The BMW 5 Series has been setting the standard for many decades in the upper midsize class. Few other model series from a German car manufacturer combine sportiness and travel comfort as skillfully in each model generation as the BMW 5 Series, which has been offered since 1972.
For the BMW 5 Series Touring (G31, station wagon) with its rear axle air suspension, we are introducing a new KW coilover suspension kit. The difference compared to our KW coilover suspension kits for older BMW 5 Series Touring models (E39, E61) with leveling control with air springs on the rear axle is that we have specially developed the rear axle damper, adjustable in compression and rebound for use with the stock air spring 1972.
The KW stainless steel shock absorber struts are shorter than the OEM components and have been adapted for rebound travel for the stock air suspension. The original air springs are mounted on the rear axle dampers during the suspension installation.
The KW V3 coilover suspension for the BMW 5 Series Touring (G31) includes the necessary installation tools, and during damper production, the dampers are equipped with special elastomer spring elements. Those elastomer elements are much more like ordinary bump stops.
For the front axle strut assemblies, we stick with the traditional approach. We were able to draw on the development of our suspension for the BMW 5 Series sedan (G30). Only the spring rate, suspension travel, and damper configuration have been adapted to the specific requirements of the 5 Series Touring for the front MacPherson strut assembly.
While the stepless lowering is regulated via the trapezoidal thread on the strut, the original air spring on the KW rear damper sits lower than on the stock damper. In addition, an adjustable rear axle height sensor is used to set the desired depth. According to the parts certificate, the tested lowering range at both axles is between 30 and 55 millimeters.
To adjust lowering, the wheels should always be unloaded, to change the height at the front axle, it is recommended to first clean the threads below the trapezoidal spring perch with an old plastic brush, such as an old toothbrush.
Then, turn the perch downward and clean the trapezoidal thread above the old position. Now, the height can be adjusted individually. Afterward, please measure and adjust the alignment and the lighting to the new lowering or height. In the case of the 5 Series Touring (G31) with the rear axle tie rod, the height is adjusted to the millimeter.
The dampers can also be adjusted manually separately in the parameters of compression and rebound damping, allowing you to fine-tune the recommended setup to your driving experience regarding handling and comfort.
This works similarly to the optional BMW M Performance suspensions that we have developed in collaboration with BMW M and manufacture here at our facility in Fichtenberg. The preset setup of the KW V3 coilover suspension for the BMW 5 Series Touring (G31) is always designed to be as firm as necessary and as comfortable as possible.
The pre-dialed damper setup of the KW V3 coilover suspension kits with its adjustable low-speed compression and low-speed rebound valves for the BMW 5 Series Touring is set to provide the best compromise between ride comfort and dynamic handling, as validated by our colleagues in the development department and during testing.
With 16 clicks, the cross-section (of the low-speed rebound valve can be reduced or enlarged. Opening the rebound valve noticeably increases comfort. Closing the rebound valve reduces body roll and pitch movements. The BMW handling becomes even more dynamic than in the stock configuration.
Additionally, the adjustable low-speed compression can close or open with twelve clicks, allowing you to have more influence on steering behavior and tire grip level. In simple terms, the task of rebound is to connect the chassis to the road, while compression influences the suspension’s compression and supports the body structure.
The high-speed valves responsible for ride comfort on rough roads or severe bumps for both compression and rebound ensure that the BMW 5 Series Touring achieves a surprising level of ride comfort, even with maximum chassis drop (lowering) and low-profile tires.
The KW V3 coilover suspensions for the BMW 5 Series (G31) Touring with BMW xDrive (all-wheel drive) are still in preparation and development.