Abstract: A bicycle seat which can be adjusted by the rider while riding within a range of fore-and-aft positions comprises a pair of telescoping tubes (20, 16) with the outer tube attached to the bicycle's frame (18) and the inner tube connected to the seat via a member (46) which extends through a slot (64) in the outer tube. A bungee cord (26) is connected between the seat and the front end of the outer tube so as constantly to pull the seat and the inner tube forward. The inner tube has a series of holes (60A to 60E) connected by a groove (62) and a detent cylinder (58) has a spring-loaded detent plunger (54) which extends into one of the holes to lock the inner cylinder in position. The plunger is connected to an operating lever (50) by a cable (52) so that the rider can withdraw the plunger from a hole to move the seat forward or backward.