Labcanary
One potato, two potato, click
@Rorschach I reckon I've got a 56mm loose ball bearing in a race you can have. I'll check and let you know.Great info, cheers
I've got the first type and bent one of the bearing retainers - a bearing fell out but I managed to stick it back in and (gently) bend the retainer back in. There's a Trek dealer near work I can go and chat to and see if they can help.
I was hoping I could get away with using the existing races for sealed bearings, but it looks like a whole new headset job, or the cheap version of a new set of lower bearings for the existing one.