DICTIONARY OF AUTOMOTIVE TERMS - "Tr"

TR
  1. Acronym for Thermal reactor
  2. Acronym for Transmission Range Sensor Commonly called PRNGL - this provides input of the Gear Selector position
TRA
Tire and Rim Association.
Tracer
See
Track
  1. Front track is the distance between the center of the left front wheel and the center of the right front wheel when the vehicle is set to its normal ride height and wheel alignment specifications. Rear track is the distance between the center of the left rear wheel and the center of the right rear wheel. They are not always the same.
  2. A designated course or roadway where vehicles race.
Also see
Track arc
The path traveled by a road wheel during a turn
Track bar
See
Track bike
A type of bicycle used for racing on a bicycle track (velodrome); looks a lot like a road bike but features only one gear and has no brakes.
Track control arm
See
Tracked
See
Tracker

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Tracker

A model of SUV produced by the Suzuki Motor Corporation and rebadged and sold through the Chevrolet division of General Motors from 1998 to 2004
Tracking
  1. The alignment of the vehicle with respect to axle centers of a vehicle being in the same plane, rear tires following front tires and trailer following the tractor, in the attitude designed. Correct tracking is when the rear wheels of a vehicle follow the same line as the front wheels.
  2. A line of carbon along which electricity leaks.
  3. Shunt firing of a spark plug.
Also see
Tracking mark
A telltale sign on the distributor cover or ignition cables indicating a leakage of current
Tracking Switch
See
Track rod
One of the transverse bars connecting the steering system to the steering arms; the link between the pitman arm and the steering-knuckle arm.
Also see
Tract
See
Traction
  1. Pulling force.
  2. The force of adhesive Friction exerted by a body on the surface on which it moves.
  3. Tires ability to grip the road. Higher traction allows greater braking and cornering force without slip, skid, or sinking.
Also see
Traction avant
A French term for Front-wheel drive
Traction bar
An Articulated bar or link attached to both FrameRear axle housing to prevent Spring windup (with resultant wheel hop) during heavy Acceleration or braking.
Also see
Traction control
  1. A system that helps prevent front-wheel spin on slippery or gravel surfaces during Acceleration at speeds up to 40 kph (25 mph).
  2. A means of preventing wheelspin due to acceleration, either by braking the spinning wheel or reducing engine power.
Also see
Traction controls
The lever controlling the transfer gearbox and center differential lock.
Traction control system
See
Traction differential
See
Traction engine
A steam or Diesel engine used for hauling heavy vehicles on roads or over difficult terrain.
Traction limited grade
Steepest negotiable grade where traction is the limiting factor.
Tractive conversion
See
Tractive effort
The amount of pull exerted by a vehicle as a result of traction.
Tractor
The truck portion of semi-tractor-trailer unit or train which is designed to pull a semitrailer by means of a fifth wheel mounted over the rear axle(s). It has no cargo capacity. Unlike a straight truck which has a cargo body mounted to the truck frame, the tractor has a circular fifth wheel plate for coupling to a semitrailer. A tractor may includes gooseneck hitch tractors, even though they lack fifth wheels; and includes auto carrier tractors with racks for carrying automobiles; includes mobile home haulers. Tractors can carry motor vehicles in a saddlemount or piggyback fashion. Sometimes called a truck tractor or highway tractor to differentiate from it from a Farm tractor.
Also see
Tractor-trailer
A Tractor and Semi-trailer combination.
Trade
See
Trade agreement
See
Trade Agreement of the Americas
See
Trade-in price
The price of your old car when you are selling it in part exchange for another one
Trade Organization
See
Traffic
A road with moving vehicles.
Also see
Trafficator
See
Traffic circle
An intersection of several roads where the traffic goes around a central circle and goes out another road. Although it is a rapid way of negotiating an intersection, many people are intimidated by it because of its unfamiliarity. The British term is roundabout
Traffic control devices
Signs, signals, markings, and other devices placed on or adjacent to a road to regulate, warn or guide traffic.
Traffic control measures
Elements of the traffic control plan including, but not limited to, traffic control devices, personnel, materials and equipment used to control traffic through a work zone.
Traffic control plan
A written and drawn plan for handling traffic on a specific roadway through a work zone.
Traffic Counters
See
Traffic island
A raised area in the middle of a road designed to separate two flows of traffic and to provide a safe temporary stopping place for pedestrians crossing the road
Traffic jam
A number of vehicles stopped behind one another on a road
Traffic lane
That part of the road marked for moving a single line of vehicles.
Traffic light
A series of red, amber, and green lights placed at the intersection to regulate the flow of traffic
Traffic Safety Administration
See
Trail
  1. A path used by pedestrians and smaller vehicles (e.g., bicycles, quads, snowmobiles, etc.).
  2. The path that a wheel makes.
Also see
Trail bike
A dual purpose motorcycle for use on or off-road
TrailBlazer
Trailblazer

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Trailblazer

A model of full-size SUV-van produced by the Chevrolet division of General Motors from 2002 to 2008
Trail braking
A driving technique in which the driver begins to brake before entering a turn and then continues to brake as he eases into the corner. As cornering forces build, the driver gradually feathers off the brakes -- trading braking power for cornering grip. By increasing the vertical loading -- and thus the Traction -- at the front tires, trail-braking can improve a car's turn-in.
Trail distance
The distance from the point at which the Cornering force acts to the center of the wheel or Steering axis.
Trailer
  1. Platform or container on wheels pulled by a truck or tractor.
  2. Distance between fifth wheel pin and center of rear axle (or center between tandems).
  3. A unit which contains camping equipment and is pulled behind a vehicle.
Also see
Trailer Kingpin
An anchor pin at the center of a semitrailer's upper coupler which is captured by the locking jaws of a tractor's fifth wheel to attach the tractor to the semitrailer.
Trailer On Flatcar
(TOFC) A method for moving cargo which involves transporting semitrailers on railroad flatcars.
Also see
Trailer preponderance
A condition where there is a heavier load on the front of the trailer (thus on the vehicle towing hitch) than on the back of the trailer.
Trailer tire
A small tire often 12" with a load range B and a capacity rating of 850 lbs
Trailer towing package
See
Trailer-towing package
An Optional equipment which usually includes a heavy-duty Suspension a larger Radiator a TransmissionCooler and a rear Bumper with a trailer hitch. This improves handling and allows a vehicle to haul a heavy trailer.
Trailer weight
See
Trailing
See
Trailing arm
Trailing arm

Trailing arm

Type of Independent rear suspension in which the pivot axis is exactly across the vehicle, or perpendicular to the longitudinal axis. This means the wheels are always upright relative to the body and hence leaning with the body in a corner. Widely used at the rear of front-wheel-drive cars.
Also see

Trailing axle
See
Trailing brake shoe
The Brake shoe that is installed facing the rear of the vehicle. Also called Secondary brake shoe or Reverse brake shoe.
Trailing edge
The rear edge (e.g., of a body panel). Compare Leading edge
Trailing link
A front Suspension linkage that is aligned to resist longitudinal motions in a wheel; it is mounted to the chassis ahead of the wheel. The links pivot forward of the axle.
Also see
Trailing link suspension
See
Trailing shoe
  1. A shoe whose friction surface trails behind the shoe pivot and is pushed away from the drum by drum rotation.
  2. A British term for a Secondary shoe -- a shoe of a brake drum system whose activated end faces away from the approaching drum
Trailing throttle
An oversteer handling situation of rear drive cars. When the throttle is closed the engine applies compression braking so that the rear suspension alignment changes. This change causes the rear tires to lose traction which promotes a lateral slide.
Train
See
Trainer
See
Train station
Trucker slang for Traffic court that fines everyone as in "Get out your money traffic court is a real train station today."
Train Stop
See
Train weight
See
Tram
  1. A British term for a Streetcar.
  2. A small train used to haul ore at a smelter.
Tramcar
A British term for a Streetcar
Tram gauge
An alignment tool -- a long bar that has two or three parallel pointers extending at right angles and attached so that they can be moved to any position along its length
Tramline
The rails along which a tram runs
Tramlining
The tendency of a vehicle's tires (often when of low profile) to follow a ridge or rut in the road's surface
Tramp
  1. A hopping or oscillating motion of the front wheels usually caused by incorrect balance or when a high inflation tire has been run empty.
  2. The action of rapidly depressing the throttle pedal.
Also see
Tramway
The rails along which a tram runs
Tranny
Colloquial name for Transmission.
Trans
Abbreviation for Transmission.
Trans Am
Trans Am

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Trans Am

A sports car manufactured by the Pontiac division of General Motors
Transaxle
A drive setup in which the Transmission Gearbox, Clutch, final drive, and Differential are combined into a single unit connected directly to the Driveshaft. It is used mostly in rear-engine cars like the Corvair or Front-wheel drive cars and some performance cars where a front engine/rear transaxle gives better overall balance (such as the Alfa Romeo Alfetta).
Also see
Transceiver
A radio device which can transmit a signal and opposite to a receiver
Transducer
  1. A device for transferring power which is generated in one system to another system in the same or a different form, e.g., electrical to mechanical.
  2. Any device that converts an input signal into an output signal. Used to actuate electric or vacuum servo motors in an automatic temperature control system.
  3. Device turned on by change of power from one source for purpose of supplying power in another form to second system.
Also see
Transducer Assembly
See
Transducer EGR
See
Transducer EGR valve
See
Transducer Valve
See
Transesterification
A process in which organically-derived oils or fats are combined with alcohol (ethanol or Methanol) in the presence of a Catalyst to form esters (ethyl or methyl ester).
Transfer
See
Transfer box
A device that transfers power from the main gearbox (transmission) to both the front axle and the rear axle on a four-wheel drive vehicle.
See
Transfer case
An auxiliary device in a 4-wheel-drive vehicle that allows power to be delivered to both axles. Normally the transfer case incorporates a shifting device so that the front drive can be disconnected, if desired, for running on pavement. It is mounted between the transmission and driveshaft.
Also see
Transfer Dump
A straight dump truck pulling a full dump trailer without hydraulics. The dump box of the trailer slides (transfers) into the empty dump bed of the power unit using the hydraulics of the power unit to unload.
Transfer Effect
See
Transference
See
Transfer Gear Lever
The small gear lever in the cab next to the main gear lever. It controls whether the transmission is in high ratio or low ratio in the transfer box. The same lever also controls the engagement of the differential lock.
Transfer Module
See
Transfer molding
The development of Compression molding where powder polymer is placed in a small chamber adjacent to a tool mold and when heated, is forced into the tool cavity.
Also see
Transfer moulding
British term for Transfer molding
Transfer passage
The passage connecting the crankcase of a two-stroke engine with the combustion chamber
Transfer plate
An adapter plate in the control valve assembly of an automatic transmission, used to direct the fluid flow between adjacent valve bodies
Transfer port
A Channel in the block of a Two-stroke engine where the Air-fuel mixture enters the Combustion chamber and exits out another transfer port after it burns.
Also see
Transfer port cover
The transfer passages of most two-stroke engines are accessible from the outside to allow for maintenance, they are covered by the transfer port covers for regular engine operation
Transfer ports
The holes that deliver fuel from the idle circuit during the transition from curb-idle to the main metering circuit. Located just above the throttle plates. At curb idle, off-idle ports function as an extra air bleed for further emulsification of the idle mixture; but as vacuum moves up the carburetor bore when the throttle plates are opened, they become fuel discharge ports. Either one or more holes, or a single slot (slots are usually used because they are cheaper to manufacture). Also called Off-idle discharge ports
Transfer pump
  1. An in-tank pump, used on many Bosch and some other fuel injection system, that boosts the fuel pressure slightly before the fuel is sucked into the main pump, in order to prevent cavitation. Also, part of the fuel injection pump for a diesel engine, boosts fuel pressure from around 20 psi to about 130 psi, depending on the pump and the engine speed
  2. Fuel pump located in the fuel tank, usually used with a two pump system
Transfer Slot
See
Transformer
  1. An electrical device with an arrangement of copper Coils with an iron center, used to increase or decrease electrical Voltage. A vehicle Ignition coil transforms the voltage from 12 volts to upward of 20,000 volts.
  2. Electromagnetic device which transfers electrical energy from primary circuit into variations of voltage in secondary circuit.
Also see
Transformer-rectifier
Combination transformer and rectifier in which input ac current may be varied and then rectified into DC current.
Transient
See
Transistor
  1. Electronic device commonly used for amplification. Similar in use to electron tube. Depends on conducting properties of semiconductors in which electrons moving in one direction are considered as leaving holes that serve as carriers of positive electricity in opposite direction.
  2. A small semi-conductor electronic component, with at least three connections but no moving parts, that functions as a switch, amplifier, or detector by controlling the flow of current.
See
Transistor ignition
A form of Ignition system which uses transistors and a special Coil. The conventional Distributor and point setup is used, but the points merely serve to trigger a transistor which switches the heavy primary Current. With the transistor unit, the Voltage remains constant, thus permitting high engine rpm without resultant engine miss. Transistors are much more efficient switches at high engine speeds and in addition they don't burn, pit or change gap spacing. The advantages of these systems include greatly increased point life, generally better starting because of improved contact condition and voltage output not greatly affected by Breaker pointDwell time which results in better high-rpm performance. Also point life is greatly extended as the transistor system passes a very small amount of Current through the points.
Transistorized coil ignition
(TCI)
Also see
Transistorized coil ignition with Hall sensor
(TCI-H)
Also see
Transistorized ignition
(TI) An ignition system using a transistor as a power switch; available as breaker-triggered TI with contact breaker or as breakerless TI with magnetic pick-up or hall generator.
Also see
Transistorized ignition with inductive pulse generator
See
Transistorized ignition with Hall generator
(TI-H) There are two types of TI-H in one version, the dwell angle is determined by the width of the rotor vanes in the distributor; the other version contains a circuit for automatic dwell angle control incorporated in the electronic control unit
Transistorized ignition with inductive pick-up
(TI-I) A transistorized ignition system with a magnetic pick-up in the distributor and an electronic control unit for signal processing, with current and dwell angle control
Transistorized ignition with magnetic pick-up
(TI-I) A transistorized ignition system with a magnetic pick-up in the distributor and an electronic control unit for signal processing, with current and dwell angle control
Transit
See
Transit Bus
A bus providing passenger transportation over fixed scheduled routes within primarily urban geographical areas.
Transition
See
Transitional Low-Emission Vehicle
(TLEV) A vehicle meeting either EPA's CFV TLEV standards or CARB's TLEV standards. TLEVs produce fewer emissions than federal Tier 1 vehicles. TLEVs are eligible for the federal California Pilot Program but not eligible for the Clean-Fuel Fleet Program. The TLEV standards are less stringent than the LEV standards.
Transit system
See
Transmission
  1. A component of gear that allow your car to move forward and backward with varying amounts of power to meet a variety of driving situations. Manual transmissions are operated by means of a clutch and gearshift. Automatic transmissions are driven by hydraulic pressure.
  2. A device (full of gears) that uses Gearing or Torque conversion to effect a change in the ratio between engine rpm and driving wheel rpm. When engine rpm goes up in relation to wheel rpm, more Torque but less speed is produced. A reduction in engine rpm in relation to wheel rpm produces a higher road speed but delivers less torque to the driving wheels.
  3. Heat loss or gain from a building through exterior components such as windows, walls, floors, etc.
Also see
Transmission adapter
A unit that allows a different make or year Transmission to be bolted up to the original engine.
Transmission, automatic
See
Transmission brake
The handbrake on all Land Rovers operates by gripping the rear propeller shaft at the point where it leaves the transfer gearbox and is thus called a transmission brake. It should be used as a parking brake only and should never be operated whilst the vehicle is in motion except in emergency -
Transmission control
See
Transmission controlled spark
(TCS) A system to reduce the emission of nitrous oxides by which a vacuum solenoid and a switch in the transmission system prevents the distributor's vacuum advance mechanism from operating in the lower gears and at low speed
Transmission control module
(TCM) An electronic automatic transmission control unit which computes data on the actual operating conditions of the vehicle and generates corresponding signal pulses for the solenoid valves of the hydraulic control system; may also exchange data with other electronic control units
Transmission control system
A hydraulic or electro-hydraulic system which controls the changes of ratio in automatic transmissions corresponding to engine load, vehicle speed, positions of the selector lever, and shift mode button
Transmission, conventional
See
Transmission cover
A removable part of the floorpan usually located at the front end of the center tunnel in cars with a longitudinally mounted engine; provides better access to the top of the transmission for maintenance and adjustment purposes
Transmission extension housing
A rear-wheel drive transmission housing enclosing an extended main shaft, sometimes accommodating the gear lever and associated mechanism
Transmission fluid
(ATF) A superthin oil that fills the Automatic transmission system so that it can run on Hydraulic pressure. It can also be used in some power-steering pumps. It is sometimes used to clean the inside of a Carburetor.
Also see
Transmission governor
A governor on the output shaft of a hydraulically controlled transmission converts line pressure into governor pressure. In electro-hydraulically controlled transmissions, the governor is replaced by a sensor.
Transmission housing
The outer shell which contains the Transmission gears.
Transmission input shaft
A spinning shaft which transmits power from the clutch to the gearbox
Transmission output shaft
A spinning shaft which transmits the power out of the transmission
Transmission powertrain control module
An electronic module or a computer that receives input from various transmission related sensors to determine the operating condition of the transmission at a particular moment. The transmission module or computer responds to these signals and/or input from the PCME by sending signals to various transmission controls to meet predetermined operating instructions.
Transmission shifter
See
Transmission tunnel
A semicircular or oval bulge along the longitudinal axis of the floorpan to accommodate the propeller shaft and, at its front end, the transmission, enabling the shaft and transmission mounting position to be raised to the floorpan level, thus providing better protection for the drive train against road dirt and obstacles
Transmission wind-up
A 4x4 with no center differential or one driven with the center differential locked (i.e., in both cases the front and rear propeller shafts locked together) is unable to accommodate the small differences in distance normally traveled by the front wheels compared to the rear wheels. The differential lock ensures both propeller shafts rotate exactly the same amount despite the small differences in distance actually traveled. This results in some wheel slip and skid which, on loose ground, can take place without any harm. On hard roads, however, the superior wheel grip makes it difficult for the wheels to slip much and in the process of trying to do so considerable torsional stress builds up in the transmission. This is known as transmission wind-up and can sometimes exert so much stress that the differential lock gears will not disengage when so selected. You will also sense very heavy steering. If this occurs due to your forgetting to de-select differential lock on hard ground (or at any other time) and the differential lock will not disengage, the solution is to reverse the vehicle some distance until the differential lock warning light goes out.
Transmitter
A radio remote control system device that transmits electrical or radio signals.
Also see
Transmitting Valve
See
Transom
A horizontal bar or beam
Transom beam
The aftermost transverse deck beam
Transom frame
The aftermost transverse side frame
Transom stern
A square-ended stern used to provide additional hull volume and deck space aft and to decrease resistance in some high speed ships.
Transplants
An overseas production plant; in most cases, the term refers to automotive vehicles produced in the USA, Canada, or Europe at Japanese-owned factories (e.g., a Toyota plant in Cambridge, Ontario, Canada)
Transport
See
Transportation
A means of carrying goods or people by light duty vehicles, busses, heavy-duty vehicles, and off-road vehicles.
Also see
Transportation Research Board
(TRB) Serves as an independent adviser to the U.S. federal government and others on scientific and technical questions of national importance. Promotes innovation and progress in transportation through research; stimulates research and offers research management services that promote technical excellence; provides advice on policy and programs.
Transportation Safety Board
See
Transportation sector
An energy-consuming sector that consists of all vehicles whose primary purpose is transporting people and/or goods from one physical location to another. Included are automobiles; trucks; buses; motorcycles; trains, subways, and other rail vehicles; aircraft; and ships, barges, and other waterborne vehicles. Vehicles whose primary purpose is not transportation (e.g., construction cranes and bulldozers, farming vehicles, and warehouse tractors and forklifts) are classified in the sector of their primary use. Note: Various EIA programs differ in sectoral coverage. Click here for an explanation of the variations of the transportation sector used by EIA system(s).
Transportation Systems
See
Transporter
A large articulated truck for transporting several cars (on two or three decks)
Transverse arm
A Suspension arm not split into two separate sections as is an A-arm. Often used as the bottom locating link with MacPherson strut suspension. Also called lateral arm.
Also see
Transverse cable
See
Transverse engine
An engine that is mounted laterally (i.e., left to right) between the drive wheels (rather than longitudinally -- front to back), often found on cars with Front-wheel drive. Also called east-west layout
Transverse flow scavenging
See
Transverse leaf spring
A Leaf spring that is mounted so that it is at right angles to the length of the vehicle.
Transverse link
Any suspension link that provides lateral support for wheels; on front suspensions, a typical design is the Y-shaped wishbone
Transverse mount
The engine is mounted sideways. The fan belt will be over one of the tires rather than in the very front of the vehicle. This is common in front-wheel-drive cars. This enables the car to be more compact because the space under the hood is used more efficiently and provides better weight distribution.
Also see
Transverse rod
See
Transverse torsion bar
See
Trap
  1. The area over which the vehicle is raced for timing purposes.
  2. A filter or separator
  3. A pedal on a Bicycle into which the foot is locked in place.
Also see
Trap oxidizer
In diesel particulate filters, a means of burning the particulate charge trapped in the filter element, to prevent the filter from clogging and to restore filtration capacity; usually a catalyst coating that promotes oxidation of carbon particulates to harmless carbon dioxide
Trapped volume
A Clearance volume
Trapping efficiency
In a two-stroke engine, the mass of fresh charge in a cylinder actually retained, divided by the mass of fresh charge supplied per cycle
Trauma fee
$6 per $1000 of car value levied annually in Washington State (and others) to support trauma units in hospitals that care predominantly for car crash victims.
Travel
  1. The distance an object can move.
  2. The distance that suspension components, forks and shocks, move up and down when the bike rides over bumps.
  3. Measurement of the total distance that a shock can move.
Also see
Travel trailer
Travel Trailer

Travel Trailer

A recreational unit which is pulled behind a vehicle and has similar amenities that are featured on a Class A RV. Some have slideout sections to extend the living space. They can sleep up to eight people. They feature a small bedroom, bathroom (toilet, shower), fully equipped galley (cooking facilities, refrigerator, sink, faucets), water tanks (fresh water, grey water, black water), heater, air conditioner, a LP (propane) gas supply, and a separate 100-125 volt electrical system Most tow vehicles must be equipped with a load distributing hitch and other special devices designed to control the sway of the trailer.
travel trailer

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travel trailer

  • Average weight under 4000 pounds
  • Average length 10 ft to 35 ft
  • Average price $10,000 to $100,000
Also see

Traveled
See
Tray
See
Tray table
A table that folds out of the back of the front seat (similar to those found on airplanes)
TRB
Acronym for Transportation Research Board which serves as an independent adviser to the U.S. federal government and others on scientific and technical questions of national importance. Promotes innovation and progress in transportation through research; stimulates research and offers research management services that promote technical excellence; provides advice on policy and programs.
TR-Denioc rim
See
TR-Denioc wheel
See
Tread
  1. The distance between the two front or two rear wheels.
  2. Portion of the tire which contacts the roadway.
  3. The grooves on a tire which provide a grip on the road
  4. The pattern of the outside circumference surface of a tire.
  5. Load-bearing surface of a trail or road.
Also see
Tread bar
Raised portions of rubber that make up me tread of the tire, separated by grooves that are arranged laterally, providing traction in the forward or rearward direction.
Tread block
Raised portions of rubber that make up part of the tread pattern They are often present in the shoulder area and are more or less rectangular in shape.
Tread depth
The measurement from the bottom cm of the tread groove to the top of the tread expressed in millimeters or 32nds of an inch. The legal minimum amount of tread is 1.6 mm (2/32") across three-quarters of the tire width
Tread depth gauge
A simple compact device for measuring the depth of tread, consisting of a spring-loaded plunger calibrated in millimeters or 1/32 of an inch
Tread gauge
See
Tread groove
One of several channels cut in the tread that disperses road water or provides traction in mud and snow
Tread pattern
Tread patterns differ according to the manufacturer of the tire but they all have in common the aim of dispersing water from the road, to enhance grip, to avoid aquaplaning, to disperse heat, and to reduce noise and wear
Tread pattern percentage
(TPP) The percentage of grooves and sipes to the overall surface of the tread
Tread profile
The shape of the tread as seen in cross section
Tread rib
The continuous raised portions of rubber that run circumferentially (straight or in a zigzag pattern) making up the tread on the tire. Also called the Tread bar
Tread roller
A roller, either manual or power, used to help apply me tread rubber, remove trapped air and obtain adhesion.
Also see
Tread rubber
See
Tread separation
Pulling away of the tread from the Tire casing.
Tread squirm
The flexibility in the Tire tread between the surface of the Tread and the tire carcass. Snow tires, with their small, deep, unsupported tread blocks, have a large amount of tread squirm. Slick racing tires, which have no tread pattern, have very little squirm.
Tread wear indicator
See
Tread-wear indicator
See
Tread wear indicators
See
Tread-wear indicators
Bars of hard rubber that appear across the treads of a tire. They are 1.5 mm (1/16") above the base of the tread (the legal limit. They become visible when the Tread has been worn down so that only 1.5 mm (a sixteenth of an inch) of tread is left. The legal limit may be shown on the sidewall by a symbol or by the letters TWI
Treatment
See
Tree
See
Triac
Three-lead semiconductor that allows current flow in two directions when a preset voltage is applied at one of the leads.
Trial
See
Trials
A type of ATB bicycle or off-road motorcycle competition that tests riders not on speed but on ability to maintain balance while navigating around and over numerous obstacles such as rocks, trees, and steep, slippery terrain. Points are deducted if the rider puts his feet on the ground, goes outside the marked course, or fails to clear an obstacle.
Also see
Triangle
See
Triangle split system
Dual brakes

Dual brakes

A Brake system that uses a tandem or dual Master cylinder to provide separate Brake system for both front and rear of vehicle. In the event of a loss of Hydraulic fluid, one system may still work because it is independent of the other system. Some cars like the Rolls-Royce, link the two front brakes with the right rear brake, and the two front brakes with the left rear brake.
Also see

Triangle-split system
See
Triangular ground electrode
A ground electrode with three bridges attached to its end points, which form a link to the threaded shell
Triangular safety reflector
See
Triangulation
The arrangement of the stabilizing tread plies whereby their cords form tiny triangles in the Michelin 'X. radial truck tire.
Triathlon
A competition in which the participant must swim, cycle, and run a designated distance in each discipline.
Triathlon tire
Triathlon bicycle tires are usually 650c. Although they are sometimes referred to as 26 inch, they are not compatible with tires meant to fit ATB rims.
Triathlon wheel
A wheel consists of a hub, rim, and spokes. Triathletes often prefer to use smaller size wheels than road riders. Triathlon specific wheels are size 650C.
Tri-Axle
  1. A truck, tractor, or trailer with three axles grouped together at the rear.
  2. Normally implies four total axles if used to refer to a straight truck.
Also see
Tri bars
See
Tricar
An old name for a three-wheeler
Tricarbonyl
See
Trichlorethene
(C2HCl3) A cleaning solvent Methyl chloroform
Trichlorethylene
(C2HCl3) A cleaning solvent
Trichlorotrifluoroethane
Complete name of refrigerant R-1 13. Group 1 refrigerant in rather common use. Chemical compounds which make up this refrigerant are chlorine, fluorine, and ethane.
Trick
  1. A description of a whole motorcycle which is really cool, really hot, really new and unobtainable or expensive.
  2. A component of a motorcycle which is unique
Trickle charge
A continuous charging of a storage battery at a low rate to keep it in a fully charged condition for a period when no current is drawn from it
Trickle charger
A small battery charger which delivers less than five amperes
Tricycle
A three wheeled vehicle (usually pedal-powered) where there is a single front wheel and two rear wheels. A three-wheeled, early-type open automobile using bicycle wheels and a steel-tube frame.
Also see
Tridem
A group of three axles on a truck, tractor, or trailer. Tridems are most common on European semi-trailers.
Tri-drive
A vehicle having three rear driving axles.
Trier
An implement used in testing something such as the variation from level (e.g., Bubble Trier)
Triflex
A stretchable laminate of Polartec Fleece and Nylon/Lycra. Windproof, waterproof and breathable. Triflex creates the warmest cold weather cycling gear.
Trigger box
See
Triggering device
An electronic control unit that activates the air bag in a crash. It contains a deceleration sensor, a Hamlin switch and a check circuit
Triggering mechanism
A device that controls the timing of the ignition module or ignition coils on vehicles with electronic ignition systems.
Triggering unit
An electronic control unit that activates the air bag in a crash. It contains a deceleration sensor, a Hamlin switch and a check circuit
Trigger wheel
  1. A rotor of a magnetic pick-up integrated into the distributor, with as many teeth as the engine has cylinders.
  2. A Hall generator rotor with an outer ring interrupted by one or several Hall windows, depending on its purpose
  3. A Reluctor
Trike
A Tricycle. A motorcycle that has been converted to a three-wheeled unit. Sometimes the rear two wheels are powered by a small automobile engine.
Trim
  1. Nonfunctional metal or plastic molding, Frames and other decorative additions to vehicle bodies and interiors. Also called Hard trim.
  2. A vehicle's interior decoration, including the upholstery, roof and door linings. Also called Soft trim.
  3. The difference between the draft forward and the draft aft. A ship is trimmed by adjusting the location of fuel, cargo, ballast, etc.
Also see
Trimaran
A triple hulled vessel
Trim emblem
See
Trim Heads
Similar to the 82 degree flat and oval head machine screws except that the size of head for a given size screw is one or two sizes smaller than the regular flat and oval sizes.
Trim level
A vehicle designation assigned by vehicle manufacturers that represent specific equipment packages.
Trim Pad
See
Trim panel
The decorative interior panel
Trim panel release tool
A fork-like tool used to pry out fasteners on interior panels without breaking them or damaging the car
Trim rim
See
Tri-oval track
An oval track with an extra rounded corner. Daytona is a tri-oval track.
Trip
  1. In the OBD system, a journey during which all OBD tests have been completed.
  2. Acronym for The Road Information Project -- a nonprofit organization that promotes transportation policies that relieve traffic congestion, improve air quality, make highway travel safer and enhance economic productivity.
Also see
Trip computer
A computer with a multifunction display; supplies the driver with trip information such as range, ETA, distance to destination, time, fuel economy, fuel consumption, average speed, accumulated trip miles, elapsed time since last reset
Tri pin
Tri pin

Tri pin

A device which is attached to a steering wheel to allow disabled people to insert a hand into its bracket in order to steer a vehicle.
Triple
See
Trip Leasing
Leasing a company's vehicle to another transportation provider for a single trip.
Triple clamp
The devices which secure the Handlebar to the Triple tree on a motorcycle. Named because is has three clamping points -- one for each of the two front forks, and one for the steering tube.
Triple crank
A crankset with three chainrings designed to provide a wide range of gears and gear intervals
Triple point
Pressure-temperature condition in which a substance is in equilibrium (balance) in solid, liquid, and vapor states.
Triple tree
The Yoke that supports the Handlebar on a motorcycle.
Triplex chain
A chain with three rows of rollers.
Also see
Trip meter
An instrument which measures the distance a vehicle travels from the last time it was reset and runs in conjunction with the odometer
Trip mileage counter
An instrument which measures the distance a vehicle travels from the last time it was reset and runs in conjunction with the odometer
Tripod jack
A device for lifting a vehicle.
Tripod joint
A constant velocity joint with three balls engaged in curved grooves
Trip odometer
An auxiliary Odometer that may be reset to zero at the option of the Driver. It is used for keeping track of the mileage on trips up to one thousand miles.
Tripolyphosphate
See
Tripping bracket
Flat bars or plates fitted at various points on deck girders, stiffeners, or beams as reinforcements to prevent their free flanges from tripping
Trip recorder
  1. Incorporated in the speedometer, the trip recorder indicates the distance (in miles or km) covered during a particular journey (trip), either mechanically or electronically; trip figures can be reset to zero by turning or pushing a reset button. Also called a Trip meter, Trip mileage counter, or Trip odometer
  2. A cab-mounted device which electronically or mechanically records data such as truck speed, engine rpm, idle time and other information useful to trucking management.
Also see
Triumph
Triumph

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Triumph

A vehicle brand of motorcycles and automobiles of which the following car models are classic cars:
  • Dolomite 8
  • Gloria 6
The 1953-63 TR2/TR3 models are milestone cars.
Trk
See
TRLHP
Acronym for Thermal Vacuum Valve
TR number
Code number of the tube valves and flaps set by Tire and Rim Association.
Trolley
See
Trolleybus
Trolley bus

Trolley bus

An electrically powered public transport bus that takes its power from overhead wires
Trolley jack
A hydraulic jack with swivel wheels
Trolley Reverser
See
Troposphere
Part of the atmosphere immediately above the earth's surface in which most weather disturbances occur.
Tropospheric ozone
(smog) is formed when volatile organic compounds (VOCs), oxygen and NOx react in the presence of sunlight (not to be confused with stratospheric ozone, which is found in the upper atmosphere and protects the earth from the sun's ultraviolet rays). Though beneficial in the upper atmosphere, at ground level, ozone is a respiratory irritant and considered a pollutant.
Trouble code
  1. Engine self diagnosis. Electronic control module questions sensor reading and stores code for which circuit trouble is located
  2. Numerical codes created y an electronic module with self-diagnostic capabilities and normally stored in the module memory. They result from a system self-test that indicates a circuit or subsystem problem, or a general condition that is not within limits. Often called fault or service codes, they are now referred to as diagnostic trouble codes.
Also see
Troubleshooting
Diagnosing engine, Transmission etc., problems by various tests and observations.
Trouble-shooting light
A light with a long lead, used in garages to inspect the underside of cars and under the hood
Trough
High-temperature (180+) concentrator with one axis-tracking.
Also see
Troy weight
A system of measurement of weight used for gold, silver, and platinum
Troy ounce
A measurement of weight where one troy ounce equals 31.10 grams. In writing, it is often shortened to troy oz. after figures, e.g., 25.2 troy oz. Troy weight is divided into grains, pennyweights (24 grains = 1 pennyweight), ounces (20 pennyweights = 1 ounce) and pounds (12 troy ounces = 1 pound). Troy weights are slightly less than their avoirdupois equivalents; the troy pound equals 0.37 kg or 0.82 lb avoirdupois
TR rim
A safety rim developed by Michelin with a flattened rim flange and run-flat potential
TRS
Acronym for Transmission Regulated Spark Control System
TRS+1
Acronym for Transmission Regulated Spark Control System
TRUARC® retaining ring
A trade name for an internal or external circlip of rectangular cross section with holes for easier installation and removal. www.truarc.com
Truck
  1. A general term for a vehicle designed to haul something. The British term is lorry.
  2. Vehicle which carries cargo in a body mounted to its chassis, rather than on a trailer towed by the vehicle.
Also see
Truck camper
Truck camper

Truck camper

A vacation unit which mounts on the bed of a pickup truck. Also called pickup camper, or slide-on camper, slide-in camper, or simply camper. Usually the tailgate of the pickup is removed and the camper unit is clamped to the truck. It provides as much as cooking facilities, a refrigerator, heater, air conditioner, a self-contained toilet, a fresh water tank, a waste water tank, a faucet, a sink, a LP (propane) gas supply, and a separate 100-125 volt electrical system. They can sleep from two to six people. Prices range from $5,000 to $30,000. Its advantage is that the vehicle can be used to drive into remote locations.
Truck classification
Vehicle classifications for automobiles and light duty trucks were obtained from the EPA mileage guide book. Almost every year there are small changes in the classifications, therefore the categories will change accordingly. The EPA mileage guide can be found at any new car dealership.
Trucker
A person who drives a large truck (i.e., larger than a pickup) -- usually one who drives a semi-tractor
See
Trucker slang
A colloquial set of expressions used on a CB communication device.
Truck Ramp
See
Truck Tractor
The truck portion of semi-tractor-trailer unit or train which is designed to pull a semitrailer by means of a fifth wheel mounted over the rear axle(s). Also called a highway tractor
Truck-type switchgear
A switchgear mounted on a platform with wheels
True
  1. Something that is accurately made or correctly adjusted.
  2. To adjust something so that it is able to fit perfectly.
Also see
True and Level Paving
(T&L) The roadway is paved with asphalt concrete to raise up the low spots and re-establish a proper "crown" for the road. This promotes good drainage of water off the road and improves the smoothness of ride quality. The final treatment may actually skim over some areas that will show little to no new asphalt, while other areas receive a couple inches of new asphalt. This work may take several days, and is usually followed by the application of a surface treatment.
True Paving
See
True up
To Dress
Truing
The act of cutting rubber off the tread of a tire while rotating on a truing machine to make the tire assembly round. A sometimes harmful practice which takes off tread rubber to allow for an out of round wheel, or for a tire not mounted properly.
Truncation of Thread
See
Trunion
A British term for Kingpin -- a mechanical pivot located at the lower end of the suspension wheel upright.
Trunk
The storage compartment of a vehicle. In older cars, a large suitcase (or trunk) was strapped to the back of the vehicle. In rear-engine vehicles, the trunk is located in the front of the vehicle (e.g., Volkswagen); but generally it is located at the rear of the vehicle.
Also see
Trunk handle
A lever or handle for opening the trunk
Trunk lid
The cover of the trunk which is hinged
Trunk model
A vehicle which may come as a hatchback or stationwagon is available in a style which has a trunk behind and below the backlight (i.e., rear window).
Trunk rack
  1. A luggage rack which is mounted to the surface of the trunk. Some are merely decorative.
  2. A bicycle carrying attachment mounted by straps to the rear of a car or truck. Less expensive than most roof or hitch racks.
Trunk spoiler
A Rear spoiler which is mounted to the lid of the trunk.
Truss
A supporting framework for a bridge
Truss Head
Low rounded top surface with a flat bearing surface.

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