I have a Never Been Built '84 Schwinn super sport frame. It did not come with a fork. I need to source a 1" threaded fork. I do not have an existing fork to measure. I also have none of the associated hardware that goes with the headset, (ball bearings, adjusting and locking nuts). The headset is a Tange falcon.

The distance between the centerlines of the upper and lower bearing races, (As close as I can guess as to the center of the ball bearings) is 212 mm.

What would the appropriate steering tube length be?

Thanks for your help!

Gary

Measure your frame's head tube length in millimeters. Add 35.3 mm for the Tange Falcon headset stack height. If in doubt you can go a little longer because you can insert a shim under the lock nut but you can't go any shorter.

Measure the frame's head tube, then go to the Tange site and look up the stack height of the headset. Add the two and that's the correct steerer length, which will need to be threaded 1" down.

BTW- Don't forget to add for any spacers you might need such as a cable hanger or lamp bracket which you'll be putting ubder the top nut. I also add about 2mm on general principles to leave some room for error or future changes.

Forgive my ignorance, but, between what two points do I measure the head tube length?

From one end to the other.

You're measuing the tube itself, not including any headset parts, because you're factoring the headset based on the Tange spec.