Editing Kart racing (section)

=== Transmission ===
Purpose of transmission: There are three reasons for having a transmission in the automotive power train or drive train. The transmission can:
* Provide torque needed to move the vehicle under a variety of road and load conditions. It does this by changing the gear ratio between the engine crankshaft and vehicle drive wheel.
* Be shifted into reverse so the vehicle can move backward.
* Be shifted into neutral for starting the engine and running it without turning the drive wheels.<ref>{{Cite web|url=http://oaji.net/articles/2017/1992-1530703509.pdf|title=Design of Transmission System for Go-Kart Vehicle}}</ref>

Karts do not have a [[differential (mechanical device)|differential]].<ref name="chassis" /> The lack of a differential means that one rear tire must slide while cornering. This is achieved by designing the chassis so that the inside rear tire lifts up slightly when the kart turns the corner. This allows the tire to lose some of its grip and slide or lift off the ground completely.

Power is transmitted from the engine to the rear axle by a chain. Both engine and axle [[sprocket]]s are removable. Their ratio must be adapted to the track configuration to obtain the most performance from the engine.

In the early days, karts were direct drive, requiring push starts. The inconvenience of that configuration led to the [[centrifugal clutch]] for the club level classes. Dry centrifugal clutches are now used in many categories; [[Rotax Max]] is one example. They have become the norm as the top international classes have switched to 125&nbsp;cc clutch-equipped engines as of January 2007.