DICTIONARY OF AUTOMOTIVE TERMS - "Ro"

Road

Any large path upon which vehicles travel.

Also See
Frontage road
Gravel road
Green Stamp Road
Non-national road
Pioneer roads
Pit road
Primary and secondary roads
Rolling road
Toll road

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

Road Construction sign

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 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 course

A closed course with turns to both the right and the left mimicking a normal road.

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 fund license

A British license showing that road tax has been paid.

Road hazard

Injury to a tire sustained in normal operation, excluding collision or vandalism and that is not reparable by accepted standards.

Road hog

A selfish, often aggressive driver.

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.

Roadie

A bicycle rider who prefers riding on paved surfaces.

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.

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).

Road speed

A vehicle's speed along a road, measured in mph or kph.

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
Sport roadster.

Road surfaces

See
Split-friction road surfaces.

Road tax

An annual tax paid in order to use a vehicle on the roads.

Road test

1. A test to check that a car is roadworthy after repair.
2. A test of a car (e.g., a new model) in actual use; for example, by a magazine for comparison with other models.

See also Test drive.

Road-test

To give a vehicle a Road test.

Road tire

A bicycle tire that is usually 700C or 27 in. sizes with a non-aggressive tread.

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.

Roadworthiness

A vehicle which is fit to be driven on the roads.

Roadworthy

A mechanically sound vehicle which is fit to be driven on the roads.

Roamer

A vehicle brand of which the 1925 8-88, 6-54e, 4-75; 1926 4-75e and 8-88; 1927; 1928; 1929 8-88; 1929 8-125; and 1930 8125 models are Classic cars.

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.

Robot

See
Painting robot.

Robot spraying

The application of paint by robots.

Rochet-Schneider

A vehicle brand of which the 1925-1948 models with required application are Classic cars.

Rocker

See
Brush Rocker
Closing rocker
Forked rocker arm
Forked rocker
High lift rocker arms
Opening Cam rocker

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.

Also See
Adjustable Rocker Arm
Ball joint rocker arm
Forked rocker arm
High lift rocker arms

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
Valve cover.

Rocker arm shaft

The shaft upon which the Rocker arms are mounted so that the rocker arms can pivot. Also called rocker shaft.

Rocker Arm Stud

See
Notched Rocker Arm Stud

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

1. The shaft on which the rocker arm pivots
2. A British term for Cross shaft (i.e., the outgoing shaft of the steering gearbox, to which the pitman arm is connected).

Rocket

See
Booster
Crotch rocket

Rocking

See
Piston slap.

Rocking chair

Trucker slang for vehicle between 2 trucks as in "Who we got in the rocking chair tonight."

Rockwell hardness

A measurement of the degree of hardness of a given substance.

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

1. A modified car, i.e., Street rod.
2. To drive a vehicle hard.
3. A Connecting rod.
4. To clean out a Radiator by passing a rod through the lines by Rodding the radiator.
5. 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

Rod arm

See
Steering arm

Rod bearing

See
Big-end bearing
Connecting rod bearing

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.

Rod end

The ends of connecting rods which fit over crank pins or cross head pins.

Also see
Tie rod ends.

Rod engine

See
Pushrod engine.

Rod mounting box

See
Panhard rod mounting box.

Rod puller

See
Tie rod puller.

Rod separator

See
Tie rod separator.

Rod shank

See
Connecting rod shank.

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.

Also See
Anti-roll bar
Body roll
Integrated roll cage
Period of roll
Rollbar
Roll cage
Roll center
Roll steer
Roll stiffness

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 axis

Roll axis

The axis through the front and rear roll centers.

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
Anti-roll bar.

Roll cage

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.

Also See
Integrated roll cage

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.

Roll coating

An application method for organic or chemical conversion coatings using rolls.

Rolled bead

See
Beaded edge.

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

1. A device for replacing sliding Friction with rolling friction.
2. While ball bearings use a series of balls in a cage, roller bearings use a series of small cylinders.
3. A colloquial term for a Rolls-Royce.

Also See
Cam roller
Sheet metal roller
Tread roller
Worm and roller

Roller bearing

Roller bearing

An anti-friction bearing using a series of straight, cupped, or tapered steel Rollers engaging an inner and outer ring or Race.

Also See
Tapered roller bearing
Timken® roller bearing

Roller cage

A metal or plastic enclosure which keeps the rollers in place in a roller bearing.

Rollercam brake

See
Rollercam brakes.

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 cell pump

See
Roller-vane pump.

Roller chain

A power-transmitting chain in which each link consists of two free-moving rollers located by pins connected to sideplates.

Also see
Duplex chain
Simplex chain
Triplex chain

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
Stator roller clutch

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
Rolling road.

Roller foot lever

See
Roller tappets.

Roller leveling

A process in which steel strips pass rollers which remove excess zinc after the actual immersion process of galvanizing has begun.

Roller lifter

See
Roller tappets.

Roller lifters

See
Roller tappets.

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 seat

Roller seat

A mechanic's stool on wheels

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 tappet

See
Roller tappets.

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
Vane pump.

Rolling

See
Free rolling wheel
Temper rolling
Thread Rolling

Rolling bearing

See
Antifriction bearing.

Rolling circumference

The circumference of a fully inflated tire under load.

Rolling contact

See
Continuous rolling contact

Rolling friction

A rolling bearing's frictional resistance to rotation.

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.

Rolling wheel

See
Free rolling wheel.

Roll-off

See
Tire roll-off.

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
Spiral wrapped pin.

Roll resistance

See
Roll stiffness.

Rolls

Acronym for Rolls Royce.

Also see
Bending Rolls
Billet Mills
Mixing rolls

Rolls-Royce

Click image for books on
Rolls-Royce

A vehicle brand of which the 1925-1948 models are Classic cars. All the 1947-67 models are Milestone cars.

Rolls Royce mascot

See
Emily.

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 steer effect

See
Roll steer.

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.

Romeo

See
Alfa-Romeo.

RON

Acronym for Research Octane Number

Also see
Octane number.

Roo bar

An Australian term for Nerf bar.

Roof

See
Pagoda-style roof
Pagoda roof
Pent-roof
Ponded Roof
Queen Post Roof
T bar roof

Roof air spoiler

Roof air spoiler

A spoiler located on the back of the roof of a van

Roof box

An enclosed, multi-purpose roof carrier.

Roof brace

A transverse rail that supports the roof panel; there are usually several roof braces.

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 rack

Roof rack

A luggage rack on the roof of a vehicle.

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

See
Machine Room

Room temperature vulcanizing sealer

(RTV) semi-liquid, silicone rubber sealant which is proof against oil and water but not gasoline.

Root

1. The lowest point of a screw thread.
2. 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
Crest
Thread root
Veeder root

Root diameter

The minor diameter on screws or the major diameter on nuts.

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.

Rope

See
Cable-laid Rope
Hoisting rope
Wire Rope

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.

Rosette weld

See
Plug weld.

Rotary

A circle with streets coming off it like spokes in a wheel. Also called Traffic circle. The British call it a roundabout.

Rotary blade compressor

Mechanism for pumping fluid by revolving blades inside cylindrical housing.

Rotary compressor

1. A compressor which has rotating rotors, vanes, or eccentric mechanisms that compress and pump refrigerant.
2. 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 hammer

A power hammer.

Rotary pump

A pump with rotating members.

Rotary valve

An engine or pump component forming part of a rotating assembly; may be designed as a cylindrical or a disc valve.

Rotary vane pump

See
Vane pump.

Rotate tires

See
Tire rotation.

Rotating seal ring

A rotating element of a mechanical seal.

Rotation

The motion of a body about an axis within the body.

Also See
Direction of rotation
Tire rotation
Wheel rotation

Rotational atomization unit

A painting unit equipped with rapidly rotating spray bells.

Rotator

See
Valve rotator.

Rotax®

A trademark name of an Austrian manufacturer of two-stroke engines used in Ski-Doo® snowmobiles and Sea-Doo® watercraft.

Rotbox

A colloquial term for a vehicle in very poor shape.

Also see
Rust bucket.

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
Doughnut coupling.

Rotomill

A process that removes the top few inches of asphalt in preparation for a new asphalt surface.

Rotor

1. Any component which rotates.
2. 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.
3. A rotating Armature inside a Stator. As the rotor turns within the stator, electricity is produced to power the electrical Components.
4. 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.
5. A trichoidal device in a rotary engine.
6. A rotating displacement element of a rotary pump, such as a gear, screw, piston, etc.
7. A moving part of a pulse generator. The opposite is stator.
8. A rotating element of a Roots supercharger.
9. The rotating part of a device, such as a disc-brake rotor.

Also See
Auxiliary Rotor
brake disc
Brake rotor
Cage Rotor
Clutch Rotor
Dished Rotor
Distributor rotor
Eccentric rotor pump
Pump rotor
Solid Brake Rotor
Timing rotor
Toothed Signal Rotor
Ventilated Rotor

Rotor arm

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 hat

The raised center section of some brake rotors which gives the rotor the shape of a hat.

Rotor Member

See
Nondisplaceable Rotor Member

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.

Also see
Eccentric rotor pump
Gear pump
Internal gear pump

Rotor-type oil pump

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.

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.

Rotovalve

See
Thompson rotovalve.

Rotowelding

See
Friction welding.

Rotten-egg smell

In cars equipped with catalytic converters, this smell is the result of an excessively rich air/fuel mixture.

Rough

The sound or condition of an engine which is running unevenly.

Roughening

A mechanical or chemical treatment of a surface to produce minute irregularities.

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.

Roughing stone

A coarse stone used for quick removal of material during honing.

Round

See
Outboard round hump
Out of round

Roundabout

A British term for a Traffic circle.

Roundel

See
BMW roundel.

Round file

A file in the shape of a round bar, rather than a blade.

Round Head

Semi-elliptical top surface and flat bearing surface.

Round head bolt

A general term including carriage bolts, cup head bolts, and mushroom head bolts.

Roundhead machine screw

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.

Round hump

A safety contour on both rim bead seats preventing the tire from sliding into the rim well.

Also see
Outboard round hump.

Route

1. The direction or path that wiring or a cable takes.
2. To feed wiring or cable into a certain direction or path.
3. The roadway that a vehicle takes from one point to another.

Routine

See
Check routine.

Rover

Click image for books on
Rover

A model of automobile manufactured in the UK

Also See
Land Rover
Range Rover

ROW

See
Right-of-Way

Royal Automobile Club

(RAC) A motoring organization in the UK.

Royce

See
Rolls-Royce
Rolls Royce mascot

Royce mascot

See
Rolls Royce mascot