Traction systems for snowmobile skis producing traction on snow and ice covered surfaces; consisting a pair of snowmobile skis each having an assembly of parts; driven by an hydraulic rotor that pivots the skis, adjusting their position when cornering, providing traction, according to a snowmobile steering system . And is powered and controlled by at least one of: hydraulic steering system, an electro-hydraulic steering system; an electric power steering system using an electric motor instead of hydraulic rotor.

Traction systems for skis producing traction on snow and ice covered surfaces; the skis selected from a group consisting a pair of Back Country skis each are mounted with an apparatus; having DC powered controls, tilt switch, pressurized carbon dioxide (CO.sub.2) gas powered pneumatic actuators operating gripping parts; controlled by a servo unit. And further consisting a pair of snowmobile skis each having an assembly of parts; driven by an hydraulic rotor that pivots the skis, adjusting their position when cornering, providing traction, according to a snowmobile steering system. And is powered and controlled by at least one of: hydraulic steering system, an electro-hydraulic steering system; an electric power steering system using an electric motor instead of hydraulic rotor.

A rear portion of a ski mountaineering binding has a base with a turret rotatable into a first position. The binding portion attaches to a ski boot heel for downhill skiing. The turret has a second position for walking uphill. A ski brake includes a braking lever rotatable to assume a braking position and a non-active position. The brake has elastic for rotating the braking lever towards the braking position, the braking lever is pressed by the ski boot heel, when the turret is in the first position, in order to reach the non-active position. A rotation member rotatably borne by the base bears the braking lever. The rotation member and the turret are interconnected and solidly constrained to one another, with the turret in the second turret position and the braking lever in the non-active position, to enable walking uphill.

A heel piece for a ski binding. The heel piece includes: base plate which is adapted to be fastened, for example screwed, to an upper side of a ski; a base body which is fastened to the base plate and pivotably mounts a heel retainer; and a ski brake including two brake arms. The base plate pivotably mounts the brake arms and forms a contact surface for the sole of a ski boot.