Snow Traction
Snow traction refers to the braking and acceleration forces a tyre can generate on snow-covered surfaces.
Snow traction performance varies significantly depending on snow depth, compaction, and structure, such as fresh flakes versus hardened crystals.
A tyre’s snow traction performance relies on the abundance and density of biting edges in the tread that can grab the snow.
Additionally, the tread is designed to allow for squirm that will provide more biting edges as the tyre deforms.
Testing for Snow Traction
Snow and ice conditions can change dramatically over the course of a few hours or an entire day.
To ensure consistency as much as possible, snow traction testing should be conducted on a groomed, controlled snow surface.
Testing engineers can also use standardised procedures to correct for bias variations in the testing data.
Snow traction testing is largely conducted on instrumented vehicles that are equipped to measure driving and braking traction.
There are standard protocols for snow traction testing, as well as custom protocols specific to individual tyre or automotive OEMs.
Tread Attributes Benefiting Snow Traction
A tyre engineer seeking to optimise snow traction performance in a tyre may;
- Decrease the contact area and increase void area.
- Maximise all lateral structures to make more biting edges. For example, this often includes increasing the quantity and size of sipes in all five ribs.
- Minimise tie bars to minimise constraint of elements and allow for more deformations that produce biting edges.
- Maximise tread depth.
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