DICTIONARY OF AUTOMOTIVE TERMS - "Gr"

Grab:

1. The action of brakes to seize the drum or disc suddenly when the brake pedal is pressed.
2. The action of a clutch to take up the drive suddenly when the clutch pedal is released. Also called "snatch."

Also See:
fierceness

Grabber:

See:
webbing grabber

Grab handle:

1. A strap or part of a car door interior used to pull the door shut. Also called "door handle."
2. An inside strap located above the door which is used to steady a passenger during sharp cornering. At one time this handle was found only on the passenger side; but in newer cars it is also on the driver's side.
3. A handle on the tongue of a trailer, used to move the trailer manually

Grade:

1. The steepness of the road on a hill expressed as a percentage. Example: A vehicle climbing a 8% grade rises 8 feet for every 100 feet of forward travel.
2. The composition of gravel and rock, etc. of a road surface (thus the vehicle used to smooth it is a grader).
3. The strength factor of a fastener (i.e., nuts and bolts). In US fasteners, grade 2 has a tensile strength of 60,000 psi; grade 5 = 120,000 psi; grade 7 = 133,000 psi; grade 8 = 150,000 psi; grade ASTM A574 = 170,000 psi. In metric fasteners, grade 4.8 = 60,900 psi; grade 8.8 = 120,350 psi; grade 9.8 = 130,500 psi; grade 10.9 = 150,800 psi; and grade 12.9 = 176,900 psi.
4. The quality of oil. See oil grade.
5. A British term for the degree of sandpaper coarseness. The US term is grit.

Gradeability:

A vehicle's ability to climb a grade at a given speed. Example: A truck with a gradeability of 5% at 60 mph can maintain 60 mph on a grade with a rise of 5%.

Grader:

A road construction vehicle with a large blade which scrapes gravel to smooth or level a surface. Graders are also used to remove snow from roads.

Gradient:

1. The slope or inclination of a road
2. A measure of the slope, expressed as the ratio of height (or drop) to horizontal distance; a steep hill might be 1 in 4, while a gradual slope might be 1 in 10

Grading:

See:
quality grading

Graduated tint:

The tinted stripe at the upper edge of a windshield

Graft copolymer:

A copolymer in which polymeric side chains have been attached to the main chain of a polymer of different structure

Graham-Paige:

A vehicle brand of which only the Custom body of 1925-1948 with required application are classic cars.

Grain alcohol:

Ethanol

Grain coarsening:

Roughening of the surface of a material

Grain growth:

Roughening of the surface of a material

Grand Am:

A model of automobile manufactured by Pontiac division of General Motors
Click image for books on Grand Am

Grand Luxe:

(GL) A model that is more luxurious model than a standard model

Grand National:

A model of automobile manufactured by Buick
Click image for books on Buick Grand National

Grand Prix:

1. An international car race from which points are scored towards the World Championship.
2. A model of automobile manufactured by Pontiac division of General Motors

Click image for books on Pontiac Grand Prix

Grand Touring:

(GT) A term used for a sportier car.
Also See:
Gran Turismo.

Grand Touring-injection:

(GTi) A GT car with fuel injection.

Grand Touring Prototype (GTP):

See:
camel Grand Touring Prototype

Granny gear:

Colloquial term for the smallest inner chainring on a triple chainring crankset of a bicycle. Needed for climbing steep hills especially with a loaded bicycle.

Gran Turismo:

(GT) A car which combines the features of both the sedan and sports car. It features excellent engineering and road handling with relative comfort. Made in two-seater and four-seater models with cramped rear seats.

Graph:

A diagram showing the relationship between certain numbers or quantities in the form of a line

Graphic display unit:

A dashboard panel displaying a plan of the car with illuminated parts representing doors left open, lights switched on, etc.

Graphic equalizer:

A unit in a car stereo system that adjusts the audio output signal strength separately for individual frequency ranges; individual frequencies can be emphasized to compensate for specific acoustic conditions

Graphics:

See:
splashed graphics

Graphite:

A form of carbon used in making brushes for motors and generators and as a lubricant

Graphite grease:

Heavy-duty grease containing graphite, used for brake cables, etc.

Graphitic corrosion:

Selective corrosion of grey cast iron, resulting in preferential removal of metallic constituents, leaving graphite

Grass:

Trucker slang for the median strip or side of road as in "We got a four wheeler broke down in the grass at the 211 yardstick."

Grass heat shield:

A metal shield fitted underneath a catalytic converter to reduce the risk of its heat starting an accidental grass fire

Gravel:

A mixture of rocks and sand where the rocks are usually less than 1 inch (25 mm) in diameter.

Gravel gun:

Equipment used to hurl crushed stone at objects, such as test panels, to test them for chipping resistance

Gravel road:

A road which is covered with a layer of gravel. Also called a secondary road or an improved road.

Graveyard:

See:
auto graveyard

Gravity:

The attractive force exerted by one body on another. All bodies which have mass have this property. The pull of the earth upon objects so that they fall at the rate of 981 cm (32.2 feet) per second every second.
Also See:
center of gravity
g
specific gravity

Gravity bleeding:

A method of purging air from a hydraulic system by allowing the fluid to force air out of an opened bleeder valve by its own mass.

Gravity, center:

The force which causes a body to fall to the earth.
Also See:
center of gravity.

Gravity feed:

A fuel supply system where the gas tank is mounted higher than the carburetor. This system was used in some older cars where the gas tank was located in front of the windshield and in many motorcycles.

Gravity-feed spray gun:

A type of paint spray gun, in which paint flows downward from a container mounted on its top, thus reducing the amount of compressed air required

Gray Market Vehicles:

Cars that have been imported into the country through unauthorized means. It is likely they won't meet American safety and emission standards. These cars have significantly lower values than vehicle imported through normal channels.

Grease:

1. A lubricant (made from oil and metallic soaps) which reduces the friction between moving pieces of metal and also prevents moisture from causing metal to rust.
2. To lubricate or coat with grease.

Also See:
base grease
dielectric grease
differential grease
gear grease
gear grease
graphite grease
lithium base grease
lithium grease
lube grease
lube grease
white lithium grease.

Grease fitting:

A device that seals in and allows the addition of more grease, or some other type of lubricant, to cushion two moving parts, allow them to move freely, and prevent them from wearing each other away. Found on ball joints, steering knuckles, tie-rod ends. Also called "zerk fitting."

Grease gun:

A small, hand-operated pump that can be loaded with grease and used for lubricating the grease fittings on a vehicle. Adapters can be attached to the grease gun so that grease can be forced even into sealed bearings.

Grease nipple:

A small, one-way valve used for injecting grease into a bearing

Grease pencil:

A writing device which writes in grease or wax. It is used to mark tires because it can be easily rubbed off.

Grease seal:

A circular metal disk covered in rubber or plastic with a center hole, an edge on the outside circumference, and another edge on the center hole with a spring to retain tension on the shaft that fits into the hole. It is used to keep grease and oil from leaking out and protects bearings from dirt and water. Also called "oil seal."

Great Lakes ship:

Cargo ship used to carry cargo on the Great Lakes. Most carry bulk cargoes of grain, iron ore or coal.

Green:

See:
British Racing Green

Green flag:

A green flag is used to start or restart the race. The pace car will pull off the track into pit lane and the race resumes. Note: the race cars do not come to a stop on the track at anytime, unless a red flag is thrown.

Green flag with yellow diagonal stripe:

The green flag with a yellow diagonal stripe signals a slower driver to move over on the track and let the leaders proceed. This usually occurs near the end of a race when the slower car is many laps behind. This flag is to ensure safety for the cars still racing for the win.

Greenhouse:

The glass area of a car or truck.

Greenhouse gases:

(GHGs) Group of gases which individually act to trap solar energy near the earth. GHGs for which emission levels have been estimated are carbon dioxide (CO₂), methane (CH₄), nitrous oxide (N₂O), sulphur hexafluoride (SF₆), carbon tetrafluoride (CF₄), carbon hexafluoride (C₂F₆) and hydrofluorocarbons (HFCs).

Green stage:

The initial hardening phase during which the resin or filler has hardened but has not yet set solid; this occurs immediately after the resin or filler has kicked (British: gone off).

Green stamp road:

Trucker slang for a toll road as in "Can anyone tell me if 76 is a greenstamp road?"

Green stamps:

Trucker slang for money paid in fines (dollars) as in "Looks like the chicken coops are collecting plenty of green stamps today."

Green tire:

The complete rubber/fabric/steel tire just before being cured.

Grey market:

The grey market describes the purchase by intermediaries of product which is not supplied to them by the "authorized" distribution channel of the supplier. Thus, a warehouse club in Canada that sells a stereo bought in the U.S. or elsewhere from other than the manufacturer is supplying grey market goods. While grey market products are frequently the same as would be available from conventional channels in Canada, the grey market assumes responsibility for service or repair where the manufacturer declines this support.

Grid:

The lead screen or plate to which the battery plate active material is attached.
Also See:
electric grid
lead-antimony grid
plate grid

Grid-controlled ignition system:

A microprocessor-controlled ignition system with electronic ignition timing by means of an ignition map stored in the control unit memory

Grid dolly:

A special shrinking dolly with a large, flat groove

Grill:

Alternate spelling of "Grille."

Grille:

A grating or crosswork of bars usually as an ornamental cover of the radiator which allows air to cool the engine.
Also See:
speaker grill
egg-crate grille
radiator grille surround
radiator grille
slatted grille

Grille face panel:

A metallic grating which surrounds the radiator. Also called a "grille panel."

Grille panel:

A metallic grating which surrounds the radiator. Also called a "grille face panel."

Grille surround:

See:
radiator grille surround

Grind:

To remove metal from an object by means of a revolving abrasive wheel, disc, or belt.
Also See:
valve grinding
valve seat grinding.

Grinder:

A device to remove metal from an object.
Also See:
angle grinder
bench grinder
brake shoe grinder
mini-grinder
suction valve grinder
valve grinder

Grinding:

The process of using a brake lathe and a power-driven abrasive stone to remove metal from drums to refinish their friction surfaces.
Also See:
valve grinding
valve seat grinding

Grinding compound:

See:
valve grinding compound

Grinding disc:

An abrasive disc

Grinding paste:

An abrasive paste used for reseating valves

Grinding tool:

See:
valve grinding tool

Grinding wheel:

An abrasive wheel used for grinding (usually a composite of hard particles in a resin filler)

Grindstone:

A rotating abrasive disc for rubbing away metal and for sharpening tools

Grip:

1. The adhesion of a tire to the road surface; important for roadholding and safe braking.
2. A rubber or rubber-like tube which fits on the end of a pipe (i.e., handlebars or a tool).

Also See:
hot grip
lateral grip
wet grip
mole grips
vice grips
vise grips

Grip channel:

A steel channel spot-welded to a vehicle body to keep rubber seals in place

Grip in the wet:

A vehicle's roadholding ability in the rain or on a wet surface

Grip wrench:

Locking pliers

Grit:

1. A measure indicating the sizes of the abrasive particles in a grinding wheel, usually expressed by a figure denoting the number of meshes per linear inch in a sieve through which the particles will pass completely.
2. Siliceous sediment, loose or indurated, the component grains being angular. Sometimes applied to a hard coarse-grained sandstone.
3. Hard particles, usually mineral, or natural or industrial origin, retained on a 200 mesh test sieve (76 μm).

Also See:
P grit numbers

Grit blasting:

1. A sandblasting process where grit is used to clean the metal surfaces and is available in various grades for coarse or finer blasting on thin steel.
2. A cleaning of the spark plug electrodes by bombarding them with abrasive particles

Grit number:

A classification of sand paper by fineness of the grit particles.
Also See:
P grit numbers

GRND:

Abbreviation for "ground"

Grommet:

1. A rubber or plastic ring (like a donut) with a slot around the circumference. It is placed into a hole in a metal plate so that the edge of the metal fits in the slot. In this way, the grommet protects a cable or pipe that passes through the hole.
2. Ring-shaped parts made of a third material that prevents problems when two other dissimilar materials come into contact. Plastic brake fluid reservoirs attach to metal master cylinders with rubber grommets

Groove:

1. A channel or gouge in metal (see piston ring groove) or in the tread of a tire.
2. Another name for a viable racing lane on the race track.
3. The space between the ridges of a bolt thread.

Also See:
cracking groove
oil groove
piston ring groove
piston ring groove cleaner
ring groove
tread groove

Groove cleaner:

See:
piston ring groove cleaner

Groove cracks:

Splitting or cracking of the rubber (undertread) at the base of the grooves, between tread ribs. Primarily caused by growth in textile casings.

Grooved compression ring:

A scraper-type piston ring

Groove insert:

See:
top ring groove insert.

Groove weld:

A welding rod fused into a joint which has the base metal removed to form a V, U, or J through at the edge of the metals to be joined.

Grooving:

The cutting of a tread design into tread rubber where a design does not already exist. Also altering an original design, i.e., cross-grooving to increase traction.

Grooving hammer:

A wide-nose peen hammer

Gross:

See:
tonnage gross

Gross axle weight rating:

(GAWR) A US maximum weight specified load capacity of an axle specified by the manufacturer. Includes both the weight of the axle and the portion of a vehicle's weight carried by the axle.

Gross bhp:

See:
SAE gross bhp

Gross combination weight:

(GCW) The total weight of a truck and trailer combination and its entire contents.

Gross Combined Weight Rating:

(GCWR) The maximum load rating—including passengers, cargo, and trailer—for a particular vehicle. A vehicle's GCWR will typically be higher than its GVWR, since gross vehicle weight ratings are determined by axle ratings, and a trailer has its own axles.

Gross horsepower:

See:
SAE gross horsepower

Gross Laboratory Horsepower

Tested horsepower of a "bare" engine without fan, water pump, alternator, exhaust system or any other accessories.

Gross margin:

The return an intermediary achieves on the selling price of the article. That is, if the intermediary buys a product for $1 and sells it for $1.50, the margin is calculated. For example, .50 divided by $1.50, or 33%.

Gross registered tons:

See:
tonnage

Gross ton:

2240 pounds. Also called "long ton."

Gross train weight:

Same as gross combination weight.

Gross vehicle weight:

(GVW) or (GVWR)Maximum legal weight at which a vehicle can be operated. The total weight of a fully equipped truck, and payload (cargo) and passengers.

Gross Vehicle Weight Rating:

(GVWR) Curb weight plus the payload. The most the loaded vehicle can weigh, generally determined by suspension system, tire size, and brake capacity. A vehicle's GVWR is usually displayed on a label on the door or door-latch pillar.

Ground:

(GND or GRND)

1. Terminal of battery that is connected to the metal framework of the vehicle so that the frame acts as a conductor of electricity. In North America, the negative terminal is grounded. In British terms, it is called "Earth."
   Also See:
   battery ground
   negative ground
   positive ground
2. A result of grinding.
   Also See:
   cam-ground piston.

Ground and polish:

To cut and polish a crankshaft bearing surface to precision specifications.

Ground clearance:

The vertical distance between level ground and the lowest fixed item on a vehicle (usually one of the differentials).

Ground clearance control:

A small lever near the park brake of cars with hydropneumatic suspension that allows ground clearance to be increased for crossing rough terrain or when changing a wheel

Ground clearance sensor:

An instrument that senses the distance between the ground and car (for self-levelling air suspension)

Ground connection:

A wire or other metal strip for connecting a component to the vehicle chassis or body

Ground contact area:

The contact patch of a tire

Ground effect:

The phenomenon that occurs when the airflow between a moving object and the ground creates downforce.

Ground electrode:

The side electrode of a sparking plug. The opposite is the center electrode triangular ground electrode

Grounding:

1. The action of a vehicle when some part of its undercarriage touches the ground (e.g., when going over a curb). In some cases the vehicle can become high-centered so that the vehicle is stationary because the driving wheels are no longer touching the ground.
2. Attaching a wire (such as from a tester) to a ground, a metal part of the engine or car body, or the negative terminal of a battery.
3. Contact of the bottom of a ship with the sea floor.

Ground piston:

See:
cam ground piston

Ground return:

The return path of an electrical circuit, provided by a ground connection. The British term is "earth return."

Ground strap:

A wire cable or braided wire strap to transfer electricity. It can be found between the engine block and the chassis because the engine is isolated from the chassis by rubber mounts. Also called battery strap.
Also See:
ground wire.

Ground wire:

The wire which goes from the negative post of the battery to the frame on negative ground vehicles. Another ground wire may be a thick wire or braided wire cable which connects the engine to the frame. Since many engines are rubber mounted, there may be no metal contact between the engine and the frame apart from the ground wire which may also be called the ground strap. In British terms, it is called "earth wire."

Group:

See:
plate group and groupo

Groupo:

All the drivetrain components (usually from the same company like Campagnolo or Shimano) needed to turn a bare frame into a complete bicycle (e.g., crank, chain, derailleurs, brakes, etc). Also called "group."

Group of seven:

(G7) seven industrial countries consisting of the United States, Japan, Germany, France, the United Kingdom, Italy and Canada, whose leaders have met at annual economic summits since 1975 to coordinate economic policies.

Growler:

An instrument used in testing starters, generator, and armatures.

Grown tire:

A tire that, with use, has slightly increased in size

Growth:

See:
tire growth
grain growth

GRP:

(fiber)glass reinforced plastic

GRRF:

Acronym for "Groupe de travail en matière de Roulement et de Freinage" (i.e., Working Party on Brakes and Running Gear)

Grub screw:

A fully threaded, headless screw.
Also See:
setscrew

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