An electric bicycle includes: a sleeve to which power for driving the electric bicycle is input; a rear wheel; and a power transmission mechanism that transmits the power input to the sleeve to the rear wheel. The electric bicycle determines an abnormality of the power transmission mechanism or prevents or prohibits driving performed by using the power transmission mechanism based on a reference composite gear ratio of the power transmission mechanism acquired at a first time and current composite gear ratio of the power transmission mechanism acquired at a second time subsequent to the first time.

A stroller track system is used to facilitate the transporting of a stroller up and down stairs. The stroller track system includes a stroller, a left tread assembly, and a right tread assembly. The left tread assembly and the right tread assembly are mounted to a frame of the stroller and are used to engage multiple stairs while traversing a set of stairs. This allows the stroller to glide smoothly up or down the stairs. The left tread assembly and the right tread assembly each include a first track and a second track. Together, the first track and the second track allow the left tread assembly and the right tread assembly to span a larger section of a staircase. The first track is mounted to the frame through a first stroller-attaching mount. A track-securing bracket is used to mount the second track to the frame.

A rotating binding for a snowboard or other recreational equipment to which a user's foot is attached includes a lever having teeth at one end for engaging corresponding teeth in a disk attached to the snowboard or other equipment. Movement of the lever is resisted until an additional movement of the lever is performed in order to unsecure the lever from a secured position in which it engages the teeth within the disk. Some examples of the snowboard or other recreational equipment may include retractable fins that may be extended downward from the snowboard, or secured in a retracted position.

A stroller track system is used to facilitate the transporting of a stroller up and down stairs. The stroller track system includes a left tread assembly and a right tread assembly. The left tread assembly and the right tread assembly are used to engage multiple stairs while traversing a set of stairs. This allows the stroller to glide smoothly up or down the stairs. The left tread assembly and the right tread assembly each include a first track and a first stroller-attaching mount. The first track has a greater surface area than a normal wheel, allowing the first track to span a larger section of a staircase. The first stroller-attaching mount is used to attach the first track to a stroller. In alternative versions of the stroller track system, the left tread assembly and the right tread assembly may include additional tracks to further stabilize the stroller.