Locking Your Bike



  •  Introduction

The information presented here is intended for students in Palo Alto schools, to help them lock their bikes as securely as possible given the type of racks that have been provided for them.

Parking a bike is not like parking a car...everything is exposed and vulnerable. That means that it is important where you lock your bike and how you lock it. The best places for your bike are (in decreasing order of preference):

  1. In your  home or office (lock it to a desk or table if you aren't always there)

  2. In a locked bike room with limited access

  3. In a fully-enclosed bike locker

  4. In a bike rack

  5. Locked to a fence, tree, post or other immovable object

  6. Locked only to itself or to another bike

The rest of this page is for students who can't store their bike inside or in a locker, and it should help you to do the best job possible in your situation. You should always lock your bike as securely as possible. If it is not fully enclosed you should remove any expensive accessories (lights, computer, tool bag). You can't lock a bike securely enough to foil determined thieves, but you can slow them down or discourage them enough that they may move on to another bike.

Thieves don't like to be watched. They prefer out-of-the-way locations to busy areas. Unfortunately, many schools like to put the bike parking in out-of-the-way locations that allow a thief plenty of time and privacy to break your lock. You may be better off using only a frame and front wheel locking job to a post in a busy area than a frame and both wheels locking job to a rack in a hidden location. On the other hand your bike is exposed to many more people in the busy area, and the higher visibility puts it at risk for vandalism.

Always lock your bike to some immovable object. Locking the bike to itself only prevents someone from riding it, but it is easy to carry the bike away and cut the lock later. You should try to lock both  wheels and the  frame to the object, or you can end up with one of the situations shown below.

Oops! Forgot to lock the frame.

Oops! Forgot to lock the wheels.

  • Types of locks

    There are three main types of locks: U-locks, cable locks and chain locks. U-locks cannot be cut with clippers and must be sawed or broken by prying apart the arms with a jack or with levers. Some key mechanisms were easy to pick at one time, but that  defect has been corrected in newer models. Use the smallest U-lock that works for your bike to minimize the amount of space available for thief to insert a jack or levers. Cable locks come in different diameters, and the larger ones are stronger. Some have sheaths that make cutting more difficult. Chains are less convenient to use than cables because the links get caught on spokes and other things, and most can be cut easily with bolt cutters. A good chain is also very heavy. A Cable with a built-in lock is better than a cable with a padlock because the padlock is much easier to cut than the cable. It also means you can't forget part of it, since it is all one piece.

    A good rack will allow the use of a U-lock. Unfortunately, not all schools have good racks, so you might have to use a cable lock. The best thing to do is use both types of lock. Each one takes a different and bulky tool to break, and it is unlikely that a thief will be carrying both.

    A U-lock

    A good cable lock

  • Types of racks and how to use them

    A good rack will support the bike at two points to keep it from falling over, and will allow frame and one or both wheels to be locked to the rack. A good rack should also be fastened securely to the ground so the whole thing can't be trucked away. Good racks are expensive and much less common than poor racks. This section will show you how to best lock your bike to low-quality racks. If you are fortunate enough to encounter a good rack, the techniques below can still be used and will be easy.

    • Comb racks


    These are the lowest of the low in terms of quality. The one shown is slightly better than many, since it does have the horizontal bar down near the ground to support the wheel. Still, the bike tends to fall over sideways, especially if the wheel is narrow compared to the spaces between the bars. The photo below shows the intended usage. Only the front wheel can be locked unless you have a very long cable or chain.

    Here are some ways to make better use of a comb rack. If you have the strength and space to lift your front wheel over the rack you can lock the frame to the rack. The first photo shows the frame locked with a U-lock, while the second one shows frame and both wheels locked with a cable lock. Even better, do both!

    The best way to use a comb rack is sideways, as shown below. This allows frame and front wheel to be locked with a cable lock, and the rear wheel (which also secures the frame) to be locked with a U-lock. This uses most of the rack for one bike, though, so you might not always be able to do this.

    Note that if you secure your rear wheel inside the rear triangle, as shown above, you are securing the frame automatically since the wheel can't be separated from the frame.

    Ignoring the inside of the rack and using the end as a simple post also works well, as shown below, where frame and front wheel are locked with a cable and the rear wheel with a U-lock. There are only 2 ends per rack, though, and they fill up fast in heavily-used locations, so try to show up early to get one of these spaces.


    • Toast racks

      These look similar to the racks used for cooling toast. The photo below shows the intended use for these racks, which again only allows the front wheel to be locked unless you have a very long cable.

      Putting the bike in "backwards" works much better, as shown below, allowing frame and front wheel to be locked with a more normal length of cable.

      Even better is to ignore the wheel slot completely, and roll the bike so that the seat tube is near to the high point of the wheel slot. The photo below shows the front wheel and the frame locked to the rack with a cable and the rear wheel (and the frame) locked to the rack with a U-lock. You need room on both sides of the rack to do this and you don't always have that. Also, some toast racks have a horizontal bar across the top, and you have to lift your bike over that to get it in backwards. Still, with some ingenuity and extra space you can usually make it work. Proper positioning of the pedals makes it easier.


    • Posts

      A simple vertical post such as a parking meter, small tree or porch column can serve if there is no rack available or if the racks are full. Be sure to pick one that doesn't allow the bike and lock to be lifted up and slid off the top. Only very skinny posts allow the use of U-locks, but a cable lock works with all sizes. Be sure to go all the way around and through both wheels. Position the pedals properly to get the bike as close to the post as you can to make it easier. The support post of a chain link fence is better than the fence itself, since the fencing material is much easier to cut than a bike lock or the post.

      This is a bad choice of posts. The bike can be slid off the top, and you might get in trouble for blocking a fire hydrant.

      This is a good choice of posts, although the fence support behind it might be even better, since it is skinny enough that a U-lock might fit.

  • Other tips and tricks

    If you are absolutely unable to lock both your wheels, you may want to make your wheels harder to remove by using locking skewers. These have a removable lever that acts as a key, and the wheels can't be removed with normal tools.

    Bike seats with quick release clamps can be easily stolen. If you don't need to adjust your seat frequently, and most people don't, you can replace the quick release with a fixed bolt. If you want to keep the quick release, there are several locking mechanisms available to keep your seat from being stolen. You can also pull it out yourself and either take it with you or thread your cable through the seat rails and lock it along with your bike (this isn't' possible with some combinations of saddles and cables). Use a piece of tape on the seat post so you can easily get it back to the same height. You can lock your helmet the same way, threading the cable through the straps, if you don't want to take it with you.

    License and/or register your bike. Most states have optional licensing programs, although there are places, such as Stanford University, where licensing is required. There are also private bicycle registry programs. These don't prevent your bike from being stolen, but they greatly increase your chances of recovering a stolen bike. There are also insurance programs offered by the major lock manufacturers.

  • More information

    • Click here to get a printable, one-page PDF file that is a short version of the information above, aimed at bike parking at schools.

    • Click here for the Wikipedia entry on bike locks

    • Click here for bicycle theft information from Bicycle Source

    • Click here for Jim Langley's advice on How to Lock a Bicycle

    • Click here for bike locking information from Sheldon Brown

    • Click here for bike locking information from the Missing Link Bike Co-op

    • Click here for information on bike locks from "Why Cycle"

    • Click here for information on the National Bike Registry

    • Click here for the bike parking guidelines from the Association of Pedestrian and Bicycle Professionals

    • Click here for Chapter 10, the bike parking chapter, of the VTA Bicycle Technical Guidelines


For more information, send email to , or call Rich Swent at (650) 493-7979