Idle headset question
 

How would you make half a headset work?

Look at this bike I found on Velospace!

http://velospace.org/files/takhions.JPG

http://velospace.org/files/takhionsss.JPG

How the hell...?

The bike has an internal upper bearing, and the top cap works in a way similar to threadless systems to adjust the bearings.

About the only way I can think of is that there is a cartridge bearing that is a press fit into the very top of the headtube and the steerer is a press fit into the inner race of that bearing. The fits would have to be tight to keep the fork from dropping out of the bottom of the headtube if the front wheel is lifted.

Edit: I just saw FB's posting but i don't think the top cap in the photo is anything but a cover. The topcap of a threadless headset rotates with the fork and this one appears to rest on the stationary edge of the headtube. Also the cap is not at right angles to the steerer but it cocked several degrees relative to it as it looks parallel to the top tube.

Whatever's going on in there, it's pretty damn neat and clever.

I suppose so, if you're the type that can pedal while standing on your head. Unless of course it was made for an orangutan.

http://www.roadbikeaction.com/conten...%20%281%29.jpg

http://photos-a.ak.fbcdn.net/photos-...28_7367805.jpg

http://img862.imageshack.us/img862/9340/1004849.jpg

http://velospace.org/files/t_formula1num5.jpg

Hoo boy

http://farm7.static.flickr.com/6165/...da346d15_z.jpg

Wow. Just wow.

Integrated seat mast yet to be cut, obviously

IMO, the easiest way to make that to work is to use something like a quill stem center bolt, and attach it to a top cap or something and then in the bottom another cap welded.

Those russian bikes were pretty cool.

There's another bearing under the cap on top of the head tube.

N.B. that's a Soviet-era "Tachyon" time trial bike. Nice catch!