Sleeper cab system lessens cab roll, sway

International Truck and Engine Corp has relocated the cab suspension system outboard to deliver improved comfort and stability. The new rear air bag cab-suspension system being installed on its International 9000 Series sleeper cabs helps give drivers better control and comfort — and their driving partners a more peaceful slumber — by reducing cab roll and sway.

The suspension system supports the weight of the truck and provides a more comfortable ride. Its components include front-and-rear suspensions, springs, shock absorbers, torsion bars, axles, a strut system, and connecting linkages. Changes that make driving less work and more enjoyable include:

• Locating the air bags and shock absorbers farther apart and outboard nearer the edge of the truck. This provides more stability, especially in crosswinds, by limiting pitch and yaw.

• Boosting the number of bumpers to two, to help with the yaw and provide more resting surface for the cabs when they're stacked to reduce damage from bumps.

• Placing a cup around the bumpers to give them greater load characteristics, which allows them to flatten less than previously, limiting the sway of the cab.

• Centering the bumpers over the mating stop to allow the full face of the bumper to contact the stop.

Because a sleeper cab is longer, more surface area on its sides becomes exposed to the wind. When crosswinds develop, drivers and anyone in the sleeper feels the roll and swaying. But with the shock absorbers and air bags farther apart, the ride becomes smoother and more stable.