US Patent 8382136 Bicycle rear suspension system linkage

A bicycle rear suspension system includes a main frame and a rear wheel suspension system. The main frame generally comprises a seat tube, a down tube, a top tube, and a head tube. The rear wheel suspension system comprises a first linkage member, a rear wheel swingarm, and a second linkage member. The first linkage member is shorter than 15 mm from its pivotal connection to the main frame and its pivotal connection to the rear wheel swingarm, and changes its direction of rotation as the rear wheel is articulated generally vertically. The rear wheel suspension system allows for a preferential rear wheel axle travel path that provides for increased rates of chainstay lengthening in the first part of the vertical rear wheel travel with a rapid change to reduced chainstay lengthening in the latter part of the vertical rear wheel travel so that the overall change in chainstay length is small relative to the amount of vertical rear wheel travel.