Abstract: A seat suspension system includes a seat frame movably supported on a base in a fore and aft direction by guide rollers supported on the base and received into rails on the seat frame. A seat attenuating device supported on seat frame includes a rod rotatably supported on spaced brackets and having a lug extending rotatably therefrom between the supports with first and second coil springs telescoped over the rod and located between the lug and the respective supports. An accumulator is connected at one end to a rod and at the opposite end to one of the brackets, while a plate is supported on the base and has notches for receiving at least a portion of the lug to define a plurality of adjusted positions for the seat frame on the base. A lock-out member cooperates with the lug on the rod and is supported on the seat frame to fix the seat frame with respect to the base when desired.