Originally Posted by
dr.raleigh
I don't see why it would be different because its a 1 1/8, or is it likely to be different?
could be. Your orginal head tube was built to have a threaded head set upper race pressed on the outside of the tube. There is no sure way to see how close to tolerances the inside diameter of the tube is without measuring. If it is a bit too big the threadless headset will not stay in place, if it is bit too small you will ruin the headtube if you try to hammer it in there.