What Is a Seven Post Driver?

A vehicle's suspension is intended to provide a smooth method of transportation for its occupants. In the racing world, the suspension is key to victory. Engineers conduct extensive test on the chassis and suspension to improve overall performance.

  1. History

    • The predecessor to the seven-post shaker is the four-post shaker, which is non-effective for racing cars. The four-post shaker used by auto manufacturers to test their models for squeaks, rattles and durability has little use in testing a race car, other than for durability. By adding more posts to the system, the vehicle can be tested for lateral load, vertical load, squat and dive, etc. by controlling every movement between the chassis and suspension.

    Significance

    • Suspension testing plays a vital role in improving comfort and performance.

      A suspension is tested best in a controlled environment that simulates real-world conditions. Engineers easily can manipulate the conditions to gear the test to specific vehicles without building separate and/or multiple testing tracks.

    Expert Insight

    • Auto Research Center (ARC) has one of the most advanced seven-post shaker systems in the world. Henri Kowalczyk, ARC's vehicle dynamics manager, explains that everything simulated, that is "banking, lateral load transfer, braking and acceleration, and downforce ends up changing the vertical load of the tires, so that is ultimately what we are looking at."