Bicycle Measurement Term Definitions

Effective Top Tube Length: a virtual measurement of bicycle frame’s effective length, measured from top most point of the head tube center line, extending horizontally to the virtual intersection of the center line of the seat tube.

Seat Tube Length: an actual measurement of a bicycle frame’s seat tube member measured from the center point of the bottom bracket or crank axle to the top of the seat tube.

Seat Angle: the angle of rise as measured from the horizon to the center line of the seat or center tube of a bicycle frame.

Head Tube Length: an actual measurement of a bicycle frame’s head tube member.

Head Angle: the angle of rise as measured from the horizon to the center line of the head or steering tube of a bicycle frame.

Fork Rake (rake): the shortest distance between the front axle and an imaginary line extending through the head tube downward toward the ground.

Stand Over Height: a vertical measurement of a bicycle frame from the horizontal center point of the top tube or ‘cross bar’ level ground.