Bicycle brake brakes are slightly heavier than conventional side-pull calipers and cannot accurately track an out-of-true rim, or a wheel that flexes from side to side in the frame during hard climbing. It is common to see professional racers climbing mountains with the quick-release undone on the rear brake, to eliminate drag from this source. This type of brake has symmetrical arms and therefore centre more effectively. The cable housing attaches to a fixed cable stop attached to the frame, and the inner cable bolts to a sliding piece (called a "braking delta", "braking triangle", or "yoke") or a small pulley, over
The purpose of a system is what it does The purpose of a system is what it does The purpose of a system is what it does (POSIWID) is a systems thinking heuristic coined by Stafford Beer. Stafford Beer coined the term POSIWID and used it many times in public addresses. In his address to the University of Valladolid, Spain, in October 2001, he said "According to the cybernetician, the purpose of a system is what it does. This is a basic dictum. It stands for bald fact, which makes a better starting point in seeking understanding than the familiar attributions of good intention, prejudices about expectations, moral judgment,