DICTIONARY OF AUTOMOTIVE TERMS - "Of"

O/F
Acronym for Oxygen to Fuel ratio
Off-boost
The condition that exists when a turbocharger is not producing power. If exhaust pressure is not sufficient to spin the turbine, the turbocharger goes off boost.
Off-car balance
A procedure of removing a wheel from a vehicle and balancing the assembly. This is the most common form of wheel balancing and is done either Statically or Dynamically. The preferred method of off-car balancing is dynamic.
Off color
A color mismatch (though very close to the correct color) due to wrong paint mixing or application
Off cycle
Segment of refrigeration cycle when system is not operating.
Offer up
To bring a part close to or in contact with another, ready to fit the pieces together
Off-highway use
Includes petroleum products sales for use in:
  • Construction equipment including earthmoving equipment, cranes, stationary generators, air compressors, etc.
  • non-Construction equipment such as logging
  • But not farm use of petroleum -- instead see Farm use
Off-highway vehicle
Vehicle intended for operation on unmade surfaces or rough terrain (i.e., for construction or agriculture).
Office of Mobile Sources
Division of EPA that proposes, promulgates and enforces regulations to control emissions of NAAQS pollutants and precursors from motor fuels and vehicles.
Office of Motor Carriers
(OMC) an interstate heavy truck and bus regulatory agency.
Off-idle Air Bleed
Off-idle discharge 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 Transfer ports
Off-lease
A vehicle which was once leased, but now has been returned after the lease has expired.
Off-line
Something that is independent of the main production process line which is characterized by a separate operation
Off-line painting
The painting of parts, mostly plastic parts, outside the actual painting line
Off-Road Bicycle Association
Off-road tire
(OTR) A tire that is used on vehicles designed for operation on unmade surfaces or rough terrain (i.e., for construction or agriculture or recreation).
Also see
Off-road vehicle
Vehicle intended for operation on unmade surfaces or rough terrain (i.e., for construction or agriculture).
Offset
  1. Something set at an angle or to one side.
  2. The Scrub radius.
  3. The distance between the centerline of the rim and the attachment face of the wheel disc at the wheel hub; this dimension can either be positive, negative, or zero. An important measurement for positioning the tire to insure proper tracking of the vehicle and adequate dual spacing.
Offset angle
The angle of the offset crankpins in V-engines
Offset crankshaft
A crankshaft layout whereby the axes of the crankshaft and the piston pin do not intersect. They do not intersect because the forces acting on the piston do not act uniformly on the walls of the cylinder through the skirt of the piston but much more on the side affected by the thrust of the con red during the power stroke. The crankshaft is thus offset, so that the con rod is less inclined during the power stroke than during the compression stroke
Offset dish
A wheel with a hub which is not in the same plane as the rim.
Offset handle
A drive handle for use with sockets, with one end set at 90° to the handle
Offset link
Offset link

Offset link

A link in a Chain which is often called a Half-link. An offset link increases the number of links by one.
Offset open-end wrench
Offset screwdriver
A screwdriver with either straight or Phillips (cross-head) tips or a combination of both, and the two ends set at right angles to the shank, somewhat in the shape of the letter Z
Offset steering
Offset twin
A typical motorcycle engine with the two crankpins offset by 180°
Offset wrench
An L-shaped tool for turning recessed screws
Off shade
A color mismatch (though very close to the correct color) due to wrong paint mixing or application
Offside
(o/s) The side of the vehicle farthest away from the curb (when driving)
Off-the-car balancing
Balancing the wheel after it has been removed from the car. The opposite is On-the-car balancing
Off-the-dolly panel beating
A metalworking technique used to hammer out dents in the bodywork. If the panel has a depression on one side, the dolly is held behind the depression, and the hammer blows are directed on the ridge away from the dolly, i.e., on the other side of the dolly. This causes a reaction by the dolly, producing an alternating impact on the dent from both sides