DICTIONARY OF AUTOMOTIVE TERMS - "Hu"

Hub

1. On a Bicycle, the center of a wheel consisting of a shell to which Spokes attach and contains an axle along with two sets of bearings, bearing Cones, Lockwasher, Locknuts, and parts for attaching the wheel to the Frame.
2. The base of a wheel with studs protruding from its face upon which the wheel itself is mounted to an automotive vehicle.
3. A rotating component at the center of a wheel that contains the wheel bearings. It is attached to, or integral with, the brake drum or rotor.

Also See
Cassette Hub
Central locking hub
Freewheel hub
Freewheeling hub
Front Hub
Safety hub
Splined hub
Wheel hub

Hubbed drum

A brake drum mounted on a hub.

Hub brake

Any type of brake (Disc, Drum, or Coaster) that operates through the wheel hub rather than the rim.

Hubcap

The covering that fits over the end of the wheel Spindle to keep dust and water away from the wheel bearings and brakes. It is often a styling feature, but it also acts as a good container for keeping the Lug nuts from being lost when changing tires. When a vehicle becomes stuck in the snow, it can also be used as a temporary shovel. Also called wheel cover.

Also See
Moon

Hub cap

See
Hubcap

Hub carrier

1. A part of the suspension system which carries a rear wheel hub on a front-wheel drive vehicle, or on a rear-wheel drive vehicle with independent rear suspension.
2. Another term for Steering swivel

Hub cassette

See
Cassette hub

Hub-center steering

Steering system in which the wheel pivots about its center point; the axle is normally fixed

Hubcentric fit

A spigot mounted wheel

Hub flange

The portion of a bicycle hub into which the spokes are seated.

Hub freewheel

See
Freewheel hub

Hub height

In a horizontal-axis wind turbine, the distance from the turbine platform to the rotor shaft.

Hublock

In 4-wheel-drive vehicles, it is inefficient to have the front wheels connected when not needed. Most older vehicles required a person to get out and manually switch each front hub. Now these hubs can be changed remotely with a switch inside the vehicle.

Also See
Pulse vacuum hublock

Hubodometer

A register mounted on the axle hub which shows the distance the vehicle travelled. It is popular to record mileage for leasing of vehicles or tires particularly on trailers, since there is no other odometer present.

Hub plate

The central element of a clutch driven plate which carries the splined hub

Hub puller

A special tool, of both jaw and slide hammer design, used to remove wheel hubs on vehicles by a pulling action

Hub spacing

The distance from one outer cone to the other along the axle. Front bicycle hubs have a standard width of 100mm. Rear hubs on older road bikes which are set up for freewheels generally have a width of 126mm. More recent rear hubs set up for cassettes have a width of 130mm.

HUD

An acronym for Heads up display which is a system of mounting gauges so that the read-out is shown on the Windshield. In this way the Driver does not have to take his eyes off the road to see how his vehicle is performing.

Hudson

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Hudson

A brand of vehicle of which the 1929 Series L is a Classic car. All 1948-49 models are Milestone cars. The 1951-54 Hornet models are Milestone cars.

Hull

Body of a ship which floats on the water

Humber

A brand of vehicle of which the 1925-1948 models, with required application, are Classic cars.

Humidifiers

Device used to add to and control humidity.

Humidifying tower

The air saturator tower in salt spray test chambers

Humidistat

Electrical control which is operated by changing humidity.

Humidity

The moisture or dampness in the air. Usually refers to an uncomfortably high level of humidity.

Also See
Absolute humidity
Relative humidity

Humidity chamber

A test chamber for simulating tropical and subtropical conditions

Humidex

(short for humidity index) is a number which combines the air temperature in Celsius and the amount of humidity in order to give a single number to represent the perceived discomfort of weather that is hot and humid. It was devised by Canadian meteorologists and first used in 1965. The humidex is widely used in Canada and has been accepted in a number of other countries.

Range of humidex	Degree of comfort
Less than 29	No discomfort
30 to 39	Some discomfort
40 to 45	Great discomfort; avoid exertion
Above 45	Dangerous
Above 54	Heat stroke imminent

The humidex is calculated with the following formula
Humidex = (air temperature) + h
where
h = (0.5555)*(e - 10.0);
e = 6.11 * exp(5417.7530 * ((1/273.16) - (1/dewpoint)))

Hummer

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Hummer

A large SUV produced by General Motors which is based on the military High Mobility Multipurpose Wheeled Vehicle (HMMWV or Humvee). Models included are H1 (1993-2006), H2 (2003-07), H3 (2006-08), H3 Alpha (2008), and H3x (2008)

Hump

A raised portion on the rim bead seat of passenger car wheels, retaining the beads of an insufficiently inflated tubeless tire on the bead seats, thereby preventing the tire beads from jumping into the rim well.

Also See
Flat hump
Hump rim
Outboard flat hump
Outboard round hump
Round hump
Safety bead seat
Safety rim

Hump mode

An operating condition where the transmitted torque in a viscous coupling rises to a value several times higher than the value produced in the so-called Viscous mode, due to internal clamping, i.e., metal friction of the coupling discs

Hump rim

Designation for a rim featuring a safety contour (Round hump, Flat hump, combination hump) either on the outer or on both bead seats. This protection is particularly important with tubeless tires, where sudden deflation can occur if the tire beads leave the bead seats and drop into the well. Compare Hump and Safety bead seat

Hundredweight

(cwt) An obsolete unit of weight measurement, used in some classic-car manuals. 1 British cwt = 5080 grams; 1 US cwt = 4535 grams

Hunting

1. The uneven running of an engine, due to air/fuel mixture being too rich.
2. The action of some automatic transmissions when a vehicle is climbing a hill. The transmission constantly shifts between fifth gear and fourth gear

Hunting tooth

An extra, odd tooth on a gearwheel, designed to ensure the same teeth do not always mesh together, thus reducing wear

Hurst six-speed shifter

Upgraded shifter for manual transmissions which make the distance between gears shorter. The power band is more continuous from the bottom of first gear to the top of sixth. This means that when you shift, the amount of acceleration you experience will be more even throughout all the levels of the transmission. The result is that you can make the car accelerate faster and gain more control (through enhanced consistency) in turns or any application of power. Hurst also manufactures many other shifters with 2 to 6 gears for a variety of cars. Linda Vaughn has been their spokeswoman for many years.