Dual ball joints, five links and a limited-slip diff

Cadillac ATS / Overview / Dual ball joints, five links and a limited-slip diff

Up front, a multi-link double-pivot suspension - based on the MacPherson strut design - is used for a more precise feeling of control, including more linear and communicative steering, and a smoother ride. It also improves impact isolation on bumps and rough surfaces.

The double-pivot system incorporates a pair of ball joints and lower control arms - one in tension and the other in compression - to replace a conventional wishbone at each wheel. The control arms, the spindle and the body form an effective four-bar link for each side of the front suspension, creating virtual pivot points for greater camber control. There is also a direct-acting stabilizer bar.

The front suspension's design also enables a longer spindle, larger pivot center and positive-offset steering geometry for optimal steering control, excellent straight-line stability and a more refined ride. High-durometer rubber and hydraulic bushings are used with the front suspension for an excellent balance of ride comfort and precise response when corning.

"The kinematics of the ATS's front suspension are more complicated, but the payoff is worth it in the way the car drives," said Berube. "The driver will feel directly connected to what the front wheels are doing, but with a comfortable degree of isolation that makes the Cadillac ATS a great touring car for long drives."

At the rear of the ATS is the first five-link independent suspension in a Cadillac. It's a design that helps reduces roll center motion, enables positive lateral control, reduces "squat" during acceleration and promotes excellent dynamic stability. In short, it helps keep the tires planted on all surfaces and during all hard-cornering maneuvers.

Four handling links (upper and lower control arms) are used at each side to control wheel motion and a toe link at each wheel provides additional horizontal control - particularly during hard cornering. The upper and lower links create an effective double-wishbone design, although the links are mounted independently.

As with the front suspension, the five-link design creates virtual pivot points that the ATS's engineers used for geometry optimization. The stiff links are mounted on a cradle that contributes to a smoother, quieter and more isolated ride. The cradle is made of steel (with hydroformed side rails) to help optimize the car's structural stiffness and mass.

"Using an aluminum cradle would have reduced the ATS's overall weight, but we found a few extra pounds at the rear suspension helped get the front/rear weight balance closer to the optimal 50-50 ratio," said David Masch, ATS chief engineer. "We also added mass to other areas of the car where it was necessary to achieve performance."

Seventeen-inch (17x8-inch) wheels used with 225/40-series tires are standard and 18x8-inch wheels and 255/35-series rubber are offered on the Cadillac ATS, with run-flat tires. Models with the FE3 suspension feature 18x9-inch rear wheels.

A mechanical limited-slip differential is a feature not matched by all other competitors and gives the ATS an edge when it comes to ensuring all of the powertrain's torque is applied to the tires during hard cornering. It is standard with the six-speed manual transmission and included with the FE3 sport suspension package. It is housed in a robust 8.6-inch carrier. Other models feature a 7.67-inch carrier.

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