What the heck are Nivomat Shocks?
The Nivomat Shock Absorber is a self-leveling monotube shock absorber developed by Sachs. Nivomat is a contraction of two French words, niveau and automatique. When translated to English, it would be level automatic or automatic level.
Nivomat shocks are used by Chrysler, Ford, General Motors, Jaguar, Kia, Mitsubishi, Saab, Volvo and other OEMs. The system is also available on the GM Suburban and Tahoe as part of ZW7 Premium Smooth Ride Suspension. Replacement units are available from Monroe, ZF Sachs and OES suppliers.
The system makes use of the mechanical energy which is generated during the first meters of driving from the relative movement between the axle and vehicle body.
An unlevel vehicle can create many problems. Extra weight on the rear axle shifts the center of gravity, which has a major impact on the ride characteristics. In critical situations, the vehicle can be very difficult to control. Under these conditions a “floaty” ride characteristic can not be considered as comfort anymore.
Other effects are increasing expenses: The tires wear unevenly and faster. Bad aerodynamics causes a higher fuel consumption. Greater strain is also placed on the axle as a whole.
In place of conventional shock absorbers, this unique system is installed on the rear axle. While providing additional roll stability without requiring any additional electronics, the Nivomat adjusts the vehicle to the optimum ride height for every load condition, thus ensuring a safe and comfortable ride.
The Nivomat system does more than just level the vehicle under load. As the load increases, the pressure inside the shock increases as oil is displaced from the reservoir to the inside of the unit, compressing the gas volume. This creates a progressive increase in spring rate and damping with little or no change to ride frequency.
The Nivomat is like an ordinary monotube shock absorber with a hydraulic piston, tube and accumulator. There are two different configurations of the shock. The first looks like a conventional twin tube air shock with a dust cover. What appears as a dust cover houses the high pressure accumulator and low pressure oil reservoir.
The second configuration has its high pressure accumulator at the top of the shock. This reduces the overall diameter of the shock. This allows the shock to be installed in a more confining space, such as an independent rear wheel drive suspension and can be mounted in a shaft up or down configuration as designed by the manufacturer. The normal application for this shock absorber is for the rear suspension of a passenger car or SUV.
What gives the shock its leveling capability is a pump mechanism and oil reservoir that can increase the accumulator pressure, which increases the shocks lifting capability. It is used in combination with springs matched to the load capacity of the shock to reduce suspension travel while utilizing more of the piston and shaft travel of the shock.
This maintains the ride quality whether the vehicle is operated with a driver only or to compensate for passengers and luggage. The big advantage to the Nivomat is the shock absorber requires no plumbing, compressor and height sensing device to level the vehicle. The normal movement of the suspension over a regular road surface provides enough pumping action to level the vehicle.