How to Lock Your Bike—From a Locksmith's Point of View
Many people say that the purpose of locks is to keep honest people honest, but I say that the purpose of a lock is to give a would-be thief enough trouble to make them give up their attempted theft of your property, in this case, your bike.
Correct Bike Locking
If you don't lock your bike correctly, a thief will be able to steal part or all of it. First, choose the most immovable object available to which you may lock your bike, and then lock it in such a way as to make it as difficult as possible to steal. If you lock your bike to a parking meter with a cable lock, for example, the thief may be able to lift your bike over the head of the meter. If you lock your bike to the same parking meter using a U-lock, however, theft in that manner would not be possible.
Thieves don't just steal bikes; they steal bicycle components, particularly wheels. For this reason it is important that you secure not only your frame to the immovable object, but also both wheels. Quick-release hubs and seatpost clamps make wheel and saddle theft easier. If you have quick release hubs and don't lock both wheels, you make your wheels a prime target. If you have a quick-release seatpost clamp you need to lock your seat as well.
In the illustration below I attempt to show basic correct bike locking technique. There are many variations. but the idea is that the frame of the bike is securely locked to as immovable an object as is available and that the other steal-able parts of the bike are also secured—in the case of the bike in the illustration, the wheels, which are secured with a cable.
One Correct Way to Lock a Bike
Types of Bike Locks
All locks can be defeated. As a professional locksmith, I was able to defeat any bike lock in less than twenty minutes, but I was in no rush and I could use any tool I wanted. Bike thieves have to work fast and are usually, but not always, limited to hand tools.
The locks I prefer to lock up my own bikes with are Kryptonite bike locks. They have pick-resistant cylinders and are made of hardened steel that is hard to cut. Pick resistance and difficulty in cutting are the most important features to look for in a bike lock.
There are many good brands of bike locks. To get the best kind of bike lock for your needs, consult with your locksmith or security professional.
Pictured below are a couple of bike locks, a cable, and a chain. I will discuss the relative merits of each.
The "U" Lock
The U-type lock revolutionized bicycle locking when it was introduced decades ago and is still a good choice today.
The vinyl coated, braided steel cable (pictured above) is effective when used with the U-Lock for two reasons. First, because it gives you a way to lock both wheels (see Correct Bike Locking section and illustration above). Second, because cutting the cable would require a different tool than cutting the lock would. However, to take advantage of this attribute of braided steel cable you would want to lock it with an independent lock, such as an American A700 padlock.
Since the vast majority of bikes are locked with only one lock, locking your bike with two locks makes yours one of the most secure on the street.
New York Noose
New York Noose
So named because so many cyclists carry this jacketed, heavy, hardened chain around their necks. This chain is a good choice because it is almost impossible to defeat without power tools. Add a high security padlock (and an immovable object) and you can consider your bike secure. Make sure, as always, to lock everything steal-able on the bike, not just the frame.
Small U-Lock or Disc Lock
The Kryptonite Disc Lock adds a new dimension of security with its size, shape, and key system. One of its chief advantages is that it does not offer the opportunities for attack that the conventional U-lock offers. Since the conventional U-lock has been around so long, thieves have devised some effective ways of defeating it. Redesign has alleviated much of this problem; many thieves might have trouble finding a point of attack on this smaller U-lock. I recommend using it with the New York Noose or steel cable and a conventional U-lock for the best you can do in bike security on the street.