Sipes are tiny cuts in your tire tread that are positioned to improve traction in snowy, wet and slippery conditions. Take a close look and you will find thousands of sipes on your winter tires to enhance traction. Studies show that properly placed sipes on tires significantly improves stopping distance and traction, even on ice.
Tire Traction and Sipes Go Hand in Hand on Any Surface
In normal conditions, all those tiny cuts help make your tire tread just a little more flexible. Sipes increase the ability of your tires to push into small variations on road surfaces for more complete road contact and a stronger grip. The added ability to conform to the road surface also makes for a smoother ride.
In wet conditions, your tires must evacuate road water to avoid hydroplaning. Most of that water is moved aside through the deep grooves in the tread pattern, but at high speed the surface water can build up in front of the tire and increase the chance of hydroplaning. Your tire sipes help by disrupting the water surface and channelling some of the road water to the sides of the tire.
In winter conditions, sipes increase traction when the end points of those tiny cuts open a bit as the tread is pushed against the road. All those tiny open points effectively bite into the snow and grab some additional traction.
Sipe Technology and Tire Science
Sipes were not introduced on tires until the 1950’s, and then with only simple cuts. Over the decades that have followed, sipe design evolved first from simple cuts into zigzagging patterns for snowy roads. Next came a criss-cross pattern that was designed to keep a stiffer grip when cornering and also offered a lot more edges for increased traction and clawing on slippery roads.
Today, tread design and tire design are constructed and first tested on computer screens. Sipes and other non-circumferential grooves with open ends have historically tended to increase road noise. New designs take sound harmonics into effect, and sipes can now be cut to varying lengths and placed strategically to control additional road noise.
One of the newest innovations is “3D sipe technology”. When these 3D sipes are pressed against the road surface, two of the cut edges momentarily lock together. That stiffens the tread block so it can better hold its form for enhanced stability.
In 2011 Goodyear introduced a new sipe design, which gradually morphs the shape of the sipe cuts to widen them and increase traction as the tread wears away. These sipes start with what appear to be thin cuts in the tire tread, but those cuts are actually the top end of small acorn shaped spaces hiding just below the surface of the tread. When the tire is new, with its fresh tread with deep patterns, the thin slits increase road contact in their traditional way. However, as the tread wears away, and the tire pattern overall becomes more shallow, the previously hidden wider cut-outs are exposed to further increase traction.