Ok a different thought .. kind of like #29..
use a hollow tube seatpost, run a cable loop out of the top of the seat post around the seat rails and back into the seat post , then run the 2 lengths of cable down the seat post tube,
and perhaps fix them to a stopper in the end of the seat post..

Or,with the other end secured in a plug that with enough cable length, slides down past the water bottle braze ons,
inside the seat tube , then you can fit a longer bolt in the bottle cage, to keep it from pulling back out out. ..

that should baffle most people with only enough brain power to think of quick grabs.

there are security allen bolts which in the center of the hex socket there is a pin it keeps the common wrench
from going in .. the hex key that goes with it has a matching hole in it's end.

that tamper proof site lacks allen capscrews.. I note. just metric button and flathead.

I use the Bladder bag out of a 5Liter Vin Ordinaire box as my winter saddle cover..

it, not only keeps the seat dry, it makes a saddle seem pretty ordinary too.

It's nice to know there are lots of options available for securing seasts, but where do you guys live that there's such a problem with seat theft? Is there some big market for seats? Do they bring a lot of cash at a pawn shop? I don't recall ever seeing a seatless bike anywhere? Seriously, what's the motivation for stealing a seat?

Use the quick release to quickly release the seat post and take it with you.

and if it rains the seat tube will be a funnel to fill the frame up with water..

Now that Brooks leather saddles are posh many(unscrupulous , addicts?) target them .

Where are these seat thefts happening? Big cities? Inner city? College campuses? I still don't understand. I ride a Brooks B67 and never seen any sign that it's been tampered with in Sugar Land and SE Houston.

Did anyone say Locktite (red level). I just had to grind off some 1/2 bolts due to this stuff.

My thoughts were a) bike chain in an inner tube b) security screws or c) locktite. Other option is to just take your seat with you like you would your computer if you're really concerned about theft. Out of sight, out of mind. Just be sure to cork the seat tube if there's a possibility you'd get water down it.

this seems easy

There used to be an antitheft device just like that. It fit inside the bottom of the seatpost, had a cable to a plug that dropped down the seat tube, and even came with a longer-than-normal bolt to keep the plug in place. Not difficult to remove, but would certainly take a thief by surprise.

I think I originally started this thread. I soldered and used a bike chain. Within about a week the bike chain was gone and someone tried to unscrew the soldered bolts. The solder worked. I still have my seat. I'm not going to reattach the bike chain. Too many would-be theives carry around chain breakers, I guess. I did buy a thin cable to lock it as additional protection to a the U Lock. I also bought a crappy looking cover for the seat.

Fill your hex nuts with either:

aluminum foil+crazy glue (easier to remove if you need to make adjustments).
lead solder (harder to remove, but better theft prevention).

I fill all my hex bolts with this stuff, and no parts *ever* get stolen off my bike since I started.

Buy a folding bike and bring it inside with you.

If you're interested, try talking to these guys: http://www.oemhardware.ca/tamperproof.htm they claim to have metric and imperial fasteners. I don't remember if the microadjusting type of seatpost bolt is a standard metric thread or a more bike-specific one.

I use Pinhead locking skewers, headset, and seat post locks. They work fantastically.

I can't believe it took this long for someone to say Locktite red. Don't you just have to heat it up to break it?

Use a pitlock on the clamp

On your seat clamp bolt, either solder in the head (like the OP did) or red locktite and buy a $8 heat gun from HF.

Loctite red melts at 260C.

The advantage of this is it still permits a bit of easy adjustment from time to time if you change cycling shoes or your saddle gets bumped and askew, or if you have to lower the saddle to get it into a trunk.

Me too. Right now I am using a cable lock through the seat rails and the seat stays.

Another option is to visit your local hardware store and put together something like this:

http://www.bikeregistry.com/estore/p...0d2bafc4a1ea66

+1. The vast majority of people who steal things aren't going to take the time to mess with this. And the ones who do will probably know how to strip just about anything they want off your bike...