Automotive Technical Terms

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Throughout this site we use many technical terms, and given the breadth of readership our site enjoys, sometimes we are remiss and incorrectly assume everyone knows what we are referring to. For those that do not, here are some explanations of the technical terms use.


A style of car body design that has no B pillar between the doors and roof.


A British unit of power, used to define the rate at which work is done. Has been replaced by the kilowatt, and an approximate conversion is 100hp = 75kW.

Hydraulic Damper:

A shock absorber whose damper action results from hydraulic flow through precisely machined orifices.

Independent Suspension:

A type of vehicle suspension where the movement of one wheel does not necessarily result in the movement of the other wheel, because the wheels do not share a common axle. It is often abbreviated to IFS for “Independent Front Suspension”, and IRS for “Independent Rear Suspension”.

Inertia Reel Seatbelt:

A seat belt location method that allows the belt to pull in and out by a spring-loaded reel set-up as the occupant wishes, but on sudden forward movement (ie: in a collision), the reel locks, thus securing the occupant.


Inclined steel pivot in steel housing that allows front wheels to turn side to side as well as move up and down. Generally replaced by a pair of ball joints on most modern cars.

Laminated windscreen:

A windscreen that is fabricated from two or more layers of glass joined by a clear plastic layer, which is more resistant to impact by flying stones than a conventional windscreen.


Also landaulette. Enclosed car with folding rear roof. Originally chauffeur-driven with a fixed or movable partition between front and rear seats.

Live axle:

Conventional rear axle set-up that contains rotating drive shafts. The actual term 'live' refers to the fact that the axle transmits power as opposed to a dead axle whose sole function is suspension.

Mag wheel:

This term originally referred to a wheel cast in magnesium or a magnesium alloy, but now is a more loosely defined term that refers to any cast wheel.


The grouping of pipes that distribute the inlet charge from the carburetor to the various cylinders and likewise the exhaust gases from the various cylinders to the exhaust system.


Imperial system of measuring fuel consumption. Now replaced by liters per 100 kilometres.


Refers to the content of various hydrocarbon groups in petrol. An approximate measure of the inherent combustion energy found in a given petrol type.


A device for recording the total distance covered by the vehicle. Driven off the speedometer and usually located in the speedometer face.


Refers to a gearbox ratio where the output shaft turns faster than the input shaft. Most gearbox ratios decrease shaft speed while an overdrive ratio increases shaft speed. It provides more relaxed cruising ability and reduced fuel consumption by lowering engine speed relative to road speed.

Overhead Camshaft:

Abbreviated OHC. A specific type of cylinder head design where the camshaft is located above the valve gear.

Overhead Valve:

Abbreviated OHV. Refers to design where the valves a above the combustion chambers but are actuated through pushrods by a camshaft located below the cylinder head.


Handling characteristic of a vehicle that refers to the tendency for the rear wheels to run wide in a corner, thus steering the front of the vehicle increasingly into a corner.
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