# zero stack vs integrated



## mountainjoo (Mar 26, 2009)

are these two headsets interchangable? i was on a ride last sat and i overheard another rider at the trailhead talking about his khs xct555 and how he is using the new CK InSet headset; originally, his khs came with a zs headset. is he putting his frame in danger or what?


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## boomn (Jul 6, 2007)

"integrated" is a term that is misused all the time with mountain bikes. A true integrated headset does not have separate headset cups; the bearings mount directly in the frame. 

Zero Stack (also called semi-integrated on internal) headsets have all the same parts as a normal headset but they are designed so that the headset cup sits hidden inside the headtube of the frame. The stock headset on the Fisher and the new CK InSet are both this same type. 

To make it more complicated, there are some different sizes of internal headsets so not all frames and headsets are interchangeable. But I believe the CK is the same size as the most common standard used by most companies


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## Fix the Spade (Aug 4, 2008)

Right, the King Inset and Creek ZS are both _semi-integrated_ headsets (also referred to as _Zero Stack_ or sometimes _Internal_).

They are different to integrated headsets (as found on most bmx's)
in that they do not use the head tube to seat the bearings. In the context of a steel bmx having the bearings run directly against the head tube isn't a problem, steel is very hard wearing and bmx frames don't last that long anyway. On an alloy mtb frame they would wear out the head tube over time.
Creek integrated haedset are marked as IS.

Semi integrated headsets work exactly the same way as threadless (standard) headsets in that the bearings run against the cups of the headset and not the frame.

King Insets have a 44mm diameter, same as a Creek ZS. If you can persuade him get him to go to a bike shop and get them to measure the head tube, they'll have a specific gauge for it. It'll save some doubt when buying.

#edit, curses, beaten to it!


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