Along with "winter tires", equipped with winter tread pattern and marked as M+S (Mud+Snow), there are also tires carrying both M+S and 3PMSF ("Three Peak Mountain Snow Flake") markings on their sidewalls. 3PMSF symbol means that the tire has been tested for use in difficult snow conditions.
A series of tests (including driving and instrumental testing) conducted by Assogomma and Federpneus on the snowy roads of La Thuile, in the Valle d'Aosta region, allowed to compare 3PMSF, M+S, and "summer" tires and establish the best solution for safe winter driving on roads covered with frost, ice and snow.
3PMSF tires showed better performance than M+S tires on snow-covered flat roads (vehicle installing M+S tires have spent 10 percent more time than the vehicle equipped with 3PMSF tires to cover the same distance) and summer tires (driving time was 30 percent more in this case).
Drive tests performed under winter conditions on Jeep® Renegade, confirmed that the best solution is to fit a set of four 3PMSF tires, as they provide better traction, handling and safety. "Mixed" configuration (two 3PMSF tires on the front axle and two summer tires on the rear axle), although not forbidden by law, proved to be dangerous, as it provided a false sense of safety on straight roads and loss of rear axle grip on turns or during braking, which may cause loss of vehicle control.
4WD vehicles need their own proper tire fit, as well; actually, when fitted with summer tires, they can quickly become uncontrollable when driving downhill or uphill, while if fitted with winter tires (with M+S marking), they may have some issues during more demanding driving situations (eg. start at bottom of a hill...).
As always, safety depends upon the choice of best tire fitting equipment, able to provide high efficiency and high performance. As you care about your uncompromising safety, choosing premium brand tires, so tire service professionals should use high performance tire changers, able to handle your tires without risk of damage.
SX 234 (link to video) today is the best among all traditional tire changers for easy fitting/removing all kinds of tires. Make sure your trusted tire service professional has one!