# Can somebody explain the difference between zero stack and integrated headsets?



## xcguy (Apr 18, 2004)

I've never used either but I've had salesmen at various bike shops describe the same items as either a zero stack or integrated. How's a peep to know when he's looking at them? And why is one or the other used instead of what I'd call a "normal" headset?


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## Speedub.Nate (Dec 31, 2003)

Zero Stack aka internal aka "semi-integrated" is very similar to a traditional threadless headset, but with the cups sunk into an oversized head tube. You will see a thin lip of the cup above and below the head tube.

Integrated features a head tube that has been machined internally to act as the cup. The bearing fits directly inside the head tube.

There are a couple of benefits to both of these: The larger head tube diameter provides more weldable area for oversized frames tubes to be connected to, making for a stronger junction and perhaps avoiding tubing manipulation to ovalize / elongnate the tube end to match up to a conventional head tubes smaller profile. They provide a lower possible stack height, which can be especially beneficial to 29" frames, though I haven't seen 29" frame manufacturers embrace them as I'd anticipated. I've heard from a product manager that warranty claims for ovalized head tubes virtually disappeared after the switch to Zero Stack. And integrated is potentially a few grams lighter, due to the lack of cups.

The potential downside to integrated (no cup) headsets is that if the bearing gets sloppy, it can ruin the head tube, with no practical way to repair it.


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## Speedub.Nate (Dec 31, 2003)

...and here's a pic of the flange of a Zero Stack headset cup "peeking out" at the bottom of a oversized ZS head tube. This is the telltale difference between Zero Stack (or similar looking but larger 1.5 standard) versus the cupless integrated.

https://forums.mtbr.com/showthread.php?p=1189926









Here is a Zero Stack cup being pressed into the head tube:

https://forums.mtbr.com/showthread.php?p=1190007


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## newaccount (Jan 3, 2007)

I haven't taken apart my bike to check, but will a semi-integrated headset fit into a frame made for an integrated headset? Thanks.


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## Speedub.Nate (Dec 31, 2003)

newaccount said:


> I haven't taken apart my bike to check, but will a semi-integrated headset fit into a frame made for an integrated headset? Thanks.


Depends on the bearings used for the semi-integrated / zero-stack headset you've got in your hands. I don't know the answer, but there's a chance they're comparable.

Have you got something on-hand that you want to put into use?


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## mtnbiker72 (Jan 22, 2007)

Integrated was used on MTB's in the early 2000's (such as Schwinn ICBM and Giant) but it has since been almost exclusively a Road Bike thing. The ZeroStack has really taken over on MTB's (for example Giant uses ZS on their MTB's and integrated on their Road Bikes now)


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## newaccount (Jan 3, 2007)

It's for a Specialized Sirrus. The spec is for an integrated headset. I have a spare semi-integrated headset laying around. I'd rather know if I need to order another one before taking the fork apart. Thanks.


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## mtnbiker72 (Jan 22, 2007)

The Specialized uses the IS (41mm) standard...so any of the IS headsets from Cane Creek or FSA will work


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