Cosworth Weight Jacker

One of the most historic races on the motorsport calendar, the Indianapolis 500, presents some unique challenges for drivers taking on the iconic oval track. Drivers will be seeking any advantage possible to win the coveted top spot at the Brickyard.

One of those margins to victory comes from the help of the weight jacker. Located on the right-rear damper, the weight jacker is a driver-activated tool that utilizes a hydraulic ram to manipulate the suspension and weight distribution of the car. When activated, the hydraulic ram is extended and pushes the spring away from the perch to raise and extend the right rear of the car. This creates a diagonal force which adds load on the front left tire, thus reducing understeer in turns.

“The weight jacker is a very secret and highly developed piece of active suspension that allows the drivers to adjust the handling characteristics to prepare for each turn. Each turn is different at the Indianapolis 500, so the focus and knowledge that is required to adjust the weight jacker is impressive.

The control behind this is all made possible by Cosworth’s steering wheel componentry, which captures the driver’s inputs, and is then processed by our intuitive software and finally sent to Cosworth’s Weight Jacker Controller, which commands the motor to increase or decrease hydraulic pressure to the weight jacker itself depending on driver input. It’s a simple yet very effective tool for the drivers on the ovals” explains Motorsport Regional Manager Ethan Duncan.

While the weight jacker is primarily used for improving the car’s handling in turns, on straights it proves to be less effective. To combat this, drivers have adapted to rapidly deactivate the weight jacker out of Turns 2 and 4 to improve straight-line speed.  By deactivating the weight jacker on the straights, the rear of the car is lowered, reducing downforce and improving straight line speed, giving drivers the ability to secure the best possible lap time.