In recent years, the U.S. big three ", Specialized and Trek road bikes are beginning to change all the thread 45, even the FACTOR of the latest models Ostro VAM also began to use T47. So today we're going to talk about what is "restoration" or progress.

First talk about the advantages of the screw axis, the biggest advantage is easy installation, can be screwing in frame directly coated with grease, almost zero to the requirement of technology and tools, only need to pay attention to is that don't put in the wrong direction. The emergence of another is BSA30 specifications in recent years, the center axis of the need to use the bigger one wrench. Have basic ability of people at home can tear open outfit, this to some of the workmanship is higher for foreign area is the use of large cost advantage.

Thread structure determines the axis and the frame is not the sort of large surface contact, the probability of sound will be lower. Of course, correct installation of pressure into the type axial actually is not so easy to sound. In general, the use of the screw axis or a lower cost.

Here are for the disadvantages. The first is the weight of the frame five-way area than 45 heavier pressure into the type, the screw type 45 must be inserted into the aluminum cover, so compared with the total carbon PF86 and PF30 series of five heavy on the 20 to 30 grams. Compared with axial pressure into the type of plastic shell, screw axis of aluminum shell are slightly heavier.

Another is traditional BSA if use thick axis of tooth plate, will need to use the thinner BSA30 bearing axis, the axis of the poor durability. T47 specification which do not have this trouble.