Parts and Accessories
If it can be removed, it can be stolen!
Maybe it is better said that if it can be removed, it will be stolen! Adjustable bicycle seats are a good example of parts that are stolen. You may ask, "Why would anyone want to sell a stolen bicycle seat?" The answer is to sell to someone who has a bicycle without a seat! It's an ugly cycle. There are often bicycle parts as well as stolen bicycles (as well as other stolen goods) are sold at The United Nations Plaza at Seventh Street and Market Street (catty corner from the San Francisco Bicycle Coalition offices). It is a good idea to etch identifying markings on anything removable to aid in recovery, but better than that is to secure your bicycle parts so that they can not be removed easily.
Low tech method of securing parts
The low tech method to secure your wheels and seat is to remove the quick releases all together and bolt them onto the bicycle. This may make changing a flat tire harder, this will slow down and deter thieves. If you want some overkill, use Loctite Red Threadlocker (you will need heat and a wrench to remove the bolt). The other low tech method is if you have a removable seat, take it with you--ALWAYS!!! To protect your wheels, always lock them with a strong lock.
Mid tech method of securing parts
Pipe clamps can be used to secure quick release hubs. Bicycle seats can be locked to the frame with a cable. These methods will slow down and deter all but the most determined thief.
High tech method of securing parts
Many bicycle accessory manufacturers have designed locking skewers that will not release your wheels without a special key. While protecting your wheels, they also make locking your bike quick and easy since you only have to lock your frame to something secure.