Headset Tutorial: Thanks to FSA

Standard Threadless
What is meant by Threaded, Threadless, Internal, and Integrated headsets?
-Threaded headset cups press directly into the frame. The fork used for threaded headsets is threaded, and a large nut installed on the steerer tube is used to preload the bearings.
-Threadless headset cups also mount directly into the frame, but a star-nut or similar compression device installed in the fork is used to preload the bearings.
-Internal headsets are functionally similar to threadless headsets. The main difference is that internal cups press almost completely into the frame. These are often preferred for their low stack height and clean look.
-Integrated headsets are becoming more and more popular. With integrated headsets, a

Internal Press Fit
bearing (usually a sealed cartridge unit) s directly into the frame eliminating the need for cups.
With integrated headsets, it is not necessary to press cups into your frame, but it is important that the headtube be professionally machined to the proper dimensions to ensure smooth operation.
What are the most widely accepted standards of integrated headsets?
While there are many standards out there, the three most widely accepted are the Cane Creek, the Campagnolo, and the TH standard. All three use angular contact bearings (ACB) which we find to be best suited to handle the loads to which a headset is subjected. Each bearing uses its own proprietary ACB standard and are of different dimensions. The bearings are not cross compatible.
- Cane Creek Standard 35°x45° ACB (blue seal).
Integrated
- Campagnolo a 45°x45° ACB (yellow seal).
- TH a 36°x36° ACB (red seal).