My bike has as standard:

Upper: ZS44/28.6
Lower: EC44/40

44mm headtube, tapered fork.

On the WC page, i can’t see one which matches my spec

http://www.workscomponents.co.uk/full-headsets—most-common-sizes-10-c.asp

Would one of their other options fit? Stack allowing?

Ta

Bump

This (stack allowing, of course)?

linky

The ZS and EC just refer to whether it’s a zero-stack or external-cup, which makes no real difference apart from to the stack height.

Worth asking if they could mix and match some stuff though. They very helpful with queries.

Ok, thank you. That makes sense.

What Warpcow said – definitely worth checking directly with Works, the guy’s really helpful.

I thought I’d need ZS upper and lower because that’s what my existing headset was. Turned out I needed an EC upper to give the extra clearance for slackening the fork. All made sense when it was on the bike.