- Height adjustable suspension
Height adjustable suspension is a feature of certain
automobile suspension (vehicle) systems that allow the motorist to vary theride height or ground clearance. Such a feature requires fairly sophisticatedengineering .Height adjustment is most often achieved by air or oil compression used for the "springs" of the vehicle - when the pressure is varied - the vehicle body rises or lowers.
Factory systems
The first instance of a production vehicle with adjustable suspension was on the 1954 Citroën 15CVH. This vehicled featured a self-leveling, height adjustable
hydropneumatic suspension . Since this time, these systems have appeared continuously onCitroën models, including the DS and CX.Height adjustable suspension was banned in the
United States from 1974 to 1981, due to the stringent interpretation of passenger vehicle bumper height regulations by the U.S. government agency NHTSA.Many Modern
SUV s use height-adjustability as part ofactive suspension systems to improve the vehicle's versatility on and off road. The Range Rover offered this feature from 1993. New models of theFord Expedition have a computer-controlled system designed for convenience, which lowers automatically when the doors are unlocked by remote, returns to normal height when the vehicle is started, and (on 4-wheel-drive models), raises when the 4x4 system is engaged.Some sports cars use these systems to improve the vehicle's handling by lowering the vehicle's height during higher speeds - a current example being the
Mercedes-Benz Active Body Control system.Height adjustable
air suspension s are also equipped "Low-floor"city bus es mainly. This mechanism uses forbarrier-free :lowering floor at bus stop, to allow handicap passengers to board easily. Iron ring can be used for increase rear height.Aftermarket systems
Adjustable suspensions have become intrinsically associated with
lowrider vehicles. The popular image of these vehicles is of one "hopping" on its suspension, or sitting with one wheel completely off the ground.These systems were initially adapted from the
hydraulic pistons, valves and pumps used to adjust the flaps onaircraft . Today however, many aftermarket companies produce parts and equipment specifically designed forlowriders In recent years "air bag" systems (not to be confused with the
air bag safety device) have been rapidly gaining popularity among car customizers. Theseair suspension systems use heavy duty custom rubber "bags" to replace the stock shocks and springs, with either a compressor or tank of compressed gas used to raise and lower the vehicle at will.History of aftermarket systems
Ron Aguirre is commonly accepted as the first person to create a custom car with hydraulically adjustable suspension. In 1959 he scavenged the Pesco pumps and valves from a
B-52 Bomber and adapted them to the front suspension of his X-Sonic bubble-topped customCorvette , allowing him to change the height of the car with a switch on the dashboard.User control
Traditional height adjustable suspension is controlled by the driver manually.Certain modern layouts allow electronics alone to make this decision without the driver's control, especially if the car lowers at high speed.
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