Core77

Great idea, but it only works for a drop bar road bike.

Also, I would want to make sure that the frame is secured primarily. If the stem/bars can be removed with an allen key, the frameset would not necessarily be secure.

I am not trying to shoot holes in the idea. I think it is a great concept and I realize that it is just that, a concept and not a refined design.

that's hot. special bars, special seatpost, maybe special bike. might have to telescope seatpost to fit smaller bikes, as bars are at least 380mm wide whereas seatposts are usually 250-ish, and can't go further down in the seat tube due to other stuff. . . blah blah blah details. Locking skewers are nice.

lock em up like these cats

http://www.youtube.com/watch?v=b2885aR6o6s

Why not a simpler design? (although that one is pretty ingenius). Most if not all bicycle frames are of the hollow persuasion, and have enough space to conceal a braided metal rope. With a small hole to pull the end of the rope/chain from, you could use it to wrap around the oh so precious bits of your bicycle, and then lock it up. To make it easier, pieces of the bicycle could have reinforced metal loops or the like to secure them easier, and the frame itself could have a second hole that would serve to lock the rope in place. By no means an elegant or pretty solution, but an effective one that i would think would not be too hard to implement.

Do you need to readjust your seat hight every time you leave some destination? I'd rather carry extra u-locks. (I'm paying the bills as a bike messenger)
Also, the circular key in the graphic is vulnerable to picking by way of bic pen, look it up, it's not even hard or time consuming to do. double sided flat keys are harder to pick. And for the record, the frame and the back wheel are the most expensive parts to replace if stolen.

To me the 'solution' will turn out to be a dirty one :

Most seatpost have been (to a certain extent) greased, for easy adjusting it's height.

Which means that by using it s the lock, you'll get your hands dirty (not fun with grease/dirt, it's very persistent :))

On rainy days, it'll also get rain in the hole where your seatpost came from, might wash off your grease, and introduce rust on places you didn't expect (although that last argument is, i must admit, fairly poor)

Nice idea, but there's quite some caveats to keep in mind.

Just ride a beater for when you need to lock it up.... ride your precious when you want to ride

Lockable quick releases and a decent u-lock.

I really like this kind of clever thinking, but this one needs some work. Seat posts are shorter than drop handlebar widths, and any drop bar that extends back beyond the head tube as shown would possibly be unridable. The seatpost would also need to be made of hardened material.

These are probably surmountable obstacles, but I don't know how to get around the fact that seatposts are just greasy. This also doesn't solve the problem of stolen saddles.

I just happened to be working on a similar concept for my design final at Pratt Institute. I've got some images up. The difference in mine is the top tube
unfolds and rotates from the frame in such a way to create a space inside the frame suitable for locking around a vertical or horizontal post or bar.

I have them uploaded here:

http://www.coroflot.com/public/individual_set.asp?from_url=true&sort_by=1&set_id=133183&individual_id=176919