Along with "winter tyres", equipped with winter tread pattern and marked as M+S (Mud+Snow), there are also tyres carrying both M+S and 3PMSF ("Three Peak Mountain Snow Flake") markings on their sidewalls. 3PMSF symbol means that the tyre 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" tyres and establish the best solution for safe winter driving on roads covered with frost, ice and snow.
3PMSF tyres showed better performance than M+S tyres on snow-covered flat roads (vehicle installing M+S tyres have spent 10 percent more time than the vehicle equipped with 3PMSF tyres to cover the same distance) and summer tyres (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 tyres, as they provide better traction, handling and safety. "Mixed" configuration (two 3PMSF tyres on the front axle and two summer tyres 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 tyre fit, as well; actually, when fitted with summer tyres, they can quickly become uncontrollable when driving downhill or uphill, while if fitted with winter tyres (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 tyre fitting equipment, able to provide high efficiency and high performance. As you care about your uncompromising safety, choosing premium brand tyres, so tyre service professionals should use high performance tyre changers, able to handle your tyres without risk of damage.
SX 234 (link to video) today is the best among all traditional tyre changers for easy fitting/removing all kinds of tyres. Make sure your trusted tyre service professional has one!