Dictionary of Automotive Terms Abbreviations

DICTIONARY OF AUTOMOTIVE TERMS - "Ri"

Rib

The continuous raised portions of rubber that run circumferentially (straight or in a zigzag pattern) making up the tread on the tire. Also the term applies to various raised surfaces circling the sidewall, i.e., guide rib.
A structural member for reinforcing bodywork.

Also See
Scuff rib
Tread rib

Ribbing

A series of raised portions in castings or moldings to increase rigidity.
A narrow recess stamped into relatively flat body panels, e.g., floorpans, that helps to reinforce the panel and to suppress vibrations in it.

Ribbon silicon: Crystalline silicon that is used in photovoltaic cells. Ribbon silicon is fabricated by a variety of solidification (crystallization) methods that withdraw thin silicon sheets from pools of relatively pure molten silicon.

Ricardo principle: An arrangement in which a portion of the Combustion chamber came in very close contact with the Piston head. The other portion, off to one side, contained more space. As the Piston neared TDC on the Compression stroke, the fuel mixture was squeezed tightly between the piston and Head thus causing the mixture to squirt outward into the larger area in a very turbulent manner. This produced a superior mixture and allowed Compression ratios to be raised without Detonation.

Rich: An air/fuel mixture that has more petrol than normal. The opposite is lean.

Rich air-fuel mixture: A mixture of air and fuel in which there is less air and more fuel. See Air-fuel ratio.

Rich mixture: A mixture of air and fuel in which there is less air and more fuel. See Air-fuel ratio. The opposite is lean mixture. Also compare Stoichiometric ratio. A slightly rich mixture generates the maximum achievable engine power, an overly rich mixture causes spark plug fouling, loss of engine power, and excessive fuel consumption. Any rich mixture increases exhaust emissions.

Ride: The degree of comfort, especially with regard to the suspension, experienced by the passengers. Also see Electronic ride control.

Ride control: See
Electronic ride control.

Ride height: A measurement between the ground and some fixed reference point on a car's body. The exact location of the fixed point varies among manufacturers. This dimension can be used to measure the amount of Suspension deflection or the height of the body from the ground. See Ground clearance.

Ride-height adjuster: See
Ground clearance control.

Ride levelling: See
Automatic level control.

Rider

A person who operates a motorcycle.
A passenger (but generally not the driver) of a car or truck.
A vehicle. See Low rider.

Ride steer: A generally undesirable condition in which a wheel steers slightly as its Suspension compresses or extends. Also called bump steer.

Ridge

An edge, ledge, or lip which protrudes beyond the normal face of an object. See Rim ridge.
The cutting edge of a screw thread above the flanks.
See Pressure ridge.
A Hump.

Also See
Piston ring ridge
Burr

Riding the clutch: A situation where the Driver rests his foot on the Clutch pedal while the vehicle is being driven. This action can cause undue wear on the clutch plates because they may be rubbing against each other ever so slightly.

Riding two up: Carrying a passenger on your bike.

Rig: A large truck.

Also See
Big rig
Jury rig

Rigged: See
Jerry rigged
Jury rigged

Rigger: See
Out-rigger.

Right: When referring to the side of a unit, the right side is always from the perspective of operation. In other words, when sitting in the driver's seat or when riding a bicycle or when pushing a mower, the right side is the operator's right hand side. In other words the left or right side is determined by facing the rear of the unit.

Right-hand drive: (RHD) A steering system in which the steering wheel is located on the right-hand side of the vehicle; used for driving on the left, as in the UK, Japan, Australia, etc. The opposite is Left-hand drive.

Right hand thread: See
Right-hand thread.

Right-hand thread: The common direction (Clockwise) which is used to secure a nut to a bolt.
Also See
Left-hand thread.

Right hand turn signal: Right Hand Turn Signal

A device which is attached to the turn signal lever on the left side of the steering wheel to allow disabled people to operate the turn signals from the right side.

Rights: See
Intellectual property rights.

Right turn sign: Right turn sign

A traffic sign indicating that the road makes a sharp turn to the right

Rigid: Inflexible, without any flexural or elastic characteristic.

Rigid axle: A simple non-independent Suspension, consisting of a rigid transverse member with wheel hubs solidly bolted to it. The axle can be attached to the body by Leaf springs, or by a combination of suspension arms and links. A rear axle which may be either live (in rearwheel drive cars) or dead (in front-wheel drive cars).

Rigid axle connection: Fixed drive.

Rigidity: See
Torsional rigidity.

Riley: A vehicle brand of which the 1925-1948 models with required application are Classic cars. The 1945-55 2.5 (RMA, RME) models are Milestone cars.

Rim

The outer edge of a dented area in a body panel that is heat shrunk towards the center of the dent.
On a Bicycle, the metal or wooden hoop of a wheel that holds the tire and tube and the outer ends of the Spokes.
On a truck, the metal assembly consisting of a base and either a side ring or a side and lock ring combination, which are removable from one side for tire mounting. The opposite side has a fixed flange to retain the tire. Note Passenger and tubeless rims do not have removable side and lock rings.

Also See
Ah rim
Asymmetric rim
Base rim
Center rim
Curing rim
DC rim
Demountable rim
Detachable rim
Drop-center rim
Drop-centre rim
Drop center rim taper
Drop center rim
Drop centre rim
Flat base rim taper
Flat base rim
High center rim
Horn rim steering wheel
Hump rim
Intermediate rim taper
Multi-piece rim
Nominal rim diameter
Nominal rim width
One-piece rim
One-piece rim designation
Overall rim diameter
Removable rim
Safety rim
Semi-drop center rim
Single-piece rim
Split rim
Standard rim
Symmetric rim
Td rim
Tr-denioc rim
Tr rim
Well-base rim
Wheel rim
Wheel trim rim

RIM: Acronym for Reaction injection molding.

Rim bead seat: The portion of the wheel rim below the rim flange providing radial support to the bead of the tire.

Rim bead seat taper: The narrowing of the rim width towards the rim well. The taper must be designed to lock the tire to the rim and provide a good seal; well-base rims for passenger cars have a 5° taper, those for commercial vehicles have a 15° taper; flat base rims for commercial vehicles have no taper.

Rim brake: Any type of brake that slows or stops a wheel by pressing its pads against the sides of the wheel Rim.

Rim designation: The nominal rim diameter, nominal rim width and any abbreviations and codes for the contour of the rim. Compare Multi-piece rim, and One-piece rim designation.

Rim diameter: The distance between the intersection of the bead seats and the vertical walls of the rim flanges.

Also See
Nominal rim diameter
Overall rim diameter

Rim drivers: Riveted or welded metal blocks or extrusions on both sides of the valve slot to prevent valve damage due to rim slippage on cast spokes.

Rim flange: The part of a rim that supports the tire bead in a lateral direction; the linear distance between the two rim flanges is termed rim width.

Rim offset: A measurement in inches from the center of the rim (between the flanges) to the tip of the 28° gutter bevel.

Rim pull: Actual amount of effort in pounds available at the point of contact of tire and road surface.

Rim ridge: See
Hump.

Rim size: The dimension of a wheel covering the rim width and rim diameter and is measured in inches.

Rim steering wheel: See
Horn rim steering wheel.

Rim strip: A thin, narrow strip of material (usually rubber or cloth) placed around the outside of a rim (beneath the tube) to cover the sharp edges of the spoke which might protrude beyond the nipple. See Rim tape.

Rim tape: A rubber strap which covers the spoke nipples on the inside of the rim to protect the spoke from poking into the tube.

Rim taper: The slope of the rim.

Also See
Advanced rim taper
Base rim taper
Center rim taper
Drop center rim taper
Flat base rim taper
Intermediate rim taper
Semi-drop center rim taper

Rim type: Depending on the type of tire, rim types differ according to the rim profile and the number of rim parts. Compare Multi-piece rim, One-piece rim, and Safety rim.

Rim well: The portion of the rim with a substantially smaller diameter than the bead seats and located with sufficient depth and width to enable the tire beads to be forced over the mounting side of the rim flange and bead seat taper for installation or removal.

Rim well base: The portion of the rim with a substantially smaller diameter than the bead seats and located with sufficient depth and width to enable the tire beads to be forced over the mounting side of the rim flange and bead seat taper for installation or removal.

Rim width: The nominal distance between the rim flanges. The width of a rim is an important factor in the handling characteristics of a car a rim that is too narrow in relation to the tire width will cause the tire to distort sideways under fast cornering. Unduly wide rims on an ordinary car tend to give a rather harsh ride because the sidewalls of the tire have insufficient curvature to make them flex properly over irregularities in the road. Also see Nominal rim width.

Ring: A circular piece or band of metal.

Also See
Balk ring
Blocking ring
Chainring
Chrome ring
Compression ring
Control ring
D-ring
D ring
Dykes ring
Fire ring
Flywheel ring gear
Fulcrum ring
Grooved compression ring
Heavy-duty ring wrench
Horn ring
L-section ring
Lockring
Lock ring pliers
Molybdenum piston ring
Moly ring
O-ring
Oil control ring
Oil ring
Pinned piston ring
Pinned ring
Piston ring clamp
Piston ring end gap
Piston ring expander
Piston ring flutter
Piston ring gap
Piston ring groove cleaner
Piston ring groove
Piston ring job
Piston ring pliers
Piston ring ridge
Piston ring side clearance
Piston ring stop
Piston ring
Pivot ring
Rectangular-section ring
Ring and pinion
Ringbolt
Ring gear
Rotating seal ring
Rubber ring
Scraper ring
Side ring
Slip ring
Snap ring
Spacer ring
Stepped compression ring
Tapered compression ring
Truarc retaining ring
Valve seat ring
Wear ring

Ring and pinion: Ring and Pinion

A term used to describe the Differential Drive pinion and Ring gear.
Also See
Final drive ratio
Ring and pinion

Ring belt: The lands and rings of a piston.

Ringbolt: An iron bolt having a ring through an eye at one end, through which a rope can be passed and tied.

Ring, chrome: See
Chrome ring

Ring clamp: See
Piston ring clamp.

Ring, compression: See
Compression ring

Ring end gap: See
Piston ring end gap.

Ring expander: Also See
Piston ring expander
Piston ring pliers

Ring flutter: See
Piston ring flutter.

Ring gap: The gap between the piston ring ends with the piston installed in the bore. See Piston ring end gap.

Ring gear

Ring Gear

The large bevel, circular gear which is attached to the Flange or Carrier of the Differential case. It meshes with the Drive pinion on the end of the Propeller shaft.
The outer gear in a Planetary gearset. Also see Flywheel ring gear.
Annulus gear.
See Crown wheel.
A toothed rim of a flywheel which engages the pinion of the starter motor.

Also See
Flywheel ring gear
Starter ring gear

Ring groove: See
Piston ring groove.

Ring groove cleaner: See
Piston ring groove cleaner.

Ring groove insert: See
Top ring groove insert.

Ring job: See
Piston ring job.

Ringlemann scale: Device for measuring smoke density.

Ring, pinned: See
Pinned piston ring

Ring pliers: See
Lock ring pliers
Piston ring pliers

Ring ridge: See
Piston ring ridge.

Rings: See
Piston ring
Whitewall rings.

Ring side clearance: See
Piston ring side clearance.

Ring spanner: A British term for a Box wrench.

Ring stop: See
Piston ring stop.

Ring wrench: See
Heavy-duty ring wrench.

Rinse: See
No rinse treatment.

Rinse treatment: See
No rinse treatment.

Ripping hammer: A hammer which looks like a claw hammer, but the claw is straight.

Ripple current: The undesirable AC (ripple) component of a pulsating DC current produced by a rectifier or similar power conditioning device.

Rise: See
Dead rise.

Riser: See
Handlebar riser
Heat riser

Riser bars: A mountain bike handlebar that features an upward sweep providing a more upright riding position and greater stability.

Riser valve: Device used to manually control flow of refrigerant in vertical piping.

Rising rate: A suspension system that becomes harder to compress the farther it is compressed. This is usually achieved by a mechanical linkage with variable leverage ratio.

Rising rate suspension: See
Rising-rate suspension.

Rising-rate suspension: A Suspension system where the spring rate increases when the wheels move further into Jounce. This action can be accomplished by configuring the geometric shape of the suspension, by using springs which change tension as they are compressed, or by using two or more springs with rubber stops. The purpose of a rising-rate suspension is to maintain consistent ride and handling characteristics under a variety of situations loaded or unloaded, straight roads or curves, and smooth roads or bumpy.

Rivet

A metal pin used to hold two objects together. One end of the pin has a head and the other end must be set or Peened over to create another head
A semipermanent fastener used to hold two pieces together.

Also See
Blind rivet
Pop rivet

Riveted brake lining: A brake shoe that is attached to the backing plate with rivets rather than glued on.

Riveted linings: Brake linings that are riveted to the pad backing plate or brake shoe with copper or aluminum rivets.

Riveter: A tool with pliers-like handles and nose piece to insert rivets. It is used, for example, in body repair work to rivet sheet metal material together.

Rivet gun: A tool with pliers-like handles and nose piece to insert rivets. It is used, for example, in body repair work to rivet sheet metal material together.

Riveting hammer: A hammer with a special head for securing rivets.

Riviera: Click image for books on
Buick Riviera

A model of automobile manufactured by Buick

Rivnut: Rivnut

A one-piece internally threaded and counterbored tubular aluminum rivet that can be pulled up or headed while working entirely from one side, forming a bulge or head on the blind side. This upset is large enough to resist being pulled through metal or plastic even under conditions of eccentric load. It overcomes the difficulty of installing brackets, handles or other attachments to tubular pieces.