Glossary “rocking couple” Definition:
Another form of vibration that ocurrs when there are only two cylinders that fire 180¡ã apart instead of 360¡ã apart. Vibration or unbalance set up by a alternating rising and falling of two masses that are out of phase.
r
roadability
Glossary “roadability” Definition:
The steering and handling qualities of a vehicle as it is being driven on the road.
rocker arm
Glossary “rocker arm” Definition:
1). A pivoting part in a mechanical fuel pump, one end of which rides on a camshaft eccentric or pushrod, and the other end of which pulls on the diaphragm via a mechanical linkage, causing the diaphragm spring to be compressed. 2). A pivoting lever in the valve train of an overhead valve system which applies motion, directly or indirectly from the camshaft to open an intake or exhaust valve.
road horsepower
Glossary “road horsepower” Definition:
Horsepower available at the drive wheels of the vehicle.
road load
Glossary “road load” Definition:
Horsepower needed for a vehicle to maintain speed against wind resistance, rolling resistance from the tires and terrain.
road test
Glossary “road test” Definition:
The study which is made by driving the vehicle in order to determine that it is working or not working properly.
road feel
Glossary “road feel” Definition:
Term that relates to the driver’s ability to sense the vehicle’s directional control from the movement transmitted through the steering wheel by the front wheels; not as sensitive on power-steering equipped vehicles.
RO
Glossary “RO” Definition:
Repair Order.
roach coach
Glossary “roach coach” Definition:
A catering vehicle.
road draft tube
Glossary “road draft tube” Definition:
A pre-emission control era device for ventilating the crankcase to the atmosphere; a pipe routed under the chassis at an angle that produces a small vacuum as the vehicle travels forward. Fresh air is drawn in through a mesh filter in the oil filler cap, circulated around inside the crankcase and exhausted through the road-draft tube carrying blowby with it.
RM
Glossary “RM” Definition:
Relay Module. A module containing two or more relays.
RMA
Glossary “RMA” Definition:
Rubber Manufacturers Association.
RMS
Glossary “RMS” Definition:
Root Mean Square
R-L
Glossary “R-L” Definition:
Right or Left
RLC
Glossary “RLC” Definition:
Reverse Lamp Control
rivet
Glossary “rivet” Definition:
Type of fastener used to hold two pieces together.
rivet gun
Glossary “rivet gun” Definition:
Tool used to install pop rivets.
riveted lining
Glossary “riveted lining” Definition:
Linings on drum brake shoes or disc brake pads that are attached to their steel backing with rivets.
RKE
Glossary “RKE” Definition:
Remote Keyless Entry Sysem and Module
ring tension
Glossary “ring tension” Definition:
Natural spring tension of the piston ring. Helps the ring seal against the cylinder wall during the intake and exhaust stroke and the beginning of the compression stroke, when compression gases are not forcing the rings against the cylinder walls.