People often ask me what the best type of lock is. There are all different types of locks of varying size and price. So which one is most effective? Should I buy a 10 pound square link chain? Or will I be fine with a lightweight cable lock?
It is my belief that there are only three relevant categories of locks. Within each category no one lock offers more protection than another. To understand the three categories of locks, we must understand the three types of bike thieves.
Category 1: No Lock.
If you leave your bike unlocked outside any one can take it. In this case the thief is a criminal of opportunity. He wasn’t planning on stealing a bike today, but seeing yours unlocked and unattended he’ll take advantage of the opportunity to grab a free bike. Any lock no matter how small will deter this criminal, because as soon as it requires some amount of work to take the bike he is no longer interested.
Category 2: Cable Locks and Small Chains.
If you lock your bike with a cable lock or small chain, the thief now requires tools of some kind to get it. This means that the thief has to leave their house with the intention of stealing a bike. Just by putting some form of lock on your bike (no matter how small) you have drastically reduced the number of potential thieves that may take your bike. However these locks can be cut very easily with a pair of bolt cutters ($10 at any hardware store).
Category 3: U-Locks and Square link chains
If you lock your bike with a U-lock or square link chain (Kryptonite New York lock) the thief will require some heavy-duty cutting tools. There are only two kinds of tools that I know of that are capable of cutting these locks. 1: Oxy-acetylene cutting torches. (It is unlikely that someone would drag a cart with the requisite gas tanks out onto the street and fire a torch up to cut your bike lock.) 2: The more likely tool: a cordless circular saw or angle grinder, equipped with a ceramic blade. These tools may well cost more than your bike is worth. That in itself is a good deterrent, further shrinking the pool of potential thieves. However if someone has these tools there is nothing that they can’t cut. So once you are in this category of locks, increasing the size of your lock will offer no more protection what so ever.
My lock of choice (the one I use, on my bike, in the city, everyday) is a small U-lock. It offers the best protection in the smallest package. I chuckle to myself when I see people lugging those huge 10 pound chains around. Sometimes they sling them around their shoulders like Rambo. Sometimes they wear them around their waist like a belt. Sometimes they have a backpack dedicated to their lock. Whatever the case it looks like more of a nuisance than it’s worth. I know that my light weight U-lock that I can slide into my backpack (and cost about a tenth of the price of one of those huge chains) will keep my bike just as safe as their gargantuan chains.
The truth is locks are only a deterrent of theft. If you leave your bike outside, and someone really wants it, they’ll get it. For every lock there is a tool that can cut it. If you really don’t want your bike to be stolen don’t keep it outside.