What's the difference between a Threaded and Threadless fork?

[kphy]

I want to know the difference between the two forks ( threaded and threadless) I'll be replace my vintage peugeot's fork because it got it bent in a car collision. I need a replacement but i don't know what mine is because i have no knowledge with specifying the two forks.

[Alex Ramon]

I'm guessing your headset is <a href="http://bikeride.com/overhaul-threaded-headset/">threaded</a>. Here's a video that shows what a more modern <a href="http://bikeride.com/adjust-threadless-headset/">threadless</a> headset looks like.

Threaded headsets are called that because they thread on to the top of the fork. The stem then slides into the fork and tightens using a wedge. To remove the stem, loosen the top bolt a little bit and tap it with a hammer to knock the wedge free.

Threadless headsets simply slide on to the top of the fork ,and are fastened by a bolt on top of the stem that threads into a star-shaped nut down inside the fork.