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JRZ Suspension Engineering - 60 years of experience in development and research

JRZ HEAVY-DUTY vehicles dampers

Comfort, Handling, Heavy Duty

Comfort, Handling, Heavy Duty

JRZ Struts and Dampers have been used in a wide variety of heavy-duty vehicles all over the world for over 10 years.

The spring / damper units have been developed by Erik Ras to operate under the most difficult conditions and extreme terrain while maintaining perfect handling at speeds for vehicles with added weight.


  • Large fluid displacement because of the use of a 22 mm diameter pistonrod
  • Lifting force of damper created by using high nitrogen pressure
  • Compression damping with unique adjustable valving system in canister
  • Large 44 mm piston, with a large diameter non preloaded deflective disc valve
  • High flow return valve for quick refilling of working cylinder
  • Gas volume is selected in a way that the fluctuating gas volume and the temperature have little effect in the increase of pressure


  • Large piston diameter for good rebound control because of large fluid displacement.
  • Unique orifice rebound adjustment system

This results in:

  • Better handling conditions
  • Less tyre wear
  • More traction
  • Better comfort level
  • Better stability of the vehicle body
  • Increased lifetime of shock absorber


The gas pressure creates a lifting force. Because the piston rod diameter is 22 mm, the lifting force created is 3,8 kg/bar nitrogen pressure. Using 20 bar nitrogen pressure gives the damper a lifting force of 76 kg per corner. This lifting force works over the complete stroke, without adding spring rate to the system.

  • Added lifting force must not be confused as spring rate, a better comparison would be adding preload to the spring.
  • This lifting force works over the complete stroke.
  • A softer spring rate could be chosen, as the lifting force helps carrying the weight of the vehicle, resulting in lower natural frequency.
  • The lower natural frequency means better control of the sprung mass, so better handling and traction.
  • The gas pressure helps the tires contact patch with the road, providing better traction and grip.

Multi Pitch, Close Shoulder, Heavy Duty

Multi Pitch, Close Shoulder, Heavy Duty

JRZ’s expertise with vehicle dynamics in professional racing has been applied to develop suspension solutions for HEAVY-DUTY vehicles which are being used under extreme conditions. As the tire is another important part of the suspension, JRZ started the cooperation with Maxxis tires to develop a perfect solution for the HEAVY-DUTY vehicle market.


  • Premium highway terrain tire speciallty designed for armored cars up to 7200 KG total weight.
  • The first and only 12PR tire in this HEAVY-DUTY car business and with an even more comfortable ride experience. 128Q (1800KG by 160KM/h or 3968 pounds by 100 mile/h).
  • Dual speed load index 128/125Q (1800 KG by 160 kmpu) and 129/126N (1850 by 140 kmpu)
  • Three peak snowflake approved.
  • JRZ/Maxxis engineered a special carcass tread structure to create a wider foot print by heavy braking and impacts. This results in an up to 35% shorter braking distance at 80 km/h till full stop.
  • JRZ/Maxxis also specially improved the bead seat area and side wall design for these armored vehicles up till 7200 KG total car weight.This results in an incredible corner stability, increased stability by heavy crosswinds and straight line stability.
  • Ripple sipe design improves overall wear pattern and traction on slippery surfaces.
  • Self-cleaning pattern design which decrease tread puncture’s in off-road circumstances.


The high-volume circumferential grooves increase water dispersion efficiency for improved hydroplaning resistance.


This technology works in a way similar to noise-canceling headphones. The shoulder blocks are designed to produce sounds that dampen annoying pattern noise so the cabin stays quiet and serene.


The closed shoulder design limits noise resonance in the tread area which further improves the overall driving experience.

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