I have a NOS Ridley Supercross frame I’m just getting round to building, but I’m struggling on the headset.
It’s roughly 2008, it is 11/8″, it is intergrated.
As it’s old it shouldn’t have anything fancy. What I can’t work out is how you can tell if it’s 45/45 or 45/36.

A kind soul pointed me to an add for a cane creek that said it would fit a Supercross so 45/36. But I seem to remember something saying Campagnolo type I’ve had so long now I can’t remember.

You need the SHIS enter the measurements, and it will tell you.

You need the SHIS enter the measurements, and it will tell you.

It’s unlikely to be able to tell you what chamfer angle he needs

Still baffled. There are no angles, straight 1 1/8 steered. 42mm internal sis top and bottom.

The Cane Creek finder will need you to give an angle.

42mm should be Campagnolo standard 45/45.

You could make some gauges cut out of card or from a drink can.

If you have bearings of the same diameter, you could try to test with engineers blue, or even a marker pen. Coat the bearing race chamfer with ink, fit into the seat and see if you get a complete fit or just a partial mark, either inside or outside of headtube shoulder.