Skip to content

Passive Shock Absorbers and Struts

Passive-Shock-Absorber-Strut-Damper-cutaway-image Compressed for Desktop
Passive-Strut-Damper-Shock-Absorber Compressed for Desktop


BWI Group passive dampers are derived from a century-long heritage of suspension technology development and manufacture carried out first by Delco Products Division of General Motors Corporation, later by Delphi Automotive, and now by BWI Group. Product portfolio ranges from dampers for all sizes of passenger cars through performance and luxury cars to heavy SUV’s and delivery vans.


BWI Group manufactures passive dampers for OEM market in Europe, Asia and North America, developing the core technology in one major technical center in Europe (Kracow, Poland) and working on applications in customer regions.

BWI Groups product development capabilities include:

  • Full CAE capability at vehicle/suspension/component level with FEA-based sizing of structural components and simulation of damper performance (fluid dynamics and valve mechanics)
  • Prototyping capability following manufacturing processes intended for serial production
  • Expertise in Vehicle Road Load Data analysis and definition of accelerated tests
  • Full range of validation testing to replicate vehicle operating conditions (labs and experimental vehicles)
  • Ride Development capability with ride vans and tuning personnel in all regions



BWI Group passive dampers technology is based on a Bill of Design (BoD) and Bill of Process (BoP) principle combined with continuous improvement and an innovative approach to new product functionalities.

BoD/BoP collects all proven technologies and lessons learned throughout years of manufacture into a set of standardized, reliable and economical design and process solutions.

BWI Group delivers the whole range of passive damper design variants: shock absorbers, coil-over-shock absorbers and McPherson struts in twin- and monotube execution. Piston rod size for twintube dampers ranges from 10 to 28 mm, while main valve sizes extend from 20 to 40 mm. For monotube dampers, piston rod sizes range from 11 mm to 18 mm combined with 36 mm or 46 mm valves. Standard solutions may also incorporate rebound energy management devices like steel or plastic rebound springs and bumpers.

BWI Group focuses on refining damper performance in terms of NVH behaviour and friction reduction. As a result, BoD is regularly updated with noise-reducing features and low friction solution.








BWI dampers are appreciated by vehicle manufacturers for:

  • Wide tuning range to ensure superb ride, handling and comfort thanks to several families of highly tunable, durable and versatile valve systems;
  • Robust packaging ensured by a wide range of piston rod and main valve sizes together with vehicle-customized envelope and attachments;
  • Durability to address most demanding customer requirements;
  • Repeatability of damper performance in serial production due to use of precision components as well as optimized valve assembly process.
  • High quality of the final product due to highly automated and statistically controlled manufacturing and assembly processes.












Apart from standard passive damper technology, BWI Group offers innovative solutions to address or exceed evolving market expectations:

  • Weight reduction by means of:
    • Lightweight materials (composites, aluminum)
    • Tailored component shape and properties (hollow rod, variable wall thickness for outer tube, one piece clevis bracket)
    • Damper downsizing (monotube with base valve to achieve twintube performance in smaller monotube package)
  • Special hydraulic functions
    • End of rebound stroke energy management system (Hydraulic Rebound Stop, or HRS)
    • End of compression stroke energy management system (Hydraulic Compression Stop, or HCS)
    • Special valves (SuperProgressive, SuperDigressive)
Monotube damper with additional compression valve

Monotube damper with additional compression valve between piston and gas cup...

Read More
One piece knuckle bracket

Conventional strut clevis bracket design assumes an insert and outer shell, resistance welded together. The optimized shape consists of a reinforced insert....

Read More
Lightweight Materials

A direct way to reduce weight is to replace currently used materials (all grades of steel) with lightweight equivalents like...

Read More
Tailored component shapes and properties

A direct way to reduce weight is to replace currently used materials (all grades of steel)...

Read More
Hydraulic Rebound Stop (HRS) for end of rebound stroke energy management

The aim of the Hydraulic Rebound Stop is to improve...

Read More

Design aimed at reduction of maximum force transmitted to vehicle body in compression stroke and improvement of vehicle comfort...

Read More
Reservoir tube with variable wall thickness

Strut applications are exposed to significant level of bending moments which are....

Read More
Hydraulic Compression Stop (HCS) for end of compression stroke energy management

Hydraulic Compression Stop is an hydraulic system which replaces....

Read More

Design ensures steep increase of damping forces in compression stroke for piston rod velocities exceeding 1,5 m/s...

Read More
share via email
Visit Us
Scroll To Top