Studded tires reduce accident rates on snow- or ice-covered roads, according to a 2002 research report published by the Washington State Department of Transportation, but exchanging them twice yearly with conventional tires is a chore. Motorists choosing tires with retractable studs can save time and money by using the same tires all year round.
In good weather, retractable studs stay below the surface of the tire and do not contact the road. When a driver encounters snow or ice, he flips a switch on the dashboard, which extends the studs by inflating a secondary air chamber inside the tire.
When used on roads that are free of ice and snow, studded tires damage the road surface. Hazardous driving conditions result, and repair costs sustained by the state can be substantial. Using retractable studs can prevent this damage.
Many states prohibit the use of tires with fixed studs outside winter months. As of 2011, several states, including Maine, Oregon, Washington, Idaho, Nevada and Montana permit drivers to use retractable studded tires throughout the year.
Air pressure is lost when inflating and deflating the secondary chamber within the tire. Q Tires, a manufacturer of retractable studded tires, claims that studs may be deployed and retracted 20 to 30 times before a driver needs to top up his tire pressure.
