The reactions in the drive train or, in FWD vehicles, in
the steering, due to sudden load alteration. Compare
torque steer
Load and inflation table:
A chart in the tire manufacturer's data book listing the carrying capacity of a
tire at each of several air pressure increments from the lowest range of practical
usage to its maximum capacity.
Load at installed height:
The specified range of force required to compress a spring to its installed
height usually expressed in terms of so many pounds of force at so many inches
Load base:
Used in calculating load distribution; it is the distance between the center of
the rear axle (or center between tandem axles) and the center of payload. Also See: negative load base.
The distribution of load on truck or trailer chassis. The relationship of the
gross load on the front and rear axles to the total gross load.
Load distribution calculation:
The payload on the front axle is equal to the total payload multiplied by the
"load base" (in inches) and divided by the
"wheelbase" (in inches). To complete the calculation
of load per axle, it is necessary to obtain the unladen weight of the vehicle and
estimate its breakdown by axle.
The displacement of a ship when floating at her greatest allowable draft
Loaded radius:
Measurement in inches from the wheel axle centerline to the ground when the tire
is properly inflated for the load. Also called
static loaded radius
Loaded runout:
Radial runout that appears only when the tire is supporting the mass of the car.
Loaded runout is caused by stiff sections accidentally built into the tire sidewall.
Loaded tourer:
A bicycle whose structure, geometry, and equipment
is designed to allow a cyclist to travel with 50 pounds of gear.
The floor of the luggage area of an station wagon or hatchback
Load floor extension:
A molded tray that folds out of the rear luggage area and provides an extended
load floor which hangs out over the bumper. It can also be used for picnics.
The distance a load extends beyond the rear of a vehicle. It also requires a red
flag or red reflector at the end of the load.
Load proportional brake control:
A system or device which regulates the input force to the brakes on an axle
in proportion to the load on that axle.
Load range:
An index of tire strength which replaces the older
(discontinued) ply rating system.
A discontinued measurement of the number of
plies at which a tire is rated. Load
range B equals 4 ply rating; C equals 6 ply rating; and D equals
8 ply rating.
(LSPV) a hydraulic system control valve that works like a proportioning valve,
but also takes into consideration the amount of weight carried by the rear axle
Load-sensitive proportioning valve:
A valve which regulates hydraulic pressure to the rear wheels as a function of
chassis height-to-axle distance. A vehicle weight transfer during hard braking
increases this distance and, via a spring or rod linkage, will close the valve to
reduce braking pressure at the rear wheels; also, a heavily loaded car will have
more braking power at the rear wheels
A test applied to a battery. Although the battery indicates 12 volts or more, it may not meet the amperage for which it is rated. A tester with a variety of amperage loads can be applied to determine if the battery is good.
The changing of the amount of load distributed to each axle while the vehicle is in motion, due to the effects of braking, cornering ascending, or descending grades, etc. See rollsteer.
Load waterline:
The line on the lines plan of a ship, representing the intersection of the ship's form with the plane of the water surface when the ship is floating at the summer freeboard draft or at the designed draft. Also called marks
Lobe:
An off-center or eccentric enlargement on a shaft which converts rotary motion to reciprocating. Also called a "cam." See cam lobes.
A galvanic cell resulting from differences in potential between adjacent areas on the surface of a metal immersed in an electrolyte
Localized controllers:
Independent energy control device located near the system it is controlling.
Localized corrosion:
Rusting occurring at one part of a metal surface at a much higher rate than over the rest of the surface, e.g., pitting corrosion, crevice corrosion. The opposite is uniform corrosion
Local yokel:
Trucker slang for City police officer as in "That town up ahead is crawling with local yokels."
Local yokel with a customer:
Trucker slang for City police officer with someone pulled over as in "You've got a local yokel with a customer on your side."
A projection or pin for holding a part in a specific position. All engine bearings have some means of ensuring that they will not shift or move in the housing bore once installed. Most bearings utilize a locating lug, which is simply a small projection or pin that fits into a recess in the housing bore
Locating pin:
A projection or lug for holding a part in a specific position. Also See: dowel pin locating lug
Locating spring:
A steel wire clip in disc brakes that secures the cylinder in a floating frame or caliper frame. Compare spreader spring
Lock:
A fastening device which closes and opens by the use of a key.
A steering term describing the amount by which the wheels of a vehicle are able to turn. See steering lock and lock-to-lock.
To fix or become fixed in a certain position such as "the seat belts locked when the brakes were applied suddenly but so did the wheels and the car went into a skid."
A gear train term indicating to interlock or couple.
A cylinder in the middle of a cylinder lock that is prevented from turning (locked) by a number of pins (typically five) which penetrate down through the wall of the cylinder. The cylinder is turned by inserting a key which pushes the spilt pins up to varying heights so that the edge of the cylinder engages with the gap between the two sections of each pin allowing the cylinder to turn
Lock de-icer:
A fluid which is inserted into the key-hole to melt the ice which has bound the
tumblers in a door lock. Also See: door lock de-icer
Locked-rotor current
Steady-state current taken from the line with the rotor at standstill.
Steady-state current means the current does not vary in intensity, but remains
constant
Locked-rotor torque:
The minimum torque that an electric motor will develop at rest for all angular
positions of the rotor
Locking clamp with sliding jaw providing extended clamping capabilities
Locking clamp:
Locking pliers with specially shaped jaws for vice work and intricate clamping jobs. Locking clamps include, for example, vice grip C-clamps, vice grip pipe clamps, locking bar clamps, welding clamps, and sheet metal clamps
Locking differential:
A differential with the ability for locking together the two half shafts, thus putting the differential out of action and greatly improving traction. In a non-locking differential if one wheel was stuck in snow and spinning, the other wheel would be stationary even if it were on dry ground. In a locked differential, both wheels would turn the same amount. Since the dry-ground wheel had traction, it would be able to pull the vehicle out even though the other wheel had no traction.
An anti-theft wheel lug bolt which requires a special wrench to remove it
Locking lug nut:
An anti-theft wheel lug nut which requires a special wrench to remove it
Locking mechanism:
A device which locks the reel of a seat belt when the forward acceleration of the occupant exceeds a certain value
Locking pliers:
A type of pliers with locking jaws that can be used as pliers, wrench, clamp, or
small vice. Closing the handles locks the jaws into position. The jaws are released
by pulling a special release lever. Locking pliers with specially shaped jaws for
vice work and intricate clamping jobs are called
"locking clamps" Also See: action locking pliers parallel action locking pliers
Locking reel:
A device which locks the reel of a seat belt when the forward acceleration of the occupant exceeds a certain value
Locking synchromesh:
A common synchromesh mechanism in which the synchromesh pressure is proportional to the gearchange force, thus preventing overriding of the synchromesh action due to hasty operation of the lever; the gear and gearchange sleeve are prevented from engaging until rotational speeds are synchronized
A nut used in conjunction with a washer or a second nut to lock a mechanism in place, such as the nut found at the upper end of a headset and in front of the calipers on many caliper brakes. Also See: center lock nut nylon lock nut
Brand name for a type of liquid which is applied to the threads of a bolt and/or nut to secure them to various degrees of strength.
Lock-to-lock:
A steering designation which describes the distance created by the steering wheel when it is fully to the left and then moved fully to the right.
Lockup:
The moment when a tire begins to
skid during braking. A tire's maximum braking force
occurs when it is on the verge of lockup. Ideally all four tires should
approach lockup simultaneously to give a vehicle the best braking. Because
this ideal is hard to create in the real world, one end tends to lock up
before the other. Front-wheel lockup is inherently more stable than rear-wheel
lockup. Anti-lock brakes provide the best type of braking because it rapidly
releases pressure on the brakes to prevent lockup.
A condition where the wheel and tire is prevented from rotating.
Braking power overcomes the traction of the tires and skidding occurs.
Lock-up clutch:
Automatically engaged clutch in a lock-up torque converter which prevents slipping losses. Also See: torque converter lock-up clutch
Lockup differential:
A differential whose two outputs can be locked together, eliminating any differential action but maximizing traction under slippery conditions.
Lockup torque converter:
A torque converter fitted with a lockup clutch that can be engaged to eliminate the slip between the torque converter's input and output, thereby improving fuel efficiency and performance because it is now in direct drive mode
Lock-up torque converter:
Torque converter in which the pump can be mechanically locked to the turbine, eliminating any loss through the fluid because it is now in direct drive mode
Lockwasher:
There are several types of lockwashers which are designed to be placed between a
flat washer and the securing nut in order to keep the nut from backing out or
loosening. One type is a split ring. Another looks like a star with prongs or
tangs coming out from the outer circumference. Also called a "star washer." Another
type has prongs coming out of the inner circumference of the washer. Also See: helical spring lock washer spring lock washer
Locomobile:
A vehicle brand of which all models 48 and 90; 1927 8-80; 1928 8-80; and 1929 8-80 are classic cars.
Locut nut:
A fastener used to enable sheet metal screws to be used for relatively large holes in panels
A record book carried by truck drivers in which they enter their
hours of service and duty status for each 24-hour period. Required
in interstate commercial trucking by the U.S. Department of
Transportation.
Logic controller:
A part of the wheel slip brake control system which interprets input signals
from the sensor(s) and transmits the controlling output signals to the
modulator(s).
Log manifold:
A special intake manifold generally designed to accept four or more carburetors. Each side has bases for the carburetors set on a pipe-like log area.
A suspension system using an upper and lower control arm. The upper arm is shorter than the lower. This is done so as to allow the wheel to deflect in a vertical direction with a minimum change in camber.
A long block consists of the short block plus the oil pump and sump, cylinder head(s), camshaft(s) as well as the complete valve train. The opposite is short block
Long block engine:
An engine with a relatively long crankshaft. The opposite is short block engine. Also compare big-block engine. Normally, the term long block engine means a 6-cylinder in-line engine which has a longer block than a 4-cylinder or V-8 engine
Long Combination Vehicle:
(LCV) In general, vehicles longer than a standard doubles rig
(tractor and two 28-foot semitrailers). Examples of LCVs which are
permitted in some U.S. western states and eastern toll roads: Twin
48-foot trailers; triple 28-foot trailers.
Longeron:
The main side member
Long-haul:
A long distance which a trucker drives
Longitudinal:
Lengthways. The opposite is lateral
Longitudinal engine:
A traditional engine layout used on most RWD vehicles with the cylinders lying lengthways from the front to the back. Also called north-south layout. The opposite is transverse engine
The distance between the tread and the closest point forward or rearward, reduced by increase in tread depth and rearward movement of the axle under load (1/3 of the distance between shackle pin centers).
Longitudinal leaf spring:
A leaf spring that is mounted so that it is parallel to the length of the vehicle.
Longitudinals:
Fore-and-aft structural shape or plate members attached to the underside of decks, flats, or to the inner bottom, or on the inboard side of the shell plating.
Long-nose pliers:
Pliers with half round and tapered jaws, often with a wire cutter and used for electrical work. Also called snipe-nose pliers or needle-nose pliers
Long-nose self-grip pliers:
Locking pliers with extra long reach jaws
Long-reach C-clamp:
Self-grip locking clamp with extra long C-shaped jaws
Long stroke engine:
An engine where the length of the piston stroke is greater than the diameter of the bore of a cylinder. A relatively long stroke produces higher low-end torque at the cost of increased piston speeds and reduced revving ability. The opposite is short stroke engine
Long ton:
2240 pounds. Also called "gross ton."
Look compatible:
A type of bicycle shoe which has three holes drilled into the sole in a triangular pattern to fit Look clipless pedals.
A non-adhesive tape used as a harness wrap. Adhesive-type tapes, including electrical tapes, are not recommended for wrapping harnesses. Often a piece of shrink wrap is used at tape ends to keep the tape from unravelling
Early motorcycle frame design in which the downtube curves underneath the engine cases to become the seat post
Loop scavenging:
A method of scavenging used on two-stroke motorcycle engines. The entering gas streams travel across the piston, up the far side of the barrel and curl over and down to complete the scavenging process; loop scavenging is sometimes used to refer specifically to a special variant of this type of scavenging: Schnürle scavenging
The ventilation slots such as sometimes found in the hood of an automobile or in the dash. They let air come into the engine compartment to cool the engine or into the passenger compartment. Sometimes they are merely decorative with no cooling function. Also See: rear window louvres
(L) A driving gear ratio in automatic transmissions for climbing hills (to prevent lugging or for going down steep hills so that it acts as a compression brake. Also See: bull low four-wheel-drive low
Low-bake booth:
A closed section in painting lines in a paint shop, in which coats of paint are dried at low temperatures
Low-bake equipment:
Equipment for drying coats of paint at low temperatures
Low-bake paint:
Respray paint baked at 80°C, giving a high-quality finish but requiring suitable low-bake spray booths/ovens
Lowball:
A car sales practice of stating a very low price for a new car to a customer who is known or expected to be comparison shopping or calling over the phone. Compare highball. When the customer finds that other dealers cannot match this price, he will return to the original dealer, only to be told that the price was a mistake; many customers will then accept a new, higher price because they are tired of shopping around
Low battery:
A battery with less than acceptable voltage and should be charged or replaced.
Low beam:
The outboard headlights in a four-light system or the main lights in a two-light system. The low beam is used for most applications of night driving. For those cars without day-time running lights, the low beam should be turned on. In fog and heavy snow, the low beam can provide more light on the road because the high beam reflects light back to the driver. The British term is "dipped beam."
Low bed:
A low platform trailer for heavy equipment hauling, usually on 15" diameter tires. Also called low boy.
Low boy:
A low platform trailer for heavy equipment hauling, usually on
15" diameter tires. Also called
low bed.
An open flat-bed trailer with a deck height very low to the
ground, used to haul construction equipment or bulky or heavy
loads.
Low brake pedal:
A condition where the brake pedal approaches too close to the floorboard before actuating the brakes.
Low-carbon steel:
Steel containing 0.03 to 0.3 per cent carbon (typically 0.2%). Used for machine screws, wood screws, etc., and similar products without critical strength requirements. It cannot be heat treated for greater strength. Sometimes called "Mild Steel." The tensile strength is around 54M psi.
A curved block of cast iron for bending slight contours. It is used with a bumping
hammer to reshape slight contours. See dolly
Low crown panel:
The predominant shape of modem body panels, e.g., on most side panels such as
door skins. The opposite is high crown panel
See crown
Low-density polyethylene:
(LDPE) a relatively soft, flexible polyethylene, used mainly for plastic film and sheet
Low-drag caliper:
A calipere designed to reduce pad drag on the
rotor
Low-emission:
A condition of a vehicle which releases relatively few pollutants into the environment. Compare zero emission vehicle. In some countries tax relief is available for low-emission cars
Low Emission Vehicle Standards:
(LEV) State and federal governments set standards for automakers developing vehicles that will produce emission. Each state determines its own levels as does the federal government. California and New York have some of the most stringent laws. Once the requirements are met for a specific vehicle, the automaker may call that car or truck a Low Emission Vehicle. Also See: ultra Low Emission Vehicle Standards
A set of springs and other suspension parts to reduce ground clearance.
Lowers:
The bottom part of a motorcycle fairing to protect the rider's legs from wind and provide a more aerodynamic configuration
Low fuel indicator:
A warning light which glows when fuel is getting low and flashes (on some models) when it is very low.
Low gear:
The lowest gear in a transmission, usually called first gear.
Low geared:
A transmission which has a small drive gear and a large driven gear. On a bicycle, for instance, the chainwheel gear (by the pedals) is the smallest (usually called a granny gear and the freewheel gear (at the center of the wheel) is the largest. This arrangement gives the slowest speed but the best torque.
Low head pressure:
Lower-than-normal-high side pressure caused by a system malfunction
Low-head pump:
A pump used for low total heads; in the case of centrifugal pumps the low-pressure pump has a nominal total head not exceeding 80 m
Low-loader:
A truck for heavy loads with a low-level loading platform and often an extension ramp or lift-operated tailgate which can be lowered to street level
A condition where excessive clearance at some point in
braking system causes full pedal movement for application of brakes
The condition in which the brake pedal must travel very far or very
close to the floor
Low pivot swing axle:
A rear axle setup that attaches the differential housing to the frame via a pivot mount. A conventional type of housing and axle extend from the differential to one wheel. The other side of the differential is connected to the other driving wheel by a housing and axle that is pivoted at a point in line with the differential to frame pivot point.
Low-pressure control:
Cycling device connected to low-pressure side of system.
Low-pressure cut-out:
A device which protects the air conditioning system by switching the compressor off when a pressure loss occurs
Low-pressure cut-out switch:
A device that disengages the compressor clutch when the system pressure drops below a predetermined level
Low-pressure foaming:
A process in which plastics are foamed under low pressure (1-5 bar). The opposite is high-pressure foaming
Low-pressure gauge:
Instrument for measuring pressures in range of 0 psia to 50 psia 10 kPa to 350 kPa.
Low pressure indicator:
A unit or combination of units which provides a visible or audible warning signal whenever the system pressure is below a predetermined value.
Low-pressure pump:
A pump used for low total heads; in the case of centrifugal pumps the low-pressure pump has a nominal total head not exceeding 80 m
Low pressure safety cutout:
Motor protection device that senses low-side pressure. Control is wired in series with the motor and will shut off during periods of excessively low suction pressure.
Low pressure tire:
A tire with a large cross-section for operation at lower pressure. Increased air capacity permits lower pressure. ATV tires, for example, have only 3 or 4 psi.
Low profile:
A tire with a low aspect ratio of a tire (i.e., the section height is smaller than section width).
Low-profile air cleaner:
A circular, flat, chrome-plated air cleaner, mounted on top of the carburetor
Low-profile tire:
A tire with a wide tread but a low height. A tire with a height that is 70% or less of its width would be described as low-profile, as opposed to an average tire of 80%
Low-refrigerant protection system:
A system which interrupts the electrical current to the compressor clutch in the event of refrigerant loss. A typical exhaust is the GM superheat switch and thermal limiter low side: suction side -- the low pressure part of the system between the expansion valve outlet and the compressor inlet
Low rider:
A customized car which is extremely lowered through body and suspension modifications
Low side:
An air conditioning term describing the side between the expansion valve or orifice tube and the compressor; includes the evaporator -- called the low pressure portion
Another term for "suction side." The low pressure part of the system between the expansion valve outlet and the compressor inlet
That portion of a refrigerating system which is below evaporating pressure.
Low-side float flooded system:
Refrigerating system which has a low-side float refrigerant control.
Low-side float valve:
Refrigerant control valve operated by level of liquid refrigerant in low-pressure side of system.
Low side gauge:
A gauge that can indicate both pressure and vacuum. Also called a compound gauge
Low-side pressure:
Pressure in cooling side of refrigerating cycle.
Low-side pressure control:
Device used to keep low-side evaporating pressure from dropping below certain pressure.
A device, located on the suction or low side of the compressor, at which low side pressure can be checked and other service operations can be performed
Low speed:
Gearing provided in an automobile which causes greater number of revolutions of engine as compared to driving wheel
Low spot:
An indentation on a panel surface
Low-suction pressure:
Condition of lower than normal high side pressure caused by system malfunction
Low temperature activity:
A description of the ability of a catalytic converter to purify exhaust gases in the warm-up phase following a cold start. This phase is included in most of the current exhaust emission test procedures, as CO and HC concentrations are particularly high when engines are operated below normal operating temperatures
The wiring in the ignition system that is distinguished from the high tension wiring. The low tension leads carry only 6 or 12 volts. Includes the battery cables, the coil connections (but not the high tension wire going to the distributor), the wiring to the ignition switch, and the non-high tension wires going to the distributor.
A technology used in present-day phosphating processes. Normal zinc phosphating baths used as pre-treatment for painting contain approximately 2-4 grams-per-liter (g/l) zinc and approx. 5-10 grams-per-liter (g/l) phosphorus pentoxide. In low-zinc baths, the corresponding values amount to approx. 0.4-1.7 g/l zinc and 12-16 g/l phosphorus pentoxide
Lozenged:
A car chassis which, as the result of an accident, no longer holds its true shape but is rather pushed into the shape of a rhombus or diamond