I am an admitted neophyte when it comes to integrated headsets, so apologies in advance if this is an obvious question.

I recently picked up a NOS Ti frame to build up for my wife and I am having a hell of a time with the headset.

I am attempting to install a Chorus integrated headset and the bearings will not seat in the frame. I already tried to install another integrated HS and ended up having to destroy the bearings to remove them as the fit is just way too tight, to the point that the install ruined the preload on the sealed bearing units. Everything I have read leads me to believe that the bearings should slip right in, but these absolutely will not. Are there integrated HS that need to have the bearing (semi) permanently pressed in, do I need to ream out the headtube, or is there something else I am missing?

Before I ruin another HS, I figured I'd reach out and see if anyone had any input. Thanks in advance!

For reference, this is what I am looking at with everything snugged down pretty darn tight:

Do know what spec the frame was made with WRT the headset? There are similar looking designs but with slight enough differences that mater. Andy

Thanks all, I did end up using calipers and determined the bearings were IS41 spec. New HS incoming, thanks for the help!

Perhaps the frame was machined for a cane creek integrated headset?

they're different..