[bdun01]

I use a bully horseshoe lock with built in alarm that also came with a pager that goes off if the lock is moved and goes off. The pager works up to a half mile away. I will post a pic in a little of how I place it on my bike/wheel to make it more effective.

 

[bdun01]

I have the lock wedged between the fairings and the tire which holds the lock about 3" off the ground. With the ignition lock the steering still has a little play in it and if it is turned the slightest the lock will drop causing it to sound. It is reliable too, even if someone knew it was there and tried to keep it still it would be nearly impossible. I'm not to far so be prepared to find me furious if you set it off! Ha

 

[bdun01]

Honestly if you plan to have the chain actually prevent theft then any chain that you use that fits in the passenger seat won't do anything. The only chain that would fit in there would be something someone could easily cut with a pair of pliers. The disk lock will probably good if your office is where you can hear the alarm, then you could be out there before they get away with your bike.