Abstract: A lock system can be provided at each rear wheel assembly of a four wheel steering system to physically lock the rear wheel assemblies in a fixed direction to safely prevent rear wheel steering when such feature is undesirable. The lock system can use an electronically controlled actuator to hydraulically drive or retract a lock cylinder to lock or unlock the rear wheel assemblies, respectively. Sensors can be used to detect whether the lock cylinders are driven or retracted by their respective actuators, so that a controller monitoring the sensors can determine whether four wheel steering is enabled or disabled.

Abstract: A bicycle handlebar/stem/steering tube assembly has a handle bar diameter and a steering tube diameter there-within. One or both of the steering tube and the handlebar includes one of a depression, a diameter-reduction, and a through-hole configured to mate rigidly against the other of the steering tube and the handlebar and be affixed thereto by the stem at a handlebar/steering tube interface such that a stem offset is created of a dimension that is less than either the handlebar diameter and the steering tube diameter at the handlebar/steering tube interface.

Abstract: A caliper brake for a bicycle comprising left and right caliper arms rotatably fitted to a pivot shaft and having at their ends brake shoes adapted to be urged against a rim of a wheel of the bicycle, a rocking arm having a base portion pivotally mounted to a frame of the bicycle between the caliper arms on the pivot shaft in a semi-fixed condition, and the rocking arm having at its end a through-hole, opposite to which the left and right caliper arms have bottomed holes, respectively, and a universal joint lever having at its middle portion a middle protrusive ball portion and at both its ends end protrusive ball portions, respectively, the middle protrusive ball portion fitting in the through-hole of the rocking arm, those end protrusive ball portions fitting in the bottomed holes of the left and right caliper arms, respectively, whereby the extent of the free gaps between the left and right brake shoes and the rim are maintained substantially equal.