• Preface
• What is an "Integrated" headset?
• The Conventional Headset:
• The "Integrated" Headset:
• The "Internal" Headset, yet another twist:
• Important Facts to Realize:
• Frame Preparation
• Marketing this
• Weight Comparison Table
• Appendix Page One - Non-Braking Forces
• Appendix Page Two - Braking Forces

Integrated Headsets Explained (continued)
March 2002

The "Internal" Headset, yet another twist: An "Internal" headset (also known as "semi-integrated", for maximum confusion) is yet another headset type that places the bearings within the head tube (rather than outside the head tube, like a conventional headset does). The key difference between an integrated and internal is THE BEARINGS DO NOT TOUCH THE FRAME with an internal headset. They are contained either by a cup or an aluminum or plastic shim assembly which is pressed into the headtube. One example is the Zero-Stack™ headset. It is an "internal" headset that uses the exact same bearings as an integrated headset. The important difference is that in a Zero-Stack™ headset, a cup is first pressed into the frame, then the bearing is placed in the cup. The bearing still floats around in the cup, and it will eventually trash the cup. This is absolutely superior to an integrated headset because you can replace the cup. The frame will never be damaged by the bearing. Another example is the Columbus-type internal headset. It actually presses a bearing directly into the bike frame.
		(image is linked to its larger view)

The difference is that the Columbus system utilizes a very thin sleeve to take up the gaps between the bearing and the frame. This is certainly better than a bearing rubbing around loose in the frame, but this system again relies on the frame builder to make that head tube perfectly. We manufacture our headset cups to within .0005" accuracy in order to correctly control the bearing's location and press fit. Frame builders typically hold about .005" accuracy at best. This is 10 times less accurate than a conventional headset cup and while it is perfectly fine for building a frame, it just is not close enough for holding a bearing in place properly. Result? The bearing could be held in the frame way too tightly, or much too loose. Either way, the headset will wear out faster and the frame will likely be damaged.

Important Facts to Realize:

Your frame has been designed for a specific headset type. You can't convert an integrated headset frame to use an internal headset. The frames are too different. Just like you can't convert an integrated headset frame to use a conventional headset. Internal or "semi-integrated" headsets offer basically no structural advantage over the conventional headset. Sure they may be radially stronger, but this isn't really a weakness of the conventional design.