you can probably* switch to a threaded setup, but you'll need a new headset, fork and stem. there are threaded headsets available in 1" and 1 1/8" (among others), so get a headset for whatever size headtube you have, threaded fork with the right size steerer, and a quill stem and you're ready to go.

i can't really think of a reason to do this other than aesthetics, and that's a big load of cash to drop for aesthetics.



* unless you've got one of them new-fangled internal headsets, then you're stuck with what you got.