A mounting specification adjustable front fork mount for mounting on a bike rack on a car roof to cooperate with a quick release for securing a bicycle front fork is disclosed to include a holder having a shaft tube with a protruding portion at each of two opposite ends of the shaft tube, and two mounting tubes each having a first coupling recess and a second coupling recess so designed that the bottom of the first coupling recess and the bottom of the second coupling recess are respectively spaced from the distal end of the mounting tube by a different distance. The protruding portion at each end of the shaft tube can be selectively engaged into the first coupling recess or the second coupling recess according to the specification of the bicycle front fork.