Suspension
The hydropneumatic self-leveling suspension (featuring grapefruit-sized metal spheres containing nitrogen, acting as both springs and shock absorbers) gained a very sophisticated electronic control system called Hydractive, which used sensors in the steering, brakes, suspension, throttle pedal and transmission to feed information on the car's speed, acceleration, and road conditions to on-board computers. Where appropriate – and within milliseconds – these computers switched an extra suspension sphere in or out of circuit, to allow the car a smooth supple ride in normal circumstances, or greater roll resistance for better handling in corners.
The Hydractive system was somewhat "ahead of the curve" when the car was launched and early versions were sometimes unreliable. Many problems stemmed from the sensitive electronics controlling the car's hydraulic system, often caused by the poor quality of the multipoint grounding blocks — one on each front inner wing, one at the rear, and one under the dashboard. These tended to corrode (especially the ones in the engine compartment), causing all manner of intermittent faults which were hard to diagnose. On later cars, these were changed to screw terminals bolted through the bodywork, and most of the older cars have been modified in a similar way.
When the Hydractive system worked, the result was a big car with a smooth "magic carpet" ride, and better handling than many smaller, lighter, sports cars. When it didn't work, it was quite harsh and bumpy, although no worse than any contemporary high-performance sports sedan. However, right-hand drive XMs were never fitted with the DIRAVI variable fully powered steering of the CX, having an almost conventional DIRASS power-assisted setup.
Some production models of the XM were not equipped with the Hydractive system, but had a 'conventional' hydropneumatic suspension closer to that of the Citroën BX. These lower specification vehicles were all built for markets in mainland Europe.
Read more about this topic: Citroën XM
Famous quotes containing the word suspension:
“If the oarsmen of a fast-moving ship suddenly cease to row, the suspension of the driving force of the oars doesn’t prevent the vessel from continuing to move on its course. And with a speech it is much the same. After he has finished reciting the document, the speaker will still be able to maintain the same tone without a break, borrowing its momentum and impulse from the passage he has just read out.”
—Marcus Tullius Cicero (106–43 B.C)
“That willing suspension of disbelief for the moment, which constitutes poetic faith.”
—Samuel Taylor Coleridge (1772–1834)
“Leonid Ivanovich Shigaev is dead.... The suspension dots, customary in Russian obituaries, must represent the footprints of words that have departed on tiptoe, in reverent single file, leaving their tracks on the marble....”
—Vladimir Nabokov (1899–1977)