Abstract: A suspension well covering device for use with a snowmobile, the snowmobile including a cowling defining a belly pan and a suspension well, the suspension well defining an opening through which a suspension system extends outwardly. The suspension well covering device includes a skirt adapted to be attached to the cowling to substantially cover the opening in the suspension well.

Abstract: A steering ski for a snowmobile is disclosed. The steering ski comprises a ski body and a wear bar connected to a ski bracket. The ski bracket is used to attach the ski to the balance of the snowmobile. The ski body also receives a reinforcing member that reinforces a portion of the ski body which is curved upwardly. Reinforcing ribs travel along the length of the ski body on an upper portion of the ski body. The sole of the ski body or lower surface includes a keel that expand in width from a forward-most portion and then decreases in width rearward of a juncture between a snow contacting portion of the ski body and the upwardly-extending portion of the ski body. A wear bar is positioned along the keel and depends below a lowermost portion of the keel rearward of the widest portion of the keel. The wear bar extends into the ski body through a forward aperture and a rearward aperture.

Abstract: A snowmobile comprises a seat having a soft cushion layer, a more firm boundary layer, and a rigid support structure. Passages are provided between the soft cushion layer and a chamber such that air can be exchanged from within the seat and the chamber depending upon whether the operator is seated on the seat or standing above the seat. When an operator sits on the seat, air is forced out of the seat cushion material and into the chamber. When the operator stands and the seat cushion rebounds, air is provided to the seat from the chamber. The snowmobile also includes a lit trunk. The trunk is lit by a light bulb used for a rear tail light assembly. The light bulb is secured in a mounting plate that is formed of a translucent material that provides a window into the trunk. The light bulb can have an integrally formed socket, which can be translucent as well, to increase the amount of light transmitted into the trunk. The trunk preferably is not the chamber that communicates with the seat.

Abstract: A steering ski for a snowmobile is disclosed. The steering ski comprises a ski body and a wear bar connected to a ski bracket. The ski bracket is used to attach the ski to the balance of the snowmobile. The ski body also receives a reinforcing member that reinforces a portion of the ski body which is curved upwardly. Reinforcing ribs travel along the length of the ski body on an upper portion of the ski body. The sole of the ski body or lower surface includes a keel that expand in width from a forward-most portion and then decreases in width rearward of a juncture between a snow contacting portion of the ski body and the upwardly-extending portion of the ski body. A wear bar is positioned along the keel and depends below a lowermost portion of the keel rearward of the widest portion of the keel. The wear bar extends into the ski body through a forward aperture and a rearward aperture.

Abstract: The present invention provides a snowmobile suspension that provides a substantially constant motion-ration (i.e. reduced falling rate) over the entire suspension stroke of the suspension system. The suspension system includes a suspension assembly that includes a lower arm assembly, a suspension arm, and a shock absorber. The lower arm assembly pivotally interconnects the lower portion of the suspension arm and the lower end of the shock absorber to the slide frame at a location relative to the chassis and within the endless track. The upper portion of the suspension arm and the upper end of the shock absorber pivot independently from each other, and the upper portion of the suspension arm is positioned lower and forward of the upper end of the shock absorber. The upper end of the shock absorber is positioned relative to the chassis and within the endless track.

Abstract: A snowmobile design, including a modular front suspension system and a stabilizer assembly, a lightweight frame structure and a drive train that reduces the center of gravity of the snowmobile. The modular front suspension system for a snowmobile that is substantially self-contained and self-supporting. The present modular front suspension system is assembled around a primary support structure, such as an extrusion or other structural member. The primary support structure can be easily attached to, or detached from, the snowmobile frame. The modularity of the present suspension system decreases assembly costs. A stabilizer assembly extends through the center opening and is mechanically coupled to the ski spindle housings. The chassis for a snowmobile includes a plurality of front structural members defining a motor compartment.

Abstract: An engine mount for a vehicle, such as a snowmobile, that can be used when space for the engine within a chassis is limited and which is easily accessed from the side of the chassis for assembly and repair. The engine mount can be attached to the bottom of an engine that is positioned within a chassis. The engine mount can include four hollow, cylindrical portions. Each cylindrical portion having an axis extending transverse to the longitudinal direction of the snowmobile chassis and receiving a damping mount. Fasteners can be inserted through the chassis to couple with the damping mounts and cylindrical portions in a direction that is transverse to the longitudinal direction of the chassis. The configuration of the damping mounts permits effective damping especially in a direction transverse to the direction of forward travel of the vehicle.

Abstract: A snowmobile four-cycle engine arrangement, includes: a four-cycle engine arranged in an engine compartment formed in the front body of a snowmobile with its crankshaft laid substantially parallel to the body width and having a cylinder case inclined forwards with respect to the vehicle's direction of travel. The engine employs a dry sump oil supplying system and an oil tank separate from the engine is provided. Another snowmobile four-cycle engine arrangement includes: a four-cycle engine having a cylinder head at its top, arranged in the engine compartment and inclined forwards with respect to the vehicle's direction of travel with an intake path provided on the upper portion of the engine body. An intercooler for cooling the intake air is arranged in a tunnel created inside the body frame for accommodating a track belt.

Abstract: A snowmobile includes a chassis having a generally reduced length and a snow flap pivotally attached to the rear portion of the chassis, above the track system. The track system extends rearwardly beyond the chassis, and the snow flap shields the track system above and behind from spraying snow. The snow flap is linked to the track system so that as the track system moves through a range of travel relative to the chassis, the snow flap pivots relative to the chassis with the track system. This configuration prevents damaging contact between the tread and the undersurface of the snow flap and/or the chassis. The reduced length of the chassis decreases the weight of the snowmobile and the polar moment of inertia, thereby improving turning performance. A bumper extends from the snow flap and can be used to lift the rear of the snowmobile more easily.

Abstract: A fuel tank for a motored vehicle featuring a main body portion and an oblong neck portion coupled to the main body portion. The oblong neck portion extends diagonally upward away from the main body portion. The main body portion is configured and positioned to provide a wave interference portion therein.

Abstract: A suspension for a vehicle includes an upper A-arm and a lower A-arm. A leg with an axis is rotatably connected to both the upper A-arm and the lower A-arm. A mechanical link is rotatably connected to the leg so that movement of the mechanical link applies rotational force to the leg to cause the leg to rotate about the axis.

Abstract: A front snowmobile suspension of the type having a ski carried at the front end of a trailing arm. The front end of the trailing arm is pivotably secured to the chassis by a pair of generally transversely mounted radius rods. The rear end of the trailing arm is pivotably secured to the chassis at a position sufficiently closer to the chassis centerline than the front end of the trailing arm that the trailing arm is oriented at an angle of at least about 8°, and preferably at least about 10°, with respect to the chassis centerline. In this location the rear end of the trailing arm may be positioned inboard of at least a portion of a body panel (typically the side panel)—i.e. the rear end of the trailing arm is disposed between the body panel and the centerline of the chassis.

Abstract: A flexible ski which is molded in one piece entirely of Ultra High Molecular Weight Polyethylene plastic. The adjustable flex ski is made up of a ski body which forms the majority of the invention and provides the base from which the other components are formed. This ski body is molded in a flat configuration. The front portion of this ski is given a pre-load function by bending the forward most portion of the ski body in an upward fashion. It is then held in this position by the use of pre-load bar which extends pivotally rearward from the tip of the ski to a ski saddle located on the upper center surface of the ski body. This saddle provides various attachment points for the pre-load bar and can thus, vary the amount of pre-load on ski. The saddle is also supplied with an attachment point for mounting the ski on the vehicle.

Abstract: A front snowmobile suspension of the type having a ski carried at the front end of a trailing arm. The rear end of the trailing arm is pivotably secured to the chassis and the front end of the trailing arm is pivotably secured to the chassis by a pair of generally transversely mounted radius rods which in turn are pivotably secured to the chassis. Each radius rod has an inner end pivotably attached to the chassis and an outer end pivotably attached to the front end of the trailing arm. The outer ends of the radius rods are positioned forwardly of the inner ends of the radius rods a sufficient distance that the radius rods, viewed from the top, form an angle of at least about 15° with respect to a transverse plane that is perpendicular to the chassis centerline.

Abstract: A snowmobile having an adjustable width front suspension. The snowmobile has a chassis and front skis spaced laterally from each other. For at least one of the skis, a mounting column extends generally upward and parallel radius rods, which may be of adjustable length, are pivotally connected between the chassis and the mounting column. The lateral spacing of the front skis may be adjusted by adjusting the length of the radius rods or by adjusting the lateral position on which the radius rods mount to the chassis or the mounting column.

Abstract: A steering ski for a snowmobile comprises a ski body and a reinforcing member. The steering ski has a flat portion for contacting the surface of the ground and an upturned leading portion. The reinforcing member is connected to the upturned leading portion at multiple connection points. The ski and the reinforcing member are coupled to transmit forces in a way that reduces the pressure in the upturned leading portion. The forces are applied to the ski when the snowmobile strikes obstructions in its path and when it lands after becoming airborne. A stopper is provided to transmit the forces.

Abstract: Disclosed is a snowmobile including reduction drive including a planetary gear system having a shaft with a sun gear, a plurality of planetary gears spaced around the sun gear and engaging a ring gear. A second shaft is driven by said planetary gears or ring gear.

Abstract: To enable a rider to control in real time the type of ride he desires, a snowmobile is equipped with a suspension system that includes at least one fluid actuated device which can be adjusted in real time to control the relative distance between the body of the snowmobile onto which the rider sits and the frame, or the slide tracks about which the drive belt is mounted. By setting a constant predetermined desirable distance between the body and the slide tracks, or the frame, of the snowmobile, an optimal cushioned ride for the rider is obtained. The control of the fluid actuated device(s) may be effected at any time manually by the rider, or be effected by a feedback system. The snowmobile is also equipped with an ABS system for enhancing the traction of the drive belt on snow and therefore the control of the snowmobile by the rider.

Abstract: A snowmobile comprises a seat having a soft cushion layer, a more firm boundary layer, and a rigid support structure. Passages are provided between the soft cushion layer and a chamber such that air can be exchanged from within the seat and the chamber depending upon whether the operator is seated on the seat or standing above the seat. When an operator sits on the seat, air is forced out of the seat cushion material and into the chamber. When the operator stands and the seat cushion rebounds, air is provided to the seat from the chamber. The snowmobile also includes a lit trunk. The trunk is lit by a light bulb used for a rear tail light assembly. The light bulb is secured in a mounting plate that is formed of a translucent material that provides a window into the trunk. The light bulb can have an integrally formed socket, which can be translucent as well, to increase the amount of light transmitted into the trunk. The trunk preferably is not the chamber that communicates with the seat.

Abstract: The present invention provides a snowmobile suspension system comprising a slide frame for engagement with an endless track, a suspension arm, a bracket arm, and a rocker arm. The suspension arm has an upper portion adapted to be pivotally mounted relative to a chassis on a snowmobile and a lower portion adapted to be pivotally mounted relative to the slide frame. The bracket arm has an end fixedly connected to the lower portion of the suspension arm. The rocker arm has an upper end pivotally connected to the other end of the bracket arm and a lower end supporting a lower end of a shock absorber, the lower end of said shock absorber being pivotally attached thereto. The upper end of the shock absorber is pivotally interconnected to the chassis. The rocker arm is constructed and arranged such that a lower end thereof is disposed beneath the lower portion of the suspension arm.

Abstract: The recreational vehicle disclosed here is a ski bike with four skis which is steerable using a handle bar. Both the front and rear skis have suspension systems which have shock absorbers. Brakes on each from ski serve to slow the bike and to assist in steering the bike, and a rear brake is used to slow and stop the bike.

Abstract: A steering and suspension system for snowmobiles including a steering linkage connecting a steering handle with a steering spindle on each ski for causing an outside ski during a turn to move outwardly from the snowmobile and the inside ski to move inwardly toward the snowmobile and further including a pair of shock absorbers each connected between the steering linkage and a ski.

Abstract: An improved suspension mechanism for snowmobiles. In particular, an additional set of skis which provide support and stability to a snowmobile when the snowmobile is in deep powder is described. The skis also provide an effective structure for preventing the build-up of snow and ice in the snowmobile's suspension wells. Additionally, a suspension well skirt which provides a barrier from snow for a snowmobile's suspension well is described. The additional skis, in conjunction with the skirt, allow a snowmobile to be propelled quickly through deep snow as well as provide increased steerability to the snowmobile when it is in deep snow.

Abstract: A front snowmobile suspension of the type having a ski carried at the front end of a trailing arm. The rear end of the trailing arm is pivotably secured to the chassis and the front end of the trailing arm is pivotably secured to the chassis by a pair of generally transversely mounted radius rods which in turn are pivotably secured to the chassis. Each radius rod has an inner end pivotably attached to the chassis and an outer end pivotably attached to the front end of the trailing arm. The outer ends of the radius rods are positioned forwardly of the inner ends of the radius rods a sufficient distance that the radius rods, viewed from the top, form an angle of at least about 15.degree. with respect to a transverse plane that is perpendicular to the chassis centerline.

Abstract: An adjustable flex ski for snowmobiles and similar vehicles. This is molded in one piece entirely of ultra high molecular weight plastic or similar materials. The adjustable flex ski is made up of a ski body, which forms the majority of the invention and provides the base to which the other components are attached. The front portion of this ski is given a pre-load function by bending the forward most portion of the ski body in an upward fashion. It is then held in this position by the use of the gas pre-load shock or dampener, which extends pivotally rearward from the tip of the ski to a ski saddle located on the upper center surface of the ski body. This saddle provides various attachment points for the gas pre-load shock and thus, can vary the amount of pre-load on the ski. The adjustability of the ski body can also be enhanced by the use of internally adjustable gas shocks commonly found on the market today. These shocks may be adjustable on the body of the shock or by a remote mechanism.

Abstract: An improved suspension mechanism for a snowmobile comprising a set of primary skis and a set of auxiliary skis whereby the first auxiliary ski is secured to a strut and linkage bracket assembly that operatively connects the snowmobile chassis to the snowmobile's first primary ski, and the second auxiliary ski is secured to a strut and linkage bracket assembly that operatively connects the snowmobile chassis to the snowmobile's second primary ski. The auxiliary skis provide an improved suspension mechanism to support and stabilize the snowmobile when the snowmobile is in deeper snow conditions.

Abstract: A front snowmobile suspension of the type having left and right skis being secured to the chassis by left and right trailing arm ski suspension systems. The front end of the trailing arm includes a generally cylindrical sleeve for pivotably receiving the ski spindle. The top end of the cylindrical sleeve is located rearwardly of the bottom end, giving the sleeve and the ski spindle a rearwardly angled caster. The rear end of the trailing arm is pivotably secured to an adjustable link which in turn is secured to the chassis. The adjustable link is movable to change the caster of the cylindrical sleeve and the ski spindle.

Abstract: A frame structure for a snowmobile includes a frame front end member, right and left main frames, and a connecting mechanism. The frame front end member includes a pair of right and left head members, each being formed into a hollow columnar shape, disposed substantially in the vertical direction, and a cross-member connecting the head members to each other. The right and left head members are connected to front end portions of the right and left main frames. The connecting mechanism is tightly secured to the cross-member. An upper end portion of a suspending member for operably suspending a steering member is disposed at a front portion of a snowmobile.

Abstract: A damping control system for a stabilizer bar with an electronic shock absorber between a low arm and the stabilizer bar for controlling the rolling of the vehicle. Included are a potentiometer, a vehicle speed sensor, a steering angle sensor, an electronic control unit and a voltage amplifier.

Abstract: A chain drive which has an automatic chain tension adjustor. The chain adjustor has a housing cover with a cover head suitable for being turned with a ratchet for transferring torque to an adjacent motor spring. The motor spring is connected to a shaft within a chain adjustor screw housing. A chain adjustor screw within the shaft is urged by the motor spring through the shaft and housing against the chain adjustor arm. The arm pushes the chain and reduces slack in the chain.

Abstract: A propeller driven vehicle for traversing snow and ice covered terrain with improved steering response and stability. The vehicle has a motor driven propeller providing motive force to sustain forward motion of the vehicle regardless of terrain conditions. The vehicle rides on four skis which greatly enhance the stability of the vehicle and prevent the likelihood of tipping during sudden and severe turning. A parallelogram suspension system provides maximum contact between the skis and the terrain while allowing the skis to respond to vertical undulations in the terrain. A foot operated drag brake is mounted in the rear of the vehicle to decelerate the vehicle.

Abstract: A pair of elongated hitch bar assemblies including first and second ends have their first ends universally mounted from the forward ends of front-to-rear extending toe braces of the forward skis of a snowmobile and the second ends thereof releasably anchored to the rear ends of the toe braces.

Abstract: An apparatus for use with a vehicle dynamic characteristic control system employing a steering handle position sensor and a steering handle neutral position sensor to control the dynamic characteristics of an automotive vehicle. The steering handle position sensor is sensitive to steering handle position for producing a steering handle position signal indicative of a sensed steering handle position. The steering handle neutral position sensor is sensitive to steering handle position for producing a steering handle neutral position signal having a first level when the sensed steering handle position is in a predetermined neutral range and a second level when the sensed steering handle position is out of the predetermined neutral range. A first signal is produced when the steering handle position signal indicates the sensed steering handle position being out of a predetermined range including the neutral range. A second signal is produced when the steering wheel neutral position signal is at the first level.

Abstract: A device for steering the rear wheels of a vehicle has a first motor controlled at least with respect to the steering angle of the steering wheel, a gear change mechanism for changing gear ratios, a second motor for controlling the gear ratio by driving the gear change mechanism, a steering mechanism for steering the rear wheels by transmitting a portion of the force equal to the product of the amount that the first motor is driven and the amount that the second motor is driven, a motor failure determination device for detecting motor failure when the amount that either of the first or second motors is driven is zero and the other of the motors is operated, and a control device for controlling both motors so that when motor failure is detected in one of the motors, the amount that the other motor is driven is brought to zero.

Abstract: A snowmobile has an upper hood having a plurality of air intakes, an engine provided downstream of the air intakes, and an air box having an air cleaner and communicating with an inlet port of the engine. An electronic control unit is disposed in a case which is secured to an upper wall of the air box. A deflector is disposed between the air intakes and the case so as to deflect intake air from the case.

Abstract: A traction enhancement system (10) for a snowmobile (12) that includes a front plate member (14) and deflection plates (16) mounted ahead of the snowmobile body (18) for deflecting and compressing fresh, ungroomed snow to enhance traction, startability, and stability of the snowmobile in heavy and rough snow conditions. The front plate member (14) comprises an upper screen (40) offset ahead of a lower screen (42), with both screens being attached to the bumper (36) to angle downward toward the tail section (28) of the snowmobile (12). Each deflection plate (16) is bent along a longitudinal axis and mounted to the tip (32) of the skies (30) to deflect snow to either side of the skies (30). The front plate member (14) and the deflection plates (16) are slidably engaged within their respective receiving tubes (61) and (98), which are attached to the snowmobile (12) to facilitate quick and easy attachment and detachment.

Abstract: A steering post for a snowmobile is positionable in more than one position and includes a bearing which has a two part bearing block and a two part bearing. The bearing includes a generally spherical body with axially aligned oppositely extending cylindrical extensions and a bore substantially the same diameter as the steering post axially aligned with and extending through the spherical body and extensions. The bearing body includes openings axially aligned and communicating with a cavity adapted to receive the spherical body therein. The openings include an encircling chamfered area engagable by the extensions on the spherical body such that when the steering post is out of alignment that it does not engage the bearing body and bind.

Abstract: This is a device for locating the ski tips of a snowmobile by reflecting the beam of light from the headlight of the snowmobile back to the operator by a reflection material applied to the ski locator device and adjusting the locator to provide maximum reflection back to the operator.

Abstract: A suspension/traction unit for a snowmobile is disclosed as having an area of primary support and a two stage angle of attack. The traction unit includes a drive sprocket rotatably mounted to the snowmobile chassis a predetermined height above ground level when the snowmobile is at rest. An endless belt is guided by slide rails such that a low primary angle of attack of about 6 degrees is presented as well as a secondary angle of attack steeper than the primary angle attack making it possible for the snowmobile to effectively start and move in deep snow.

Abstract: A mechanism for adjusting vehicle handlebars includes a lower hub intergral with a vehicle steering column, and an upper hub formed as an integral part of the handlebars. Two opposed diamond-shaped plates rotationally receive both hubs. Two locking gears, one integral with each hub, form various interlocking engagement with one of the plates, corresponding to different handlebar position settings. A release lever, pivotally attached to one of the plates, is pivotable to urge the plates away from one another to release the locking engagment of the gears and projection groove, enabling movement of the handlebars to different settings. A spring loaded detent prevents inadvertent release of the mechanism, and must be moved against the force of a torsion spring prior to the pivoting of the release lever.

Abstract: A vehicle especially adapted for traveling on snow, which has a single endless track made bendable laterally in order to change direction of travel. The vehicle has a main body assembly which is separated and supported above the track by a special suspension arm. A motor is located in the body assembly, and a drive train is connected between the motor and track. The drive train extends through the suspension arm. The steering control system also passes through the suspension arm and causes the track to flex laterally into a curve in a manner which positions the rider over the flotation centerline of the curved track and thereby maintains balance while negotiating turns. One end of the suspension arm is sprung from the track, and the body is sprung from the other end of the suspension arm.

Abstract: A improved stabilizer construction for a snowmobile wherein the front skis are supported for suspension movement and for steering by means of a scissors type link. The stabilizing arrangement includes a torsion bar that is affixed for rotation with the pivotal connection of the scissors linkage to the steering arm of the front skis.

Abstract: Apparatus is disclosed for adjusting the steering column and handlebars of a snowmobile. The steering column has upper and lower sections, pivotable with respect to one another about a first lateral axis. A first pawl and cylinder, mounted respectively to the upper and lower sections, rigidly connect these sections when engaged, but permit these sections to pivot relative to each other when the pawl is retracted from the cylinder. A second pawl and cylinder are mounted at the top of the steering column upper section and rigidly connect the upper section and handlebars. Retraction of the second pawl from engagement with the second cylinder frees the handlebars for rotation, relative to the upper steering column section, about a second lateral axis parallel to the first axis. A single lever, pivotally mounted to the column upper section, has a cam which engages and retracts the first and second pawls simultaneously, for maximum ease in steering system adjustment.

Abstract: A snowmobile embodying a flexible flap that depends from the rear of the snowmobile body to prevent snow thrown from the driving tread from impinging upon the rear of the snowmobile and its riders. In addition, a permanent, rigid guide extends around the rear of the snowmobile body and rearwardly a sufficient distance to protect the snowmobile and riders from snow in the event the flap deflects during snowmobile operation.

Abstract: A suspension arrangement for the steering skis of a snowmobile that permits soft ride through high suspension travels while at the same time prevents roll during cornering. The suspension system includes an element that is moveable with each of the skis during its suspension travel but which does not rotate with the ski during steering. Each of these respective elements is coupled to a torsion bar for loading the torsion bar upon relative vertical movement between the skis so as to resist body roll.

Abstract: A steering system for vehicles, for example snowmobiles. A strut-type suspension includes a fixed tube mounted to the chassis and a movable tube axially reciprocable in the fixed tube. A collar is mounted to structure attached to the chassis, and is rotatable around the axis of the movable tube. A scissors type linkage interconnects the collar and a ski, or a mount for a ski, or the movable tube. Preferably the collar includes an arm which extends rearwardly into the vehicle body.

Abstract: A motorcycle having a body carried on front and rear power-driven wheels in which the wheels are provided with novel tread design cooperating with the body and portions thereof to literally pump water rearwardly while confining it to ridge or crest form centered on the longitudinal centerline of the vehicle whereby to enable the vehicle to travel over water. The body is closed at its top, opposite sides and also at its front and rear ends by front and rear fender wells, respectively, creating an air chamber beneath which the front wheel pumps water to flow rearwardly as aforesaid.

Abstract: A snowmobile ski suspension comprises a telescopic strut formed from a fixed support tube and a guard tube reciprocably and swivelly mounted in the guard tube. The support tube is fixed to one end of a crossbar of the snowmobile frame. Steering of a ski attached to the bottom of the guard tube is accomplished by rotating a bifurcated steering arm, which is journaled on the support tube so as to straddle the crossbar, the steering motion being transferred to the ski by a hinge connected between the steering arm and the ski. A shock absorber and a coil compression spring are mounted in the strut and act to resist collapse of the latter.

Abstract: A mount for pivotally joining the steering ski of a snowmobile to an extendible-retractible movable tube of a strut-type suspension. The joinder is made by a pivot pin which extends laterally to, and is offset from, the movable tube. Preferably the tube is disposed at an angle to the vertical, and the pivot pin is behind the movable tube. The ski and pivot pin can be removably mounted to the end of the movable tube by a gusset which itself can be attached to and removed from, the movable tube.

Abstract: The steering ski of a snow vehicle such as a snowmobile, is mounted to the lower end of a downwardly-extending support member such as a strut. The ski is mounted by a bearing which enables it to be rotated for steering purposes independently of the support member, thereby reducing the complexity of the assembly and facilitating steering.