- Roadbed
- In highway construction, the graded portion of a highway within top and side slopes, prepared as a foundation for the pavement structure and shoulder.
- Road closure
- An action by the authorities to stop vehicles from using a road. It is usually done when there has been a serious accident blocking the road or when the road conditions are bad (such as snow storms, earthquakes, avalanches, etc.).
- Road construction
-
Improvements made to the road surface. When passing construction sites, speed limits are greatly reduced. In many locations fines are doubled in construction zones
Road Construction sign
- Road Construction Signage
- Every road and bridge construction project must use signage to alert motorists of the construction ahead. Construction signage is usually orange with black lettering, sometimes with flashing yellow lights. Road construction requires motorists to slow down, so watch for alternate speed limits imposed on road and bridge construction projects. It is common to see signs that fines double in construction zones.
- Road-draft tube
- British term for Oil breather pipe or Oil breather tube.
- Road feel
- The impression imparted to the driver through the Steering wheel by the wheels of a vehicle in motion. This feeling can be very important in sensing and predetermining vehicle steering response.
- Road hazard
- Injury to a tire sustained in normal operation, excluding collision or vandalism and that is not reparable by accepted standards.
- Road holding
- The ability of a vehicle to grip the pavement. Technically described as Lateral acceleration, because cornering is actually a continuous deviation from a straight path. Measured in g's.
- Road load horsepower
- The amount of power at the driving wheels needed to move a vehicle down the road at a steady Speed. This power varies according to the vehicle's speed, aerodynamic drag, mechanical friction, and the tires' rolling Resistance. Road-load horsepower is distinct from engine power because the output of the engine is sapped by various mechanical losses between the engine's output at its flywheel and the driving wheels.
- Roadmaster
- A model of automobile manufactured by Buick Division of General Motors from 1936-1958, 1991-1996
- Road oil
- Any heavy petroleum oil, including residual asphaltic oil used as a dust pallative and surface treatment on roads and highways. It is generally produced in six grades, from 0, the most liquid, to 5, the most viscous.
- Road rage
- The violent behavior by a driver which may be precipitated by being cut off, forgetting to signal, getting an insulting gesture, or other forms of aggressive driving. A deliberate and violent act against another driver and is a criminal offense.
- RoadRailer®
- Semitrailer designed to travel both on highway and on rails. Manufactured by Wabash National Corporation.
- Road rash
- Any type of bruise or wound that is inflicted when you hit the ground, generally in a low-speed crash. A skinned knee is a type of road rash; multiply that by 100 and you get road rash that happens to unprotected motorcycle riders during an accident. High-speed crashes do much more damage.
- Roadside Assistance
- A service available from General Motors, during the warranty period, to assist you whenever a problem may occur (e.g. lock-out assistance, a jump start, flat tire change, fuel delivery or towing assistance).
- Roadside turnout
- A wide area to the side of the road to permit you to park your car so you can make repairs, change drivers, or empty garbage (when there is a large garbage can supplied).
- Roadster
- (Rdstr) This term derives from equestrian vocabulary where it was applied to a horse used
for riding on the roads. Old dictionaries define the roadster as an open-type car designed for use
on ordinary roads, with a single seat for two persons and, often, a rumble seat. It is an
open-type body with one bench seat and a luggage compartment in the rear deck. The
weatherproof fabric top may be folded, and side curtains may be removed. The Windshield usually may be folded down. The original
concept is maintained by the Morgan Plus 8 but modern roadsters include power features such as
power steering, electric windows, etc. as in the Mercedes-Benz SL.
Also see
- Road test
-
- A test to check that a car is roadworthy after repair.
- A test of a car (e.g., a new model) in actual use; for example, by a magazine for comparison with other models.
- An examination of a driver's ability and skill to operate a vehicle within the parameters of a licensing agency. Usually administered after the candidate has passed a written test proving his knowledge of the rules of the road
See also
- Road-test
- To give a vehicle a Road test.
- Road train
- Several linked trailers pulled by a large truck; common in Australia for transporting stock.
- Roadway
- That part of the road designed and used for vehicular travel. It does not include the median, berm, or shoulder.
- Road Weather Information Systems
- (RWIS) Provides real-time atmospheric weather data, pavement temperature and surface conditions. Links to weather forecasts, weather warnings, and radar and satellite images.
- Road wheel
- A bicycle wheel consists of a hub, rim, and spokes. Modern road wheels are generally size 700C. Older road bike wheels may be 27 in.
- Roamer
- A vehicle brand of which the following models are
classic cars:
- All Rochester-Duesenberg 4-cylinder
- 1925 6-54E
- 1925-1929 8-88
- 1929-1931 8-125
- Robertson screw
- A screw with a recessed square hole. It is more commonly found in Canada than the US, especially in woodworking situations. It is easier to install and remove than a Phillips screw and does not strip the head as easily. There are four basic sizes (measured across the flats) 1.6 mm, 2.0 mm, 2.6 mm, and 3.0 mm.
- Rochet-Schneider
- A vehicle brand of which the 1925-1948 models with required application are classic cars.
- Rocker arm
- A curved lever that pivots in the middle. One end is attached to the top of the Valve stem. In overhead-valve engines the other end is attached to the Pushrod. In some overhead-cam engines the other end is attached directly to the Camshaft lobe. As the camshaft rotates, the rocker arms pivot causing the valves to open and close.
- Rocker arm cover
- A metal lid located on top of the Cylinder head
on vehicles that have valves that are activated by an overhead cam or by
Rocker arms.
Also see
- Rocker arm shaft
- The shaft upon which the Rocker arms are mounted so that the rocker arms can pivot. Also called rocker shaft.
- Rocker box
- A British term for Valve cover (i.e., a cylinder head cover above the valve train).
- Rocker cover
- A British term for Valve cover (i.e., a cylinder head cover above the valve train).
- Rocker cover gasket
- A British term for Valve cover gasket, (i.e., a gasket between the cylinder head and the valve cover; usually either a flat paper or cork gasket or an O-ring.
- Rocker panel
- That section of the vehicle body between the front and rear Fenders and beneath the doors. A Sill.
- Rocker shaft
-
- The shaft on which the rocker arm pivots
- A British term for Cross shaft (i.e., the outgoing shaft of the steering gearbox, to which the pitman arm is connected).
- Rocking chair
- Trucker slang for vehicle between 2 trucks as in "Who we got in the rocking chair tonight."
- Rockwell Hardness Test
- A measure of hardness by determining the depth of penetration of a penetrator into the specimen under certain fixed conditions of test. The penetrator may be either a steel ball or a diamond sphero-conical penetrator. The hardness number is related to the depth of indentation and the higher the number the harder the material.
- Rocky Mountain Doubles
- A combination vehicle consisting of a tractor pulling a 45 to 48 foot semitrailer and second shorter semitrailer (usually 28 feet in length).
- Roc Loc
- An adjustable retention system extending off the back of Giro Helmets that allows the helmet to grip the users head better.
- Rod
-
- A modified car, i.e., Street rod.
- To drive a vehicle hard.
- A Connecting rod.
- To clean out a Radiator by passing a rod through the lines by Rodding the radiator.
- A thin bar.
Also see- Boxed rod
- Brake rod
- Connecting rod
- Filler rod
- Forked con rod
- Hood rod
- Hot rod
- Master con rod
- Metering rod
- Panhard rod
- Panhard rod mounting box
- Piston rod
- Push rod
- Pushrod engine
- Radius rod
- Relay rod
- Selector rod
- Slave con rod
- Steering rod
- Street rod
- Threaded rod
- Throwing a rod
- Tie rod
- Track rod
- TV rod
- Welding rod
- Rodding the radiator
- The top and sometimes, the bottom tank of the Radiator is removed. The Core is then cleaned by passing a cleaning rod down through the tubes. This is done when radiators are quite clogged with rust, Scale, and various mineral deposits.
- Roger beep
- Trucker slang for an add-on device for CB's that beeps when the mike key is pressed or released as in "How much did that roger beep cost ya?"
- Rohr
- A vehicle brand of which the 1925-1948 models are classic cars.
- Roll
- The motion of a vehicle in which the springs on one side of the vehicle compress while the springs on the other side extend. If the roll is extensive, the vehicle will fall on its side. Also less accurately called sway or lean, it occurs in corners because the car's center of gravity is almost always higher than the axis about which it rotates.
- Roll angle
- The angular displacement of a vehicle about its longitudinal axis, i.e., tendency of a vehicle to tip over when cornering or in high cross winds.
- Roll back
- To work a sales deal backwards. Instead of working with the purchase price and trying to determine a monthly payment, you would start with a known monthly payment and try to determine a selling price. It also means to roll back the odometer on a car to make it worth more money - highly illegal.
- Rollbar
- A heavy steel bar or tubular steel that goes from one side of the Frame, up and around in back of the Driver in a hoop, and back down to the
other side of the Frame. It is used to protect the Driver in the event his vehicle rolls over.
Also see
- Roll cage
-
A protective structure which surrounds the Driver in the event of a rollover or crash. It includes a Rollbar and other bars welded to the rollbar. The roll cage also adds Chassis strength and stiffness which makes for better handling characteristics.
Roll cage
Also see
- Roll center
- A term which is used to describe the point around which the body of the vehicle rolls when it corners. If the movement of the vehicle is controlled only by Linkages, the roll center can be discovered by the geometry of the Suspension.
- Rolled Point
- The point frequently produced by the cupping of the last 1 to 1 1/2 threads by the thread rolling pressure. This type of point is not produced intentionally but is considered as an alternative form of the plain sheared point.
- Rolled thread
- Rolled threads are cold formed by squeezing the blank between reciprocating or revolving serrated dies, similar to rolling a pencil between your two hands. This acts to increase the major diameter of the thread over and above the diameter of the unthreaded shank, if any. Rolled threads are both stronger and smoother than cut threads and more economical in so far as the process is faster with no waste of material. Virtually all cold headed fasteners within the Aerospace Industry today have rolled threads.
- Roller
-
- A device for replacing sliding Friction with rolling friction.
- While ball bearings use a series of balls in a cage, roller bearings use a series of small cylinders.
- A colloquial term for a Rolls-Royce.
- Roller bearing
-
An anti-friction bearing using a series of straight, cupped, or tapered steel Rollers engaging an inner and outer ring or Race.
Roller bearing
- Rollercam brakes
- Mountain bike brakes that are attached to the Frame posts and use a cam and Pulley system to modify pressure on the rims.
- Roller chain
- A power-transmitting chain in which each link consists of two free-moving rollers located by pins
connected to sideplates.
Also see
- Roller clutch
- A Clutch, using a series of Rollers placed in
ramps, that will provide drive power in one direction but will slip or
Freewheel in the other direction.
Also see
- Roller dynamometer
- A dynamometer attached to a number of rollers so that the vehicle's
driving wheels are
placed on them to simulate road conditions. In this way a vehicle's actual
power to the wheels can
be determined.
Also see
- Roller leveling
- A process in which steel strips pass rollers which remove excess zinc after the actual immersion process of galvanizing has begun.
- Rollers
- A stationary training device that consists of a boxlike Frame and three rotating cylinders (one for a bike's front wheel and two for its rear wheel) on which the Bicycle is balanced and ridden.
- Roller skate
- Trucker slang for a small car as in, "We got a roller skate broke down in the left lane so watch out."
- Roller tappets
- Valve lifters that have a Roller placed on the end contacting the Camshaft. This is done to reduce Friction between the lobe and lifter. They are generally used when special Camshafts and high tension Valve springs have been installed. Also called roller lifters or roller foot levers.
- Roller-vane pump
- A rotary vane pump with rollers as pumping elements which slide
against the pump body
when the rotor rotates.
Also see
- Rolling parking lot
- Trucker slang for an automobile transport as in "Who's that in the rolling parking lot southbound."
- Rolling radius
- The distance from the center of the tire's ground Contact patch to the center of the wheel rim. It is measured with tire loaded to rated capacity. Used in calculating geared speed.
- Rolling resistance
- As the wheels begin to turn, there are forces which resist its motion such as low tire pressure, rough road surface, increased tire temperature, tire composition, increased vehicle weight, and even air resistance.
- Rolling road
- Rollers set in the floor of a service center and designed to simulate road conditions; the rollers can be driven by the driving wheels of a car and connected to a dynamometer for testing the power output of an engine or may be independently powered, e.g., to test the brakes.
- Rolling start
- A form of race start that begins with the cars already in formation, while also in motion.
- Roll-Off Container
- Typically an open top container designed for transporting solids in bulk, often used as refuse container. The vehicles used for transporting roll-off containers have rails or a flat bed with a hydraulic hoist for loading and unloading these large containers.
- Roll oversteer
- Oversteer caused by roll when cornering. The opposite is Roll understeer.
- Roll pin
- A split, tube-like pin made of spring steel for retaining disc pads,
gears to shafts in
gearboxes, etc.
Also see
- Rolls
- Acronym for Rolls Royce.
Also see
- Rolls-Royce
-
A vehicle brand of which all models from 1919 to 1948 are classic cars. All the 1947-67 models are milestone cars.
Click image for books on
Rolls-Royce
- Roll steer
- A characteristic of handling which gives a slight improvement to steering as the Suspension moves in body roll. Sometimes a bad roll steer occurs when the Suspension is poorly designed. A steering effect induced by load transference from side to side. The axles may move out of their normal parallel relationship due to spring deflection.
- Roll stiffness
- The turning moment or Torque that the Suspension makes when the body rolls and the suspension tries to pull the body back to its normal upright position. It is usually measured in lb-ft/degree of roll. When the springs are stiffer or when the perpendicular distance from the springs to the Roll center is greater then the roll stiffness increases. As a result, the vehicle corners flatter. Also called roll resistance.
- Roll test
- An examination of the drive train functions; may include separate tests for front and rear axle, left-hand and right-hand sides, noise test.
- Roll threading
- Forming threads on a bolt or screw by pushing or rolling the piece through cutting dies.
There are two styles of cutting dies:
- one plate moves and the other is stationary
- rotating grooved circular rolls
- Roll understeer
- Understeer caused by roll when cornering. The opposite is Roll oversteer.
- ROM
- Acronym for Read Only Memory -- memory that contains the computer's operating instructions (programs). It also stores general information that tells the computer how various components should perform under specific operating condition.
- Roo bar
- An Australian term for Nerf bar.
- Roof panel
- The horizontal outer layer of the sheet metal roof panels that is spot-welded along its edges to the top of the roof door and screen pillars.
- Roof pillars
- The steel pillars that surround the front and rear windshields and front and rear doors in a sedan. Pillars between the windshield and the front door are referred to as A-pillars. Pillars between the front and rear doors are referred to as B-pillars. Pillars between the rear doors and the rear windshield are called C-pillars. They provide greater rigidity to the car and making a hardtop possible.
- Roof rail
- A longitudinal side member above the doors to which the roof panel is attached. Also called "cantrail."
- Roof spoiler
- A spoiler attached to the roof of a truck cab, or vehicle towing a trailer or motor home, to reduce drag and increase stability.
- Room temperature vulcanizing sealer
- (RTV) semi-liquid, silicone rubber sealant which is proof against oil and water but not gasoline.
- Root
-
- The lowest point of a screw thread.
- That surface of the thread which joins the flanks of adjacent thread forms and is identical with or immediately adjacent to the cylinder or cone from which the thread projects.
Also see
- Roots compressor
- A typical lobe-type positive displacement compressor; uses a pair of two-lobed or three-lobed internal rotors phased to prevent clashing of the lobes by gears; normally driven from the crankshaft by toothed or V-belts, can achieve speeds up to 10,000 rpm; provides low-end torque and boost without lag but is less fuel-efficient than a turbocharger.
- Roots supercharger
- A typical lobe-type positive displacement compressor; uses a pair of two-lobed or three-lobed internal rotors phased to prevent clashing of the lobes by gears; normally driven from the crankshaft by toothed or V-belts, can achieve speeds up to 10,000 rpm; provides low-end torque and boost without lag but is less fuel-efficient than a turbocharger.
- RO/RO ship
- A cargo or ferry ship on which trucks and other vehicles can be driven on and off on ramps through large openings at the bow, stern or side.
- Rotary
- A circle with streets coming off it like spokes in a wheel. Also called Traffic circle. The British call it a roundabout.
- Rotary compressor
-
- A compressor which has rotating rotors, vanes, or eccentric mechanisms that compress and pump refrigerant.
- Mechanism which pumps fluid by using rotating motion.
- Rotary disc valve
- A valve employed as an intake control in modern two-stroke engines, consisting of a thin steel disc attached to one end of the crankshaft. The intake port passes trough to the disc valve assembly, and thus is normally closed off by the disc. To permit induction at the correct part of the engine cycle, part of the disc is cut away, opening the intake port for the required duration, independent of the piston position.
- Rotary engine
- An Internal combustion engine which is not of a Reciprocating (Piston) engine design. There is no true Crankshaft, although the power-take-off shaft is sometimes called the Crankshaft. It is stationary or fixed in that it simply spins in place. The central Rotor turns in one direction only and yet produces the required Intake, Compression, firing and Exhaust strokes. Because it uses rotary motion instead of reciprocating motion, the rotary engine has better balance and less vibration than piston engines. Two common rotary engines are the Gas turbine and the Wankel.
- Rotary flow
- The movement of the oil as it is carried around by the Pump and Turbine in a Torque converter. The rotary motion is not caused by the oil passing through the pump, to turbine, to Stator, etc., as is the case with Vortex flow. Rotary flow is at right angles to the center line of the Converter whereas vortex flow is parallel (more or less depending on the ratio between the speeds of the pump and turbine).
- Rotary valve
- An engine or pump component forming part of a rotating assembly; may be designed as a cylindrical or a disc valve.
- Rotax®
- A trademark name of an Austrian manufacturer of two-stroke engines used in Ski-Doo® snowmobiles and Sea-Doo® watercraft.
- Roto cap
- A device fitted to some engines which turns a valve slightly every time it opens or closes, to prevent the valve sticking or burning. Also called Valve rotator.
- Rotoflex coupling
- One design of a flexible coupling in the shape of a hexagonal rubber
ring.
Also see
- Rotomill
- A process that removes the top few inches of asphalt in preparation for a new asphalt surface.
- Rotor
-
- Any component which rotates.
- A small rotating cap-like unit at the end of the distributor shaft. It is located on the Breaker cam inside the cap. It connects between the center Electrode and the various outer Spark plug terminals as it turns, thus distributing the high Voltage from the Ignition coil secondary winding to the proper Spark plug. Also called rotor arm.
- A rotating Armature inside a Stator. As the rotor turns within the stator, electricity is produced to power the electrical Components.
- The rotating member of an induction motor in a single-phase device. Current that is normally induced in the rotor reacts with the magnetic field produced by the stator. This produces torque and rotation.
- A trichoidal device in a rotary engine.
- A rotating displacement element of a rotary pump, such as a gear, screw, piston, etc.
- A moving part of a pulse generator. The opposite is stator.
- A rotating element of a Roots supercharger.
- The rotating part of a device, such as a disc-brake rotor.
- Rotor arm
-
A small rotating cap-like unit at the end of the distributor shaft. It is located on the Breaker cam inside the cap. It connects between the center Electrode and the various outer Spark plug terminals as it turns, thus distributing the high Voltage from the Ignition coil secondary winding to the proper Spark plug.
Rotor arm
- Rotor pump
- An engine oil pump in which an internal rotor, e.g., with four external lobes, is used to drive an eccentric external gear, e.g., with five internal lobe-spaces; operates in a similar way to gear pumps, but has higher pump capacity, and is quieter and more expensive.
- Rotor-type oil pump
-
An engine oil pump in which an internal rotor, e.g., with four external lobes, is used to drive an eccentric external gear, e.g., with five internal lobe-spaces; operates in a similar way to Gear pumps, but has higher pump capacity, and is quieter and more expensive.
Rotor-type oil pump
- Rotary Injection Pump
- A lower-cost injection pump used with pump-line-nozzle systems. The pump has a central plunger system (usually consisting of two opposing plungers) that provides fuel to every cylinder during the required injection period. A plate located near the top of the pump rotates, opening an appropriate orifice at the right time for distribution to each cylinder's injection nozzle through a separate line. It is usually used with automotive or agricultural engines that have lower performance and durability requirements than the heavy-duty truck diesels.
- Rotten-egg smell
- In cars equipped with catalytic converters, this smell is the result of an excessively rich air/fuel mixture.
- Roughing dolly
- A curved block of cast iron for shaping panels. Since it weighs about 2 kg (4-1/2 lb), it can be used as light weight sledge, yet it is heavy enough to be used in most autobody applications. It is U-shaped to provide a variety of surfaces that can be used as a dolly or a hammer. One edge is formed so it can be used for forming a bead on a fender.
- Roundabout
- A British term for a Traffic circle.
- Roundhead machine screw
-
A machine screw where the base of the head is flat to fit flush with the surface of the material and the top of the head is dome shaped.
Roundhead machine screw
- Round hump
- A safety contour on both rim bead seats preventing the tire from
sliding into the rim well.
Also see
- Route
-
- The direction or path that wiring or a cable takes.
- To feed wiring or cable into a certain direction or path.
- The roadway that a vehicle takes from one point to another.
- Royaum
- A model of automobile manufactured by Buick Division of General Motors from 2005