Headsets for tapered head tubes & fork shafts
In addition to forks where the steerer tube diameter stays the same over its entire length, there are also fork steerer tubes whose diameter tapers towards the top ('tapered'). Frequently-used diameters at the wider, lower end of the steerer tube are 1.5 or 1.25 inches, tapering to 1 1/8 inch at the upper end. A wider steerer tube at the lower end increases stability, stiffness and reduces the risk of breakage in this area. For these tapered steerer tubes, you need the right headset to be able to fix the fork to the head tube. The matching tapered threadless headset can be external, semi-integrated or fully integrated for the upper and lower bearings. A combination of different headset bearings is also sometimes possible.