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If you’ve ever built a bike up from scratch then you may know that headsets can be a bit confusing. I mean, it’s basically a whole different language! Let’s dive into what the heck ZS and EC mean, and as a bonus, we’ve added in the table of all the headset information you’ll ever need for Sour frames a la mode.

For all the headset sizes for Sour frames, just scroll down below.

To keep this article short and sweet, we’re only going to discuss Sour headset sizes, and because we don’t make any integrated type head tubes with a drop-in style headset as is common on carbon frames, we’re just going to pretend they don’t even exist!

The headtube is the tube your fork goes through, and the bit where your stem clamps on is called your „steerer tube“. Lot’s a tubes. So to decide on which headset to use, we need to know a few measurements:

– Inner diameter of the headtube up top, as well as down under.
– Outer diameter of the steerer tube up top, as well as down under.

Put these measurements together and you’ll end up with the sizing information needed to get the right press-in cups to complete a headset. In the case of a Sour Crumble with a tapered steerer tube like you’ll likely have with a suspension fork, you’ll have something like this: 44mm/28.6mm upper (headtube/steerer), and 44mm/40mm lower (again, headtube/steerer).

Okay. Everything is sized up and ready to be specified further. Let’s go.

Next step is to add the cup types to your measurements. This is often specified by the manufacturer, and in the case of the Crumble we recommend a ZS/EC combination. Those letter are just abbreviations, no need to panic. „EC“ means External Cup, pretty self explanatory, and „ZS“ means Zero Stack. Zero Stack just means that the cup is recessed in the headtube instead of having a cup outside the headtube.

Put all this together and you get the headset you need for the example Crumble frame, check it out:

Upper: ZS44/28.6mm
Lower: EC44/40mm

Cool, huh? For more headset sizing for all of our frames, check out the table below!

Purple HazeAluminium (1 ⅛“)ZS44/28.6ZS44/30
Carbon (tapered 1.5 -> 1 ⅛“)ZS44/28.6EC44/40
CluelessAluminium (1 ⅛“)EC34/28.6ZS44/30
Carbon (1 ⅛“ – 1.5″)EC34/28.6EC44/40
Homebrew/AllroadCarbon (1 ⅛“ – 1.5″)EC34/28.6EC44/40
Pasta Party100-120mm (1 ⅛“ – 1.5″)EC34/28.6EC44/30 or EC44/40
Crumble120-140mm (1 ⅛“ – 1.5″)ZS44/28.6EC44/40
Big Fun140-160mm (1 ⅛“ – 1.5″)ZS44/28.6ZS56/40
Double Choc140-160mm (1 ⅛“ – 1.5″)ZS44/28.6ZS56/40
Bad GrannyZS44/28.6EC44/40