Individually, the Bike U-Lock and Chain Lock are strong deterrents and priced right.  Together you follow the direction provided by the national bike registry to keep your bike from being stolen.  Use the bundle of physical security, register your bike and use common sense and your bike should be safe from theft. Many bikes are easily stolen because they are not locked. Your first line of defense is a good lock, properly used. Lightweight cable or chain locks are easily cut and offer little protection.

Many bikes are stolen from home (yard, porch, garage, dorm room, etc.) Store your bike in a secure place when not in use. If you are not sure your storage is secure, use your lock!

Register your bike in a national database, like  http://www.nationalbikeregistry.com/register.html.  The National Bike Registry database is accessible to law enforcement throughout the country. No matter where a bike is stolen, or where it is recovered, the owner can be identified. The NBR Certificate of Registration can be used as proof of ownership if your bike is recovered, or for your insurance claim if it is not found.

U-Locks vs. Cables. What is the correct choice? Although they are frequently used, the lightweight cable or chain locks no longer provides adequate security in most areas. In neighborhoods with a known bicycle theft problem the best choice is a strong, reliable U-lock. And remember, two locks are better than one!

Combine a cable and a U-lock, or even two U-locks, when securing your bicycle. The more time and trouble it takes a thief to attack your bike the less likely it is that your bike will become a theft statistic. Solid Steel is the Strongest -- the ideal steel is hardened against cutting yet maintains flexibility,