Tyre Tread Development
The tread is a unique and critical component of the tyre. The tread creates the contact patch between the vehicle and the road, maintain friction and enabling the driver to control the vehicle. It is also the heaviest of the major tyre components, comprising roughly one-third of the tyre’s total weight.
The tread has a long list of performance expectations, from traction and handling to wear resistance. Nearly all of these performance attributes are heavily influenced by the design of the tread.
These sections deliver an overview of how tread design affects different performance attributes.
Tread Nomenclature
In this graphic, the black area represents the actual contact area of the tyre against the driving surface, and the white area represents non-contact or void areas.
A typical five-rib construction tyre
The outer ribs are referred to as shoulder ribs, the middle rib is referred to as a centreline rib, and the other ribs are referred to as intermediate ribs.
These ribs are separated by four circumferential grooves.
The shoulder and intermediate ribs have a variety of lateral slots, which are wide grooves.
All five ribs have sipes, which are fine lateral slots.
Also visible are tie bars, moulded rubber links which tie elements of the tread together to reduce squirm of the footprint area.
When testing tyres, the tread depth can refer to two different measurements taken from the cross section: the depth of the tread all the way to the bottom the groove, or the depth to the tie bar.
Different investigations will use different tread depth measurements depending on context and purpose.
This information has been reproduced with the kind permission of Smithers
Smithers is an independent, third-party testing and consulting company with a history in the tyre industry starting back in 1925. Their team has many years of experience in the tyre and rubber industries and have created this information as an educational resource on the general science behind tread development.
As an organisation, Smithers do not actively develop tyre treads for commercial use in the market.
Tread design is a complex, highly specialised activity that must take into account each manufacturer’s design and development goals.
© SMITHERS, 2021