A final transmission/transaxle gear ratio of less than 1:1 that is designed for economical highway driving. The overdrive gear allows the engine to operate at lower rpm while maintaining the given vehicle speed, thus requiring less fuel because the engine is doing less work.
Any gearset in which the output shaft turns faster than the input shaft. Overdrive gears are used in most modern transmissions because they reduce engine rpm and improve fuel economy. Occasionally, a separate gearbox with an overdrive gearset is coupled to a conventional transmission.
Supplementary transmission mounted between a gearbox and final drive. It raises the drive shaft's speed of rotation relative to the gearbox output shaft, changing the final drive ratio.
A user -installable microprocessor from Intel for the 486 microprocessor. Many PCs 486-based PCs were built with an “OverDrive” socket, which allowed a processor upgrade simply by inserting a faster OverDrive chip.
It is the secondary gearbox which provides an additional gear ratio. It allows the drive shaft to turn faster than the engine crankshaft. Overdrive gears reduce engine rpm and improve fuel economy at highway speeds.
Refers to a condition in which the vehicle's transmission is in a gear having a ratio greater than 1:1, that is, the engine crankshaft turns at a slower rate than the vehicle drive shaft. Opposite of under drive. (Also see direct drive).
A gear set in which the output shaft rotates faster than the input shaft.
Generally a small auxiliary gearbox, usually mounted behind the car's main gearbox or attached to the differential, giving another gear in addition to the other three or four speeds in the main transmission. Overhead Cam A camshaft located above the cylinder head or heads instead of in the cylinder block.
a top gear that is higher than 1:1. Originally overdrives were only provided as optional units bolted onto the original gearbox, and often employing epicyclic gears. The term is now also applied to the top (usually 5th) gear ratio in the main gearbox when it is higher than 1:1.
a high gear used at high speeds to maintain the driving speed with less output power
drive or work too hard; "The teacher is overworking his students"; "Overdriving people often suffer stress"
a mechanical unit bolted to the rear of the transmission
A gear ratio designed for most transmissions that allows the driveshaft to turn faster than the crankshaft, resulting in higher road speeds with less engine effort and fuel consumption.
A final transmission gear ration that is designated for economical highway driving. It allows the engine to run at lower r.p.m. while maintaining the given vehicle speed, thus requiring less fuel. It changes the effective drive ratio.
A fuel-saving device, overdrive is an extra gear on a manual or automatic which makes the engine turn more slowly at higher road speeds. It's called overdrive because the driveshafts are turning faster than the engine.
A device coupled to a car's gearbox which raises the output gear ratio above the normal 1: 1 of top gear.
A processor upgrade sold by Intel that is used to upgrade an older processor to a newer, faster processor.
A gear assembly which produces more shaft revolutions than that transmitted to it.
A transmission ratio below 1:1. For instance, a manual transmission fifth gear ratio could be 0.70:1. Overdrive ratios improve fuel economy by reducing engine RPM at highway speeds.
Refers to the transmission’s highest gear; allows for efficient cruising Read more
An optional special gear that allows the rear wheels to turn faster than the engine. This lowers fuel consumption during sustained high-speed driving on freeways.
A transmission in which the highest gear ratio is less than a one-to-one ratio. This means the drive shaft turns faster than the engine crankshaft. The overdrive feature saves fuel and, because the engine runs slower, engine wear and noise are reduced.
Gearing in which less than one revolution of a transmission's input shaft causes one turn of the output shaft. The purpose of overdrive is to reduce engine rpm in high gear for better fuel economy. Example: A transmission with an overdrive top gear has a ratio of 0.70 to one. Turning the input shaft 0.7 revolutions causes 1.0 revolution of the output shaft.
This is the highest gear in a transmission that is used for reasons of fuel economy when at cruising speed (and not to make the car go faster, as is quite widely believed).
An interchangeable term for back drive.
A transmission gear with a ratio below 1:1, which improves fuel economy by reducing engine revolutions per minute at highway speeds. On a five-speed manual transmission, the fourth and fifth gears are overdrive. On a four-speed automatic transmission, the fourth gear is overdrive. When an overdrive gear set is engaged, the output shaft turns at a higher rate than the input shaft, reducing engine revolutions at cruising or highway speeds.
A transmission having a ratio of less than 1:1 where the output shaft turns at a greater rpm than does the input shaft.
reduces engine rpm for any given road speed. Reduces engine wear and noise, and increases fuel economy.
A type of main or auxiliary transmission which permits output shaft speeds in excess of input speeds. These type transmissions are only used with single-speed axles and are recommended for operation only when the vehicle is empty or lightly loaded.
Overdrive can refer to two different things. An overdrive is a device which was commonly used on rear-wheel drive automobiles to allow the choice of an extra-high overall gear ratio for high speed cruising, thus saving fuel, at the cost of less torque.
Overdrive in the field of rock music, is a term used for an electric guitar amplifier when turned up, usually deliberately, to the point where distortion (clipping) is clearly audible in the output signal. This distortion may range from a slight added "edge" with some increase in sustain, up to a thick fuzzy sound whose tonality is almost unrecognisable as that of the input signal.