The Variable Bleed Piston from Penske Racing Shocks offers the user more versatility than any other piston in our range. The piston can produce curves like those found on linear, digressive and VDP pistons and offers a very flexible way of controlling bleed. The piston makes use of six small bleed jets (three on each side of the piston), which are easily installed or removed using a 5/64” hex drive. The jets themselves are drilled through to give the desired amount of bleed – anywhere from a zero bleed to Ø.078”. Leaving the jet out completely gives a Ø.092” bleed orifice. The piston can make use of up to two separate shim stacks on each side. The inner (linear) stack uses a Ø1.350” base shim which unlike the VDP base shims, completely covers the ports. However the bleed jets, being recessed, are not covered by the base shims and are free to bleed past the inner stack. The outer (digressive) stack uses a Ø1.475” base shim and will offer a restriction to the bleed coming through the jets.