Car suspension

An early form of suspension on ox-drawn carts had the platform swing on iron chains attached to the wheeled frame of the carriage.

Horse-drawn carriages and Ford Model T used this system, and it is still used today in larger vehicles, mainly mounted in the rear suspension.

[citation needed] Henry Ford's Model T used a torque tube to restrain this force, for his differential was attached to the chassis by a lateral leaf spring and two narrow rods.

The torque tube surrounded the true driveshaft and exerted the force to its ball joint at the extreme rear of the transmission, which was attached to the engine.

A similar method like this was used in the late 1930s by Buick and by Hudson's bathtub car in 1948, which used helical springs that could not take fore-and-aft thrust.

Also, the dynamic defects of this design were suppressed by the enormous weight of U.S. passenger vehicles before the implementation of the Corporate Average Fuel Economy (CAFE) standard.

[citation needed] Rear-wheel drive vehicles today frequently use a fairly complex fully-independent, multi-link suspension to locate the rear wheels securely, while providing decent ride quality.

Riding in an empty truck meant for carrying loads can be uncomfortable for passengers, because of its high spring rate relative to the weight of the vehicle.

[citation needed] By 2021, some vehicles were offering dynamic roll control with ride-height adjustable air suspension and adaptive dampers.

[9] Roll couple percentage is a simplified method of describing lateral load transfer distribution front to rear, and subsequently handling balance.

A desert race vehicle, which must routinely absorb far higher impact forces, might be provided with pneumatic or hydro-pneumatic bump-stops.

These are essentially miniature shock absorbers (dampers) that are fixed to the vehicle in a location, such, that the suspension will contact the end of the piston when it nears the upward travel limit.

The instant center for any wheel package can be found by following imaginary lines drawn through suspension links to their intersection point.

Theoretically, if the resultant of the vertical load on the tire and the lateral force generated by it points directly into the instant center, the suspension links will not move.

Then, multiply the tangent by the front wheel braking effort percentage and divide by the ratio of the center of gravity height to the wheelbase.

But at high frequencies caused by road surface roughness, the parts isolated by rubber bushings act as a multi-stage filter to suppress noise and vibration better than can be done with only tires and springs.

It is generally accepted, that MacPherson struts are the most compact arrangement for front-engined vehicles, where space between the wheels is required to place the engine.

A number of different types of each have been used: Traditional springs and dampers are referred to as passive suspensions — most vehicles are suspended in this manner.

For example, a hydropneumatic Citroën will "know" how far off the ground the car is supposed to be, and constantly resets to achieve that level, regardless of load.

[17] Delphi currently sells shock absorbers filled with a magneto-rheological fluid, whose viscosity can be changed electromagnetically — thereby giving variable control without switching valves, which is faster and thus more effective.

Nissan introduced low-bandwidth active suspension circa 1990 as an option that added an extra 20% to the price of luxury models.

A fully active system from Bose Corporation, announced in 2009, uses linear electric motors[18][19][20][21][22] in place of hydraulic or pneumatic actuators that have generally been used up until recently.

Later developments by the Catalan company Creuat have devised a simpler system design based on single-acting cylinders.

The system was changed in favour of coil springs over dampers due to cost reasons towards the end of the vehicle's life.

But vehicles with more than two wheels, and equipped with a conventional suspension system, could not do the same until now, so the passengers feel the outward inertial force, which reduces the stability of riders and their comfort as well.

If the road does not have super-elevation or banking, it will not affect the comfort with this suspension system, the vehicle tilt and decrease in the height of the center of gravity with an increase in stability.

By World War II, the other common type was torsion bar suspension, getting spring force from twisting bars inside the hull — this sometimes had less travel than the Christie type, but was significantly more compact, allowing more space inside the hull, with the consequent possibility to install larger turret rings, and thus, heavier main armament.

Torsion bars may take space under or near the floor, which may interfere with making the tank low to reduce exposure.

As with cars, wheel travel and spring rate affect the bumpiness of ride, and the speed at which rough terrain can be negotiated.

This apparently made a significant contribution to speed, range and track life, as well as providing a continuous band of protection.