An air spring with a linearized spring rate comprising: a hollow spring piston having a spring hole through it; a hollow spring shaft having a spring shaft interior volume in communication with said spring hole in said hollow spring piston; and a spring body having a spring body interior volume in communication with said spring hole in said spring hollow piston; said spring hole in said hollow spring piston is in direct communication with the spring shaft interior volume and with the spring body interior volume providing a total spring interior volume; a body cap having: a first port being adapted for pressurizing and depressurizing said total interior volume of said air spring; wherein said total spring interior volume being greater than said spring body interior volume thereby providing a linearized spring rate; a cavity in the area on the non-pressurized side of the spring piston seal; and a vent; whereby, said vent being adapted to allow atmospheric air to enter said cavity thereby preventing a vacuum to be created when the air spring compresses, and being adapted to allow drawn in air to evacuate when the air spring retracts characterized by the body cap further having: a second port, said second port being adapted to either be: plugged whereby when said total interior volume being pressurized, said air spring acting as a closed system thereby providing a constant load carrying capability and spring rate; or attached to plumbing for a ride height/spring rate adjustable system, whereby said ride height/spring rate adjustable system pressurizes or depressurizes the air spring while on a vehicle. a hollow spring piston having a spring hole through it; a hollow spring shaft having a spring shaft interior volume in communication with said spring hole in said hollow spring piston; and a spring body having a spring body interior volume in communication with said spring hole in said spring hollow piston; said spring hole in said hollow spring piston is in direct communication with the spring shaft interior volume and with the spring body interior volume providing a total spring interior volume; a body cap having: a first port being adapted for pressurizing and depressurizing said total interior volume of said air spring; wherein said total spring interior volume being greater than said spring body interior volume thereby providing a linearized spring rate; a cavity in the area on the non-pressurized side of the spring piston seal; and a vent; whereby, said vent being adapted to allow atmospheric air to enter said cavity thereby preventing a vacuum to be created when the air spring compresses, and being adapted to allow drawn in air to evacuate when the air spring retracts characterized by the body cap further having: a second port, said second port being adapted to either be: plugged whereby when said total interior volume being pressurized, said air spring acting as a closed system thereby providing a constant load carrying capability and spring rate; or attached to plumbing for a ride height/spring rate adjustable system, whereby said ride height/spring rate adjustable system pressurizes or depressurizes the air spring while on a vehicle. plugged whereby when said total interior volume being pressurized, said air spring acting as a closed system thereby providing a constant load carrying capability and spring rate; or attached to plumbing for a ride height/spring rate adjustable system, whereby said ride height/spring rate adjustable system pressurizes or depressurizes the air spring while on a vehicle.