Penske Shock Info

The rebound adjuster on the Spec Racer Ford shock absorber is located in the eyelet at the base of the main shaft.  Inside the window is an adjustment screw which serves as the control point for rebound adjustments.

During the rebound (extension) stage of the shock movement, fluid is forced through two ports in the main shaft. Inside the main shaft is a needle and jet assembly which adjusts the amount of fluid passing through the jet. By turning in the rebound adjuster (clockwise), the needle is forced up into the jet, restricting the fluid, causing firmer rebound damping forces. In reverse, by turning the adjuster out (counter clock-wise), more oil is allowed to pass through the jet causing lighter rebound damping forces. This rebound adjustment assembly, is in fact a timed control for the rebound shims located on the main piston to work. The flow is checked in the compression direction via a ball and seat valve.

The rebound adjuster has three full turns of adjustment or (18) flats. From the full hard setting, count out (18) flats to the full soft setting. The majority of adjustment is in the first (12) flats of adjustment from the full hard position.

From the full hard setting, there are (3) full turns of adjustment (18 flats) out to the full soft setting.

STARTING SET-UP -- Per Penske
Start at 12 flats from full hard and add one or two flats of rebound adjustment at a time. Continue this process until the car becomes “skittish” or the rear wheels hop under braking. At this point you know you have gone too far on the rebound settings, back off one flat. Once again, this is a basic procedure for finding your initial set-up for a given track.

Barry