I have only been able to find a headset that measures 1-5/16" on the small end of the bearing cup that goes into the headtube on the bike. All of the bearing cups I've found are 1-3/4" on the large end and take a large diameter bearing. The headset bearing cups I have 1-5/16" bearing cup o.d. but the large end measures 1-5/8". Where do I find a headset like that?