A sturdy bike lock is a vital part of keeping your cycle safe. One of the most popular types of cycle lock is the D-lock or U-lock. Some of the most popular U-locks are made by the Kryptonite company; these are so popular that the term "Kryptonite lock" is sometimes used to mean "U-lock." U-locks are sturdy and easy to use, but carrying one around can be a challenge unless you fit it securely to your bike's frame with a carrying bracket.
The simplest way to attach a Kryptonite lock or similar U-lock to the frame of a bicycle is with a storage bracket. The bracket consists of a plastic or metal frame which fits around the bar of the lock, holding it securely in place. Most commercially-available locks come with a bracket included; this bracket will be sized to fit the lock. For those who have a lock but not a bracket, bicycle shops sell adjustable brackets that can fit a wide range of locks.
Fitting a bracket
Most brackets are designed to attach to the seat tube, the central part of a bicycle frame forward of the rear wheel. Some brackets attach using straps which must be tightened around the tube, while others have clamps or clips which fit around the tube and must be screwed into position. Most bicycle shops will fit your lock bracket for you, particularly if you are buying the lock and bracket at the same time as your bicycle.
Using the bracket
The crossbar of your U-lock should fit snugly into the bracket, with the U-shaped shackle projecting forward from the bracket. If the bracket is fitted correctly, the shackle won't get in the way of your legs as you pedal. When putting the lock into the bracket or removing it, press firmly but gently until the lock fits in place. Yanking the lock out can damage the bracket, while pushing it in too lightly can lead to it falling out.
Alternatives to brackets
A bracket is the most effective way to store a U-lock, but there are a number of alternatives. On bicycles with wire baskets, it may be possible to fit the lock to the basket, locking it through the wires. Alternatively, some riders sling the lock over the handlebars or lock it to the top tube of the frame. The problem with locking directly to the frame is that the lock will tend to swing while the bicycle is in motion, getting in the way of safe riding.