Originally Posted by
tallbikeman
However, a frame issue has nothing to do with a loose headset.
Quill stem is the correct word. I am a fan of quill stems. You are right on tracking instead of trail. Trek had a 1 1/2" threaded steerer tube. These were only on the market a couple of years when ahead set came along and everything went unthreaded. I could not find a new 1 1/2" threaded steerer tube suspension fork, only 1 1/2" unthreaded ones. My wife did not want a solid fork. I thus was stuck with buying the right ahead set type steerer bearings and the appropriate 1 1/2" unthreaded fork along with an ahead set stem. Finding the right size steering bearings and cups was a maze of measuring because several different headset bearing standards have been sold over the years. The Trek has been a favorite bike of my wife's for years now so it got repaired.[/QUOTE]
I will almost guarantee that the Trek 4500 didn’t have a 1 1/2” headset at any point in time...especially if it had a threaded headset to begin with. It had a 1 1/8” external cup headset. The conversion is relatively straight forward and finding a headset isn’t all that difficult. Internal bearings are kind of funky but external cup is fairly easy. I’ve done the conversion many times.