Abstract: A ski includes a longitudinal ski body having an upper surface and a lower snow-contacting surface. A longitudinal slot extends from the upper surface to the lower surface. A longitudinal keel, having at least a portion selectively extending in the slot, is adapted to connect pivotably to a ski leg of the snowmobile. The ski body is connected to the keel and adapted thereby to connect to the ski leg. At least a portion of the ski body is selectively movable with respect to the keel. The ski body is thereby selectively disposed in any one of a plurality of ski body positions, each of the plurality of ski body positions being defined at least by a position of the slot with respect to the keel. A fastener retains the ski body in any one of the ski body positions. Ski assemblies and snowmobiles having the ski are also disclosed.