the tyre's cross-section to its width. For example, if a tyre has an aspect ratio of 65, this means the tyre’s height is equal to 65% of its width.
  • Bead - This is the part of the tyre that contacts the rim on the wheel. It fits close to the two rims on the wheel to ensure that a tubeless tire holds air.
  • Kevlar - Kevlar is the registered trademark for a synthetic fibre developed in 1965.
  • Load Index - The load index is a number that corresponds to the maximum load in kilograms that a tyre can support when properly inflated. You can also find the maximum load supplied in pounds and kilograms moulded elsewhere on the tyre sidewall.
  • Pneumatic Tyres - Pneumatic tyres are comprised of a flexible material, such as rubber, with reinforcing materials such as wire.
  • Sidewall - This is the bridge between the tread and bead of a tyre.
  • Silica - This chemical compound, which is also known as silicon dioxide, is added to the rubber in tyres.
  • Tread - The tread is the raised rubber on the surface of the tyre which makes contact with the road.
  • Tyre Type - Tyre types define the proper use of the tyre. For example, “P” indicates a Passenger car tyre and “LT” means the tyre is for a Light Truck.
  • Tyre Width - This is the width of the tyre measured in millimetres from sidewall to sidewall.
  • Wheel Diameter - This is the width of the wheel from one end to the other.