Johnny Corts is auctioning his custom FBM to help support Mikey Aitken... - This is custom FBM frame that he built around 3 months ago. It has a 20 3/4 toptube length, 75 degree heatube, 71 degree seatube, 11.5/8 bottom bracket height, and 13.3/8 slammed backend length. The toptube is 1.3/8 supertherm, the downtube 1 1/2double butted heat treated, chainstays 7/8 x .035, seatstays 3/4 x .035 with a mid bottom bracket and integrated headtube with gyro tab holes, and weighs about 4.5 lbs.