Formula One glossary

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MacPherson strut

A suspension piece which employs a coil spring and shock absorber attached to the lower A-arms and the top of the front body structure. Originally it had a lateral link with an anti-roll bar instead of the lower A-arm. It was first invented by a Ford of England engineer, Earle S. MacPherson.

Main shaft

The transmission output shaft


Engine management programme which defines optimum air/fuel mixture and ignition timing depending on engine speed


Marshals are positioned at many places around the race circuit, their job is to look after safety. This includes moving cars from unsafe positions and alerting drivers to on track hazards by waving various coloured flags.


The metre, or meter, is the basic unit of length in the International System of Units (SI: Système International d'Unités). It is defined as the length of the path travelled by light in absolute vacuum during a time interval of 1/299,792,458 of a second. It is equal to 10000/254 inches, approximately 39.37 inches. The symbol of the metre is m.


An alcohol that is occasionally blended with gasoline (typically 3%) to raise octane levels, it is poisonous to humans and causes trouble with rubber and plastic parts of the fuel system not designed to handle alcohol-blended fuels. Also called "methyl alcohol" or "wood alcohol". This alcohol was used as fuel in the former CART series.


The failure of the fuel charge in one or more engine cylinders to fire or ignite at the proper time. It can be due to poor compression caused by worn or improperly adjusted valves, worn piston rings, a faulty head gasket, or in the case of a two-stroke engine leaking crank seals. It can also be caused by poor ignition due to worn or dirty spark plug electrodes, worn or improperly gapped points or spark plugs, poor fuel delivery, faulty ignition wiring, or faulty distributor components.


A unit of metric measurement indicating the size of the pitch of a gear.
It relates to the ratio of the pitch diameter to the number of teeth, thus the module of a gear = pitch diameter (in millimetres) divided by the number of teeth in the gear.
Module pitch is an actual dimension, whereas Diametral Pitch is only a ratio.
Normal Module: This is the value of the module in the Normal Plane, usually measured on the pitch line. see diagram. The calculation of the normal module is shown below.
Transverse Module: This is the value of the module in the Transverse Plane, usually measured on the pitch line. See diagram. The calculation of the transverse module is shown below.

Moment of inertia

This is similar to inertia except that it relates to rotating movement rather than linear movement. Linear movement is the tendency of an object to remain motionless if at rest and to keep moving in a straight line if already in motion. The moment of inertia, however, is the tendency of an object to resist being accelerated when it is rotating. The polar moment of inertia is the rotating movement around a vertical axis through the center of rotation. It greatly affects steering and handling response in an automobile. The greater the length of the axis the greater the polar moment of inertia. By having the heavy components of a vehicle such as the engine and transmission between the two front wheels, the polar moment of inertia is low so that the tires can easily change the direction of the vehicle.

Monkey Seat

Technically, this is the Y75 wing. It is a small wing, which is situated above the rear beam wing and directly behind the coke bottle region.


French word (one shell) describing the single-unit construction of a modern racing car chassis which basically needs to protect the driver in case of crashes

Motor Generator Unit - Heat (MGUH)

A Heat Motor Generator Unit is a term used by the FIA for an electrical machine linked to the exhaust turbine of a pressure charging system as part of an energy recovery system.

Motor Generator Unit - Kinetic (MGUK)

A Kinetic Motor Generator Unit is an electrical machine mechanically linked to the drive train as part of an energy recovery system (ERS).


Bosch tradename to denote its engine management systems. The original Motronic system combined L-Jetronic with electronic ignition timing control in one control unit. Most Motronic-equipped engines also have electronic idle stabilization. Around 1986, Motronic system got knock regulation by ignition timing of individual cylinders; adaptive circuitry, which adapts fuel delivery and ignition timing to actual conditions; diagnostic circuitry which enables the control unit to recognize system faults and store fault information in its memory. Motronic has also been integrated with KE-Jetronic system and is referred to as KE-Motronic

Multi-link suspension

A rear suspension consisting of at least four links, or "arms", and no struts. Because multi-link suspensions assign specific wheel-locating duties to each element, they provide great flexibility for optimizing both ride and handling.
More at wikipedia

Multiple disc clutch

A clutch which has several clutch discs in its construction. The greater number of discs allows the size of the bell housing to be smaller in diameter and still maintain efficiency. A clutch with more than one driven plate, usually of the oil-immersed type; frequently used in motorcycle drive trains, in automatic transmissions of cars, in power distribution systems of 4WD vehicles, and as locking elements in limited-slip differentials.