Or just run ZS44 top and bottom, no further reduction needed.Would leave me to believe you'll need a 44zs/44ec headset, potentially with a 1.5-1-1/8" reducer crown race if you're running a straight 1-1/8"
- 44mm standard head tube designed with external bottom cup for taper steerer compatiblity and zero stack top cup for minimal stack height.
https://www.cotic.co.uk/order/framebuilder/solaris/?frame=Solaris_SM_green Check the headset section
But you'll probably want to confirm with Cotic just to make sure
Not sure where you're getting a measurement of 1 1/4" from, as that is only 31.75mm. As eshew says, Cotic specs say the head tube is a straight 44mm head tube that you can put zero stack (or semi integrated) cups into for a straight steerer, or an external bottom cup for a tapered steerer.Morning Ian the head tube is 1 1/4