Abstract: Bicycle pump apparatus includes a cylinder portion, a piston portion, a handle portion, a seat mounting portion and an air discharge portion. The cylinder portion includes an elongated tubular section, the tubular section having an external diameter slidably engageable snugly with a seat post receiving section of a bicycle frame. The piston portion includes an elongated rod member having a length slightly longer than the tubular section. A transverse plunger member is affixed adjacent one end of the rod member, the plunger member having a diameter substantially equal to the internal diameter of the tubular section to provide a snug fit therebetween A transverse guide section is disposed adjacent an opposite end of the tubular section aligning and maintaining the rod member along the centerline thereof.