Internal cabling undoubtedly looks stylish, but can lead to costly orgy of work in the workshop. It is also a tiresome and poorly kept secret that headset bearings for internal routing are not of the best quality, which then break extra quickly.

This is now definitely a thing of the past - because Chris King is jumping on the bandwagon of headsets with outer shells. King headsets are famous for being very durable, and the lifetime guarantee on the product vouches for this. Despite the modern approach in the case of the Chris King AeroSet 3, there's still a dose of tradition in it: The headset is pressed into the frame, the head tube must measure 1.125" at the top and 1.5" at the bottom. 

This press-fit version is no longer found on too many frames today, Chris King presents the headset news in combination with a Moots road bike frame. A drop-in version, where the headset shells are not pressed in but simply inserted into the frame, will probably not be long in coming.

chrisking.com