A shift knob also known as a gear knob, gear shift knob and stick shift knob is the physical interface between the manual transmission

Manual transmission

A manual transmission, also known as a manual gearbox or standard transmission is a type of transmission used in motor vehicle applications...

 stick shift and the drivers hand. Made of many materials from simple plastics through to platinum

Platinum

Platinum is a chemical element with the chemical symbol Pt and an atomic number of 78. Its name is derived from the Spanish term platina del Pinto, which is literally translated into "little silver of the Pinto River." It is a dense, malleable, ductile, precious, gray-white transition metal...

 it comes in many shapes sizes and weights. Generally spherical in shape the OEM

OEM

OEM means the original manufacturer of a component for a product, which may be resold by another company.OEM may also refer to:-Computing:* OEM font, or OEM-US, the original character set of the IBM PC, circa 1981...

 versions tend towards the conservative and the automotive aftermarket versions can be found to be of very original design.

The shift knobs' principal function is the ergonomical interface between driver and the manual transmission stick shift. The stick shift, as the name implies, is often just a machined or cast aluminium

Aluminium

Aluminium or aluminum is a silvery white member of the boron group of chemical elements. It has the symbol Al, and its atomic number is 13. It is not soluble in water under normal circumstances....

 or steel

Steel

Steel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...

 rod with or without threading the shift knob is fitted on its end.

In recent years manufacturers have increased the variety of shifts knobs available to the consumer from inexpensive plastics to diamond studded white gold.

Weighted shift knobs

A weighted shift knob is a performance driven aftermarket modification which entirely replaces the OEM shift knob and sits atop the aftermarket short shifter

Short shifter

A short shifter, also known as a short throw shifter, is the result of an automotive aftermarket modification of the manual transmissions' stick shift either by modification of the existing stick shift or, alternately, by the replacement of the entire part.The purpose of the modification is to...

 or OEM manual shift stick. Initially designed to be used in tandem with a short shifter

Short shifter

A short shifter, also known as a short throw shifter, is the result of an automotive aftermarket modification of the manual transmissions' stick shift either by modification of the existing stick shift or, alternately, by the replacement of the entire part.The purpose of the modification is to...

, it is increasingly being purchased for stock stick shifts. The weight generally varies between 400 and 600 gram

Gram

The gram is a metric system unit of mass....

s or more, depending on the material used. The principle of the weighted shift knob is to make the stick shifter top heavy, thus increasing the available leverage in order to decrease time between shifts. Weighted gear knobs are offered for sale by a variety of North American based manufacturers in many shapes and finishes, though they are significantly more expensive than the commonly available aftermarket

Aftermarket (automotive)

The automotive aftermarket is the secondary market of the automotive industry, concerned with the manufacturing, remanufacturing, distribution, retailing, and installation of all vehicle parts, chemicals, tools, equipment and accessories for light and heavy vehicles, after the sale of the...

shift knob.