All bypass shocks can be customized as far a tube placement. Tube length and placement are considered "zones". The length of the tube is based upon how long you want the piston to be "bypassed". The piston oil flow is always in play, but allowing some on the oil on compression and or rebound to go through these one way check valves instead of forcing all of the oil through the piston alone. By opening or closing the check valve dictates said bypassed flow. The shorter the tube, the smaller the effected "zone" is. Internal bypass shocks use a very similar setup, but you have to go inside the shock to make adjustments to the bypass ports. Either by changing the port size of changing the reeds that cover said ports. Once you get past the bypass ports, all of the oil is forced through the piston alone. The shock reservoir contains nitrogen and a IFP (internal floating piston). It is there so separate the high pressure nitrogen from the oil. Its main purpose is to help prevent cavitation by keeping pressure on the oil for the rebound stroke of the shock. The shock piston and the reservoir piston are completely different. The shock piston has controls oil flow via design and the shim stack. Where as the resi piston is basically a cap with seals that allow no oil or nitrogen to flow through it. In certain areas of the stroke, the bypass pistons work, once the piston passes that shock, it out of play (for a lack of better term). The slower that shaft movement, the easier oil flows through the piston, valve stack and bypass tubes/check valve. Okay, I've confused myself enough. Hopefully my jibber jabber helps you understand slightly better. :ez:
