Improved skateboards and methods of obtaining or providing skateboards with improved trucks. Trucks have two axles or axes, two primary wheels, and two secondary wheels, and skateboards have eight wheels, four in front and four at the rear portion of the skateboard. The four primary wheels support most or all of the weight of the skateboard when the skateboard is on a flat surface, and the two secondary wheels support the weight of one portion of the skateboard (e.g., front or rear) when the primary wheels cross a crack (e.g., a sidewalk contraction joint). In various embodiments, the secondary wheels are located outboard of the primary wheels. Further, in a number of embodiments, the axis of rotation or axle of the primary wheels remains parallel to that of the secondary wheels, whether the skateboard is going straight or turning.

To provide inline skates that prevent skidding when curving and turning, and enable stable curving turns to be performed while maintaining straight running speed. An inline skate has a plurality of running wheels arranged in a row in series in the running direction. Wheel shafts of curving wheels have axial directions that are orthogonal to the axial directions and running directions of the wheel shafts of the running wheels, respectively. When the inline skate is upright, ground surfaces of the plurality of curving turn wheels are located at a position higher than the sliding surface and on both sides of the inline skate.

An apparatus comprising a platform and a plurality of trucks coupled to the platform. The trucks are longitudinally opposing each other. The apparatus further comprising a plurality of roller assemblies coupled to the platform. The assemblies are longitudinally opposing each other between the trucks. The assemblies are configured for omnidirectional rotation. The assemblies are elastically biased for longitudinal alignment. At least one of the assemblies comprises a motor.

A summer style ski having three different types of wheels aligned to allow the ski to travel on non-snow or ice surfaces and to create the feel of carving or turning on a paved surface.