Your serial number is usually placed on the underside of your bike frame (also known as the bottom bracket shell). Flip your bike over, write it down, email it to yourself, be thankful you have it if your bike gets stolen. If your bike does get stolen make sure to file a police report and give them your serial number, this will throw up a red flag if the thief tries to sell the bike to a shop (like ours) or any pawn shop. It also gives you proof if you see it pop up on Craig's list that it is indeed yours. If you see it pop up on craig's list then contact the police and let them take care of it. This also holds true if you see it out in the real world, you need to remember that you probably really want to have your bike back but the thief wants to avoid getting captured even more.
Keep your bike from getting stolen in the first place! A Kryptonite lock will keep your bike safe and warm, Locking skewers will help with the wheels staying on and the Abus chain lock is a flexible sub for a u-lock but not quite as secure.
Avoid Cable locks (example below) for any in-the-city locking.
Many times they can be cut faster than using a key or combo.
