COPDOTS Pen Home Asset Marking System For Your Bicycle - YouTube

I would strongly suggest using a combination of three inexpensive systems to protect yourself from harm and theft. 

And, the reason why is that you want to attract as many witnesses as possible to catch a criminal on the spot. 

And, even if a criminal does happen to get away with it at a particular time at least your property can still be tracked and traced quickly by both you and/or law enforcement.

• Use the copdots pen to protect your bike and all of its parts: Protect your back pack and bike helmet and bike pump and bike tools and many other related items in case these items are stolen from you out on the streets or when they are inside your home or apartment: COPDOTS Pen Home Asset Marking System - YouTube: http://youtu.be/at2t-ob5WZ0
• There are also GPS tracking systems for your bike http://vectortrac.com/. 
• Not to mention, there are personal alarms for walking, running, and biking http://www.dobermanproducts.com/. 

How to Lock a Bicycle and Get a Stolen Bike Back, by Jim Langley

Bike-theft --- it has never happened to me, but I know it can.

The only thing not mentioned in this article here is that you can take your seat off and take it inside of the store with you.

You can paint your bike a bright weird color and make one bike handle bright green and the other one bright purple. You can take one wheel inside with you too. People who steal want a whole bike, not part of one.

They want a bike that blends in with the crowd, not a bike that stands out in the crowd.

Here is another plus: more expensive bikes are special in that the parts must be ordered from the same place the bike was first bought or directly from the brand manufacturer.

The Republic Bike is one good example of the type of bike I am discussing here.

Of course, the thief will also need the owners manual with a special serial number, which they will not have or know because they are not the original owner.

It is good to have a great relationship with a professional bike shop and to buy your bikes from them.

Cheaper brands break down to easily and the parts are always hard to find if at all. And, this alone is why they usually end up in the trash heap.

Some people never learn, they buy several cheap made bikes when they could have had one good bike from a professional shop that would last for many years --- provided it is not stolen.

So take my tips into consideration and also read Jim Langely's article for even more fascinating ideas.  

How to Lock a Bicycle and Get a Stolen Bike Back, by Jim Langley