Abstract: Apparatus and methods for providing a biasing force to a vehicle suspension. The apparatus includes a hydraulic shock absorber that coacts with a gas spring. In some embodiments, the gas spring is externally adjustable with regards to gas pressure, and also with regards to the amount of internal travel possible by a floating gas piston.

Abstract: An electronically adjustable shock absorber, and a system, method, and algorithm for developing a vehicle suspension. The shock absorber has damping characteristics that can be adjusted electronically to match a desired set of damping characteristics. The test method includes closed loop control of the electronically adjustable shock to achieve user-provided damping characteristics. The characteristics can be selected from a graphical user interface to simulate different internal flow passages of a shock absorber. Some embodiments make possible the simulated testing of different hardware embodiments, without the need to make the actual shock absorbers and without the need interrupt the vehicle suspension testing for multiple shock absorber installations.