The Ostro is Factor’s superlight aero race bike that likes to win. We love the T47 bottom bracket that provides a friction-less feel, easy maintenance, and a secure fit. Fit Range 5'7" - 5'10" A. Effective Top Tube 542 mm B. Seat Tube 502 mm C. Seat Tube Angle 74° D. Head Tube Angle 72.5° E. Head Tube 155 mm F. Stack 542 mm G. Reach 384 mm H. Standover Height 781 mm.