What is Differential (mechanical device)?
[[File:Differential gear (PSF).png|thumb|right|250px|{{Center|Line art diagram of a differential gear. (1) [[Ring gear]], (2) [[Pinion]]s, (3) [[Pinion shaft]], (4) Drive pinion, (5) Right [[axle]], (6) Side [[gear]]s, (7) Left axle}}]] A '''differential''' is a mechanical device made up of several [[gear]]s. It is used in almost all mechanized four-wheel vehicles. It is used to transmit the power from the [[driveshaft]] to the drive wheels. Its main function is to allow the drive wheels to turn at different [[Revolutions per minute|rpms]] allowing the wheels to go around [[wikt:corner|corner]]s while still receiving power from the engine.<ref name=learneng>{{cite web |url=http://www.learnengineering.org/2014/05/working-of-differential.html |title=How does a Differential work ? |publisher=Learn Engineering |access-date=13 May 2016 |archive-date=8 May 2016 |archive-url=https://web.archive.org/web/20160508204212/http://www.learnengineering.org/2014/05/working-of-differential.html |url-status=dead }}</ref> == Different types == * An '''open differential''' (OD) is the most common type. It is also the least expensive. An open differential allows the vehicle to go around corners without dragging the outside wheel. However, power is transferred to the wheel with the least amount of traction (grip on the road). If that wheel is on [[ice]] or other slippery surfaces, the vehicle will not move forward and the wheel with the power will simply spin. In vehicles with [[two-wheel drive]], if they have an open differential in effect they have only a single drive wheel. In [[four-wheel drive]] vehicles using open differentials (usually standard from the factory), only one wheel on each [[axle]] powers the vehicle. Advantages include seldom breaking an axle, less [[tire]] wear, and they are [[wikt:free|free]] as most new vehicles come with open differentials.<ref name=kennedyFWN>{{cite web |url=http://www.fourwheeler.com/features/131-0404-4x4-differentials-open-diff-vs-spool/ |title=Open Differential vs Spool - Differential Dif