singlepivot

Singlepivot is a term used in mechanical design to describe a linkage or mechanism in which the motion of moving parts is governed by a single fixed pivot point. In its simplest form, a single-pivot assembly consists of a rigid frame with one fixed pivot to which one or more links are attached; as the connected links rotate about this pivot, other points on the mechanism trace out prescribed motions.

In practice, the phrase is commonly applied to bicycle rear-suspension designs known as single-pivot suspensions. In these systems, the rear swingarm is mounted to the main frame at a single pivot, and wheel travel results from the rotation of the swingarm around that pivot. This arrangement offers a compact, lightweight solution with relatively few joints and straightforward maintenance. Its main advantages are simplicity, stiffness, and ease of manufacturing; it often yields predictable steering and geometry when correctly configured.

Drawbacks include limited control over the wheel path during compression, pedal kickback and reduced anti-squat modulation compared with multi-link designs, and greater sensitivity to chain growth and frame geometry as suspension compresses. Designers sometimes mitigate these issues by mounting the shock in specific positions, tuning leverage curves, and choosing pivot locations carefully.

Beyond bicycles, single-pivot configurations are used in certain robotic arms and other planar linkages where a single rotary joint provides the required motion. They are contrasted with multi-link mechanisms that use two or more pivots to shape motion more flexibly.