My wife rides a Trek 7100 hybrid with a suspension fork. Since we never go off-road, the fork is just extra weight. I've got the idea of replacing it with an inexpensive carbon fork but since hers is threadless, I believe I've got to buy a new headset and stem along with the new fork.

Is my thinking correct or is there another way? If it looks like it may cost too much just to upgrade this bike I may just buy her a Trek FX series bike. We've been doing some nice long rides and I think the hybrid is slowing her down.(sure slows me down)

Or are there threaded forks out there I could use? I haven't been able to find any at the online bike sites.