A stationary exercise bicycle is provided having a frame, a resistance member, a drive assembly, a right pedal, a left pedal, a seat and an adjustable seat mechanism utilizing a rack. Assembly and disassembly of a three piece crank arm assembly is accomplished without requiring the assembling and disassembling of the entire drive assembly. The stationary exercise bicycle also provides a variety of users with an optimum seat position and with a convenient latch mechanism to adjust the position of the seat.