The tire’s tread pattern design is made up of different elements that all work together to provide the performance intended for the type of a tire.
Tread Block – the large elements in the tread design that do most of the work, providing traction and grip.
Tread Grooves – the larger slots in the tread block that typically run laterally across the tread face, providing wet and snow traction.
Circumferential Grooves – the main channels in the tread face that allow water to drain from the contact patch.
Sipe – the small, thin slits or tiny grooves in the tread block that provide the “biting edge” for enhanced wet and snow traction.
Rib – a group of tread blocks or solid section in a circumferential row going around the tire.
Tread Shoulder – the area at the edge of the tread pattern when it merges into the sidewall. This area comes into contact with the road surface in heavy handling maneuvers.
Void Ratio – this is the amount of open space in the tread. It’s defined as the sum of the groove and sipe area divided by the total tread face area. It can also be referred to as the “sea-land ratio” or “net-to-gross”.
Treadwear Indicator (TWI) – the treadwear indicators are humps molded into the circumferential grooves that indicate the tire is worn out and needs to be replaced if the tread becomes even with that level. They are spaced around the tire in multiple locations and their location is typically marked on the tread shoulder with a “TWI” or triangle symbol.