In some cities, bicycle riding is on the rise and so is bike theft. For instance, the Los Angeles Times reports that bike thefts in L.A. rose by 29 per cent in 2009. Leading bicycle lock maker Kryptonite claims that the lock you choose depends upon where, and for how long, you leave your bike. Most locks offer a system that allows you to mount your lock on your bike's frame. The lock you purchase--a vast majority of the time--comes with everything you need to get it done.
Locate the mounting bracket kit that came with your lock or inquire with a bike shop about ordering one. Most locks--"u-locks" and cable locks--come with a mounting bracket and every thing you need to mount a bike lock to your bicycle's frame. In most cases, this kit will be sufficient to securely mount your lock.
Clear any dust or dirt from the portion of your bicycle's frame known as the seat tube. This part of the frame extends from the where the seat post enters the frame downward. Keeping this area clean and smooth will allow the mounting bracket to sit properly.
Loosen and undo the plastic mounting bracket so that you can wrap it around the seat tube of the frame. Usually this involves removing a screw (either by hand or with a provided Allen wrench) and sliding the plastic strap from the ratchet system that tightens the bracket when placed on your frame.
Place the rubber strip that comes with the mounting kit on the area of the frame where the bracket will go. This strip protects your frame and gives the assembly better grip.
Place the plastic mounting bracket around the seat tube of the frame over the rubber strip. Slide the strap of the bracket through the ridged ratchet system as far as you can by hand. Replace the screw you removed in step 3 and begin to tighten. Do not tighten the screw all the way until you have pushed the strap in as far as it will go. You can use a flathead screwdriver in order to exert more force and push the strap past more ridges.
Tighten the screw all the way after the bracket is secured to the frame and does not move. Be certain that the portion of the bracket that accepts your lock is positioned properly. On some frames, the lock will be situated in the "triangle" portion of the frame. On other frames, there is no room. In these cases, affix the lock to the bracket so that it sits on the side of the bike parallel with the seat tube.
Slide the lock onto the mounting bracket. Some systems have a button that needs to be depressed or pushed down so the lock can attach and detach. On others, the lock slides right into place.
If there is no room for your lock in the "triangle" or centre part of the frame, take care when positioning it parallel to the seat tube. The lock should be on the non-drive side of the bicycle (the side opposite the chain). It should be close enough to the seat tube so that it does not interfere with pedalling. Mounting a bike lock to your frame obviously adds extra weight. This can make the bike handle differently. Often the lock makes noise as you ride. While this is normal, many locks--even heavier locks--distribute their weight evenly in a good messenger bag or backpack. Consider this option before mounting a bike lock to a frame and sacrificing performance.