Bicycle Security / Chain Locks vs D Locks

Chain Locks vs D Locks

When you’re not riding your bike, it is unfortunately prone to attack from thieves, whether they’re opportunists looking for an easy target or they’re a little more professional, equipped with tools. So a good quality bike lock is essential when it comes to keeping your bike safe. But what type of lock is best?

Two of the most popular types of bike lock are chain locks and D-locks (or U-locks if you prefer). Some of the most secure bike locks on the market feature within these categories, and we’ll be discussing the benefits of each below.

Some locks are stronger than others

Firstly, whether it’s a chain lock or a D-lock, some locks are stronger than others. This can come down to a variety of reasons, but the thickness of the lock and the materials used are crucial. It stands to reason that a 14mm hardened steel shackle would be harder to break through than a 10mm version, but did you know that the quality of the steel and detail such as the hardening process are also important? These are all factors that the Hiplok Product Team take into account when developing each of our locks.

One of the best ways to check the strength of the lock is to refer to its Sold Secure rating. Sold Secure are an independent testing facility that put locks through a series of real-world tests to determine how easy they are to break. They have four categories for bicycle locks: Bronze, Silver, Gold and Diamond – essentially, a Diamond rated lock is ideal for high-end bicycles and E-bikes and will take significantly longer to break through than a Bronze rated lock. To find out more about Sold Secure and the tests they undertake, check out our Sold Secure Explained blog.

What is a chain lock?

Essentially, a chain lock consists of hardened steel links to create a chain, which is locked together with a padlock or shackle.

What is a D lock?

A D-lock or U-lock consists of a solid piece of metal, called the shackle, which is shaped like the letter ‘U’. There’s also a retaining bar, which locks the shackle in place, so that the lock forms the letter ‘D’.

Benefits of a chain lock

  • A chain lock is usually pretty easy to spot so it will generally deter an opportunist thief merely by being there.
  • The chain links make it quite easy and flexible to use, so you’ll be able to lock your bike to a wider variety of objects. Similarly, you can lock two bikes up fairly easily (assuming you have a long enough chain).
  • A chain lock is usually heavier than a D Lock so is often considered less transportable. However, Hiplok’s wearable chain locks (with our patented wearable design), allow you to carry the lock around your waist, without inhibiting your cycling. In doing so it’s quite easy to forget you’re carrying a lock at all!
  • Chain locks are ideal for home security, particularly when used with a ground or wall anchor, such as the Hiplok ANKR. If it’s a lock you keep at home, you can also consider getting a longer chain (such as the Hiplok HOME) to lock up multiple bikes.

You can check out a few of our wearable chain locks here:

Benefits of a D lock

  • A D-lock is generally smaller and more compact than a chain lock, which means they tend to be lighter to carry.
  • Whilst you don’t have the longer locking length of a chain lock, the compact locking circumference of a D-lock often makes it more difficult for thieves to access with tools.
  • The shackle on a D-lock will usually be thicker than the links on a chain, which make it less susceptible to attacks with bolt croppers.
  • You also get a bit more for your money in terms of security with a D-lock. This simply comes down to the fact that you’re paying for more metal in a chain lock.

Check out some of our D-locks here:

So which is better?

Whilst a D-lock might be slightly lighter than the equivalent chain lock, the Hiplok D-locks and chain locks each feature our Clip + Ride systems, making both styles easy to carry with you. Similarly, a chain lock may offer greater flexibility in terms of what you are able to lock your bike to and how many bikes you’re able to lock up, whereas a D-lock offers a little more security for your money.  

So it comes down to personal choice and may depend on what you’re locking up and where. In some cases, the answer is to use both. Our E-DX for instance is one of the best bike locks for E-bikes and cargo bikes. It features our DX D-lock and a loop chain to provide an extended locking option.

However, the best bike lock is one that you take with you, so whichever lock you decide to choose, it’s better than no lock at all!

Once you’ve decided, check out our security tips for our advice on how to lock your bike correctly.

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