Measure the internal diameter of the head tube, probably 30.0mm. In that case, you need a 1" conventional headset, and a 1" fork with a steerer length of ~155mm for a threaded headset or a minimum of 200mm for threadless (the recommended solution - threaded headsets and quill stems are inferior)
Measure the internal diameter of the head tube, probably 30.0mm. In that case, you need a 1" conventional headset, and a 1" fork with a steerer length of ~155mm for a threaded headset or a minimum of 200mm for threadless (the recommended solution - threaded headsets and quill stems are inferior)