What is a Tire Stud?
A tire stud is a traction device that is installed into the tread of rubber tires. It consists of an outer jacket of steel or aluminum and a tungsten carbide pin that provides the traction. On passenger tire studs, this tungsten pin is 1mm in diameter and protrudes approximately 1mm from the top of the stud.
Do Studs Work?
Extensive testing by the tire and automotive industry as well as various government agencies have proven that tire studs can improve traffic safety in icy winter driving conditions. Tire studs increase tire friction on icy surfaces enabling drivers to stop sooner, accelerate quicker and maintain control on turns.
Are Tire Studs Legal?
Tire studs are legal to use in many states and all provinces except southern Ontario. Most highway departments have regulations that prohibit tire stud use during summer months. Please refer to our Stud Law/ Seasons section or contact your state or provincial highway department.
How Do I Get Studs Installed?
Tire studs are usually installed at a tire service center using specialized equipment. Many brands of winter tires have pre-molded holes designed to accept tire studs. We recommend that only new tires be studded as previously driven tires have stud holes that are plugged with dirt and can not be studded properly.
How many studs are in a tire?
Each passenger tire is designed to accept from 80 – 120 tire studs depending on the tire diameter and hole pattern. Larger diameter truck tires generally require more studs.
What size studs do I need?
In North America, tire studs are sized by a TSMI number. Winter tires have pre-molded holes specifically designed to accomodate a certain size stud. Passenger tires and light truck tires use either TSMI #11, TSMI #12, TSMI #13, TSMI #15, TSMI #16 or TSMI #17 size studs. Many tire manufacturers indicate on the tire sidewall the correct TSMI number stud to use. If it is not indicated, then the service center must measure the stud hole depth and match it to the body length to determine the correct stud for that tire.
How far do studs protrude?
A correctly installed tire stud will have only the 1mm tungsten carbide pin protruding from the tire tread. A maximum of 1mm of the body may also protrude as the stud will seat correctly in this condition. Certain specialty studs and Rally racing studs have much more prominent protrusion. However, these rally type studs should not be driven on bare pavement.
Do studs ruin roads or fly out?
Extensive testing by highway departments throughout the world have concluded that modern winter tires and tire studs do much less damage to roads than the studs used 40 years ago. The use of radial tires, better road compounds and lighter weight studs have all contributed to significantly reduce road wear and rutting.
A properly installed tire stud has little chance of coming out of the tire during driving. The rubber of the tire compresses very strongly around the base flange of the stud and the rotational speed of the tire is not strong enough to dislodge the stud.