Got Questions? Hendrickson Ride Solutions

Q. How does Hendrickson minimize maintenance on an air suspension system?

A. On an air suspension, the hydraulic shock absorber plays a crucial role in suspension damping, but it is also likely requiring replacement or service during the life of a trailer. With the development of ZERO MAINTENANCE DAMPING (ZMD) technology, Hendrickson set out to determine a way eliminate the shock, but not the damping and vehicle control that goes along with it.

After a few years of development testing in our research and development lab, Hendrickson dialed in an air spring design that could effectively replace the damping function of the shock. The patented ZMD air spring, which has an extended warranty period over a standard air spring, has no hydraulic fluid or internal moving parts. Instead, by using pressurized air, ZMD provides consistent damping over its lifetime, unlike a hydraulic shock absorber that loses damping capacity over time.

The idea of eliminating a service item like shocks is exciting for fleet service managers, especially as the availability of trained technicians continues to be a challenge in our industry. From a service standpoint, the investment in ZMD technology seems like an easy decision. It can pay dividends once the vehicle has been in service for a couple of years.

What we did not anticipate in our development work was the reaction we received from drivers. Upon launching the product, we nearly immediately got comments from drivers that the ZMD system provided significantly better ride over existing suspension designs. Further field trials corroborated the driver experience.

Similar to the way standard air ride suspensions achieve variable spring rates via pressure adjustment through by the height control valve, suspension damping is tailored to the load with ZMD air springs. By eliminating the shock absorber, which transmits forces to the trailer that can be felt by the driver, drivers report feeling less “back slap” or “kidney punch.”

The growth of air suspensions in the market over the years is largely due to their ability to reduce shock and vibrations transmitted to the trailer from the wheels and road. As driver and technician retention continue to be a problem, suspension solutions, like ZMD, that provide a better ride and reduce maintenance will become the key in modern suspension designs.

Hendrickson - ZMD - Zero Maintenance Damping (hendrickson-intl.com)