Glossary “unicast rotor” Definition:
Type of rotor used on man late-model cars having the rotor and hub cast as one integral component, often from gray iron rather than cast iron.
unicast
Glossary “unicast” Definition:
Component or part cast as a single unit.
unibody design
Glossary “unibody design” Definition:
Chassis design that has a floorpan and a small subframe section at the front and the rear.
unibody
Glossary “unibody” Definition:
Short term for unit body. Type of construction where body parts are welded and bolted together to form an integral frame. Lighter, thinner, high-strength steel alloys or aluminum alloy is used.
UNF
Glossary “UNF” Definition:
Unified National Fine. Identifying a standard thread pitch and count.
unequal length control-arm suspension
Glossary “unequal length control-arm suspension” Definition:
Front suspension-control arms of unequal length to compensate for jounce and rebound.
unequal A-arms
Glossary “unequal A-arms” Definition:
A suspension system where one arm is larger than the other.
UNEP
Glossary “UNEP” Definition:
United Nations Environment Program.
undertread compound
Glossary “undertread compound” Definition:
Blend of synthetic rubbers used in the material under the tire tread.
understeer
Glossary “understeer” Definition:
Condition where the front of the vehicle tends to break out and slide toward the outside of a turn.
undersquare
Glossary “undersquare” Definition:
When the bore is less than the stroke.
underspeed mode
Glossary “underspeed mode” Definition:
Control mode that prevents the engine from stalling in the event it stumbles while running. Also used during engine crank.
underslung suspension
Glossary “underslung suspension” Definition:
A suspension system in which the spring is positioned under the axle.
undersized bearing
Glossary “undersized bearing” Definition:
Bearing made thicker than standard. It has a smaller inside diameter to fit an undersized crankshaft.
undersize (US)
Glossary “undersize (US)” Definition:
Part of item that is smaller than that specified.
undermasked
Glossary “undermasked” Definition:
An area that must be cleaned with solvent or polishing compound to remove overspray.
underinflation
Glossary “underinflation” Definition:
Condition with respect to tire inflation that decreases the rolling diameter and increases the contact area, which results in excessive sidewall flexing and tread wear causing excessive heat buildup, ultimately leading to severe tire damage.
underfill
Glossary “underfill” Definition:
Depression on the weld face or root surface extending below the adjacent surface of the base metal.
undercutting
Glossary “undercutting” Definition:
Removing too much primer-surfacer when sanding.
undercut
Glossary “undercut” Definition:
A weld condition where the base metal is burned away, below the surrounding area.