If you’re trying to buy a new bike lock, but can’t wrap your head around the fancy materials and measurements, don’t panic!
I understand exactly how confusing buying a new lock can be. Thousands of different locks to choose from, different designs, different prices, but most importantly different quality materials.
This leaves us with two questions:
- What bike locks made from?
- Which bike lock type works best for me?
Fortunately, you’ve come to the right place.
By the end of this article, you’ll know what different types of bike locks are made from, and you’ll have a better understanding of which locks are suitable for you and your bike!
What Are Bike Locks Made From?
The easiest way to answer the above question is to break the bike locks down into their different types.
The majority of bike locks are constructed from hardened steel. Hardened steel provides increased resistance against cutting, cropping and abrasion when compared to mild steel.
That being said there are many different elements that steel is alloyed with, keep reading and I’ll explain the benefits the different alloys provide.
Below I explain the materials that all of the different types of bike lock are made from. I also include plenty of helpful information on how you can secure your bike with each lock type and cover each lock type’s vulnerabilities.
If you know the type of lock you want to learn about, use the buttons below for quick navigation.
What to Look For When Buying a Bike Lock
When purchasing any bike lock, the three most important aspects you should consider are:
You should choose a lock that works well with your bike. For example if you’ve invested a large amount of money into your bicycle, you’ll want a D lock that’s super secure.
The rule of thumb you can follow with locks is “the thicker the shackle, the stronger the lock”
If you’re shopping for a new bike lock and want a more detailed look at each lock type and their features, read this in-depth guide before continuing with this article.
Bike D Locks (U Locks)
Bike D locks, commonly referred to as U locks, are the most popular type of bike lock. These locks get their name from their D/U shape and provide a well-rounded approach to bicycle security.
A D lock can be used to secure your bike in a variety of ways. Normally, a D lock will be used to lock your bike’s frame to an immovable object, but you can also secure accessories and other components with a D lock.
D locks are normally designed to secure one bike. However, larger versions of some models are available that can safely lock two bicycles.
What Are Bike D Locks (U Locks) Made From?
Virtually all bicycle D locks are made from hardened steel. Hardened steel is a type of mid to high carbon steel which has been put through several hardening processes.
The regular hardening process for steel involves heat treatment, quenching and further reheating.
There are several different types of carbon steel available, later in the article, I’ll explain exactly what these are and what they’re used for.
Most manufacturers use hardened steel for their D locks because it provides increased resistance to methods thieves use to defeat locks; cutting, twisting, hammering etc.
Hardened steel is also more resistant to corrosion, increasing the lifespan of locks it’s used with.
How Effective Are D Locks (U Locks)?
D locks are an all-rounder when it comes to bicycle security.
These locks are portable, provide great protection for your bike, and as we found out in my review of the best cheap bike locks, they can be bought for very reasonable prices!
Bear in mind that whilst high-security cheap D locks are available on the market, these are unlikely to last as long as a more premium D lock.
Cheaper D locks tend to use more plastic, which can become brittle over time and break. More premium D locks will use minimal plastic or higher quality plastics that are durable and will last longer.
What to Look for When Buying a D Lock
As you’ll have read, it’s important to choose a bike lock that’s suited to your bike.
For expensive bikes, you’ll want a D lock that offers increased security. The most secure D locks will have a Sold Secure Gold or Diamond rating and will normally have a hardened steel shackle with a diameter of at least 16mm.
Thicker D locks offer more security for your bike but will weigh more, so aren’t as portable. Therefore, if your bike didn’t cost much, you might decide to go for a lightweight D lock that’s easier to transport.
This image displays how important lock size is, but also that D locks aren’t necessarily the best option when it comes to bike locks. If you need a more versatile lock, I cover folding locks and chain locks below.
When locking your bike with a D lock, it’s important to fill the shackle and keep it away from the ground where possible.
If you’re locking multiple bikes, you’ll want a lock that offers more space inside the shackle. Whereas, if you’re only locking one bike, a D lock with less shackle space will work well.
Recommended D Locks (U Locks)
The D locks below are several of the top-performing locks from reviews I’ve put together.
They provide slightly different qualities and features (highlighted below) but will all provide a very respectable level of protection for your bike.
If you’re looking for a suitable D lock, read my in-depth guide of the best D locks on the market.
(8.3cm x 15.3cm)
(11.5cm x 20.2cm)
(11.1cm x 24.5cm)
(8.3cm x 15.3cm)
(11.5cm x 20.2cm)
(11.1cm x 24.5cm)
Last update on 2023-05-29 at 05:50 / Affiliate links / Images from Amazon Product Advertising API
Bike Chain Locks
Chain locks are another popular type of bike lock, which provide plenty of locking options and can easily secure multiple bikes.
Bike chain locks are commonly used in bike sheds and garages as stationary locks. Due to their increased weight and size, bike chain locks aren’t as portable as D locks.
What Are Bike Chain Locks Made From?
Similarly to D locks, bike chains tend to be made from hardened steel. Many different alloying elements are used with bike chains, from boron to manganese.
Pragmasis offer one of the strongest ranges of chain locks on the market, the Protector Chains. These chains are made from Boron steel, which is commonly used in security products as it provides excellent resistance to hacksaws, bolt cutters and hammer attacks.
OnGuard offer the OnGuard Mastiff 8019 chains which are titanium-reinforced hardened steel. Titanium nitride is applied as a thin coating to the outside of the hardened steel chain.
Titanium reinforcing is often used with machine parts and drill bits as it increases their durability by up to three times compared to non reinforced parts.
There are many other hardening procedures used when creating hardened steel. The methods of hardening used above produce a stronger, more durable bike chain lock.
Normally bike chain locks have an outer sheath that prevents them from scratching or damaging your bike. This sleeve will also keep your chain clean and tends to be made from nylon, although some high-quality chain covers are made from neoprene.
How Effective Are Chain Locks?
As I described above, bike chain locks are used for various reasons, the most popular being the need to secure multiple bikes.
D locks have a rigid metal shackle which may sometimes struggle when locking your bike to larger immovable objects (e.g. street lights). Chain locks are made from multiple metal links which are joined together and allow it to lock your bike to almost any object.
Chain links with a diameter of 16mm or more are considered bolt cutter proof and are virtually impossible to defeat with anything other than power tools.
Whilst a 16mm chain sounds ideal, you’d struggle to carry one with you whilst cycling, making them a better static locking option that you use to lock your bike at home.
There are several smaller chains that can be considered portable, just remember that thinner links will ultimately result in a lower level of security for your bike.
When locking your bike with a chain lock, keep it away from the ground and make sure to utilise its full length. This will make it considerably harder for thieves to defeat.
What to Look for When Buying a Chain Lock
As always, when buying any bike lock, make sure to look out for Sold Secure ratings, or other security ratings such as ART.
I don’t recommend locks that bear the Sold Secure Bronze rating (unless used to secure accessories) as they only provide protection against opportunist thieves.
If you’re looking for a portable chain lock you’ll probably want to look for a lock with 10-12mm links. These won’t be too heavy to carry, but will still provide a good level of protection for your bike.
The Kryptonite 1055 Mini uses 10mm 3T hardened manganese steel and offers Sold Secure Gold rated security.
Recommended Chain Locks
I’ve used and reviewed all three of these chain locks. They have different intended uses with some being suitable for portable use whilst others are stationary chains.
The information in the table below can be used to help you decide if any of these chains are suitable for you.
If you’d like to view a wider variety of suggestions, check out my review of the 15 best chain locks!
Last update on 2023-05-28 at 23:10 / Affiliate links / Images from Amazon Product Advertising API
Folding Bike Locks
Folding bike locks are a newly emerging breed of bike lock that combine the strength of a D lock with the flexibility of a chain lock.
Folding bike locks are some of the most versatile locks on the market. But what are folding bike locks made from? Let’s find out.
What Are Folding Bike Locks Made From?
The majority of Folding bike locks are made from hardened steel. You’ve probably spotted the trend here!
Hardened steel alloys are the go-to when it comes to bike locks as they provide great tensile strength and impressive resistance to repeated impact attacks.
The ABUS Bordo 6500, one of the best folding bike locks, uses several 5.5mm plates made from a “specially hardened steel”.
Similarly, the equally secure, Sold Secure Gold rated Trelock FS 500 uses 5.5mm plates made of “hardened steel”.
Kryptonite don’t have a Sold Secure rated folding bike lock, but their most secure folding lock also uses hardened steel plates, except they’re slightly thinner at 5mm.
The majority of folding locks have a soft outer rubber casing which prevents the hardened metal inside from ruining your bike’s paintwork.
How Effective Are Folding Locks?
If you need a portable, high-security bike lock, there may be no better option than a folding bike lock.
I wouldn’t go as far as saying that folding locks offer the same security as D locks, they use thinner plates which are more vulnerable to bolt cutters.
However, as covered above, several folding locks offer the Sold Secure Gold rating.
Folding bike locks are also lightweight and tend to weigh 1-1.5kg (2.2-3.3lb) which means they’re easy to transport and won’t weigh you down.
Similarly to chain locks, the flexible shackle a folding lock uses allows them to bend and flex around larger immovable objects.
What to Look for When Buying a Folding Bike Lock
Brands produce folding locks with different features, some implement anti-theft alarms, some use smart keyless locking, and others keep it nice and simple.
As always, when shopping for a new bike lock a good way to guarantee you’re buying a quality lock is to look out for Sold Secure ratings.
Currently, the highest rating a folding lock has received is the Sold Secure Gold rating. The Gold rating folding bike locks use 5.5mm hardened steel plates, so if security is paramount, keep an eye out for 5.5mm plates or thicker!
Otherwise, another feature that varies with folding locks is the mounting systems they’re supplied with. Some mounting systems are better than others. If you’re interested, read about the best folding bike locks.
Recommended Folding Locks
I’ve had extensive hands-on experience with all of the best folding bike locks. Below I’ve included my two favourites.
The table displays their different features and other key information. If you want a more secure yet portable lock, a D lock would be a good alternative.
(22.6cm x 10cm)
(26cm x 12.5cm)
(22.6cm x 10cm)
(26cm x 12.5cm)
Last update on 2023-05-29 at 03:20 / Affiliate links / Images from Amazon Product Advertising API
Bike Cable Locks
For a type of bike lock that offers very minimal security, cable locks are much more popular than you’d think.
I would never advise the use of a cable lock as your primary bike lock. The majority of cable locks can be compromised with a small pair of hand pliers and aren’t worth your time.
So why are cable locks so popular, what are they suitable for, and what are bike cable locks made from?
What Are Bike Cable Locks Made From?
Bike cable locks are made from a number of thin metal cables braided or wound together to create one stronger cable.
The majority of cable locks are made from steel cables. Unlike the other lock types we’ve looked at, bike cable locks aren’t made with hardened steel.
Instead, they use low carbon or mild steel cables. This means that when braided together, the end product remains ductile and flexible.
How Effective Are Cable Locks?
Because bike cable locks are made from mild steel there able to flex and secure your bike to larger objects.
Cable lock offer increased versatility compared to D locks, and they also provide an increased number of locking options.
Bear in mind, however, D locks offer massively improved security compared to cable locks, which is evident from the lack of Sold Secure approved cable locks.
Instead of using a cable lock as your primary bike lock, use one to secure your accessories such as your saddle or wheels whilst locking up.
If you’d like to learn more about different bike cable locks, I reviewed three of the best cable extensions here.
What to Look For When Buying a Cable Lock?
When looking for a cable lock, it’s important to consider the length of the cable and what you’ll be using it to secure.
Also, consider whether you want a cable extension to be used in conjunction with a more secure lock or a cable with its own integrated locking system.
A longer cable such as the Kryptonite Kryptoflex 710 is capable of securing your front wheel and saddle whilst your primary bike lock safely secures the frame and rear wheel of your bike.
Shorter cables such as the ABUS Numero 5510C [Amazon] can easily be carried in a backpack. This cable also coils away so that it takes up minimal space.
Just remember, cable locks can be cut in a matter of seconds or even defeated by hand!
Recommended Cable Locks
Of all of the cable locks out there I personally like to use cable extensions. Using a cable alongside your main bike lock will further deter chancers and opportunist thieves.
Last update on 2023-05-29 at 03:20 / Affiliate links / Images from Amazon Product Advertising API
Alternative Bike Locks
What Is the Litelok Made From?
The LiteLok is an innovative new style of bike lock which uses its own patented material, Boaflexicore.
Amazingly, this new material has self healing properties. If a cut is made into the LiteLok, Boaflexicore expands into the cut and puts more material in the way of the cutting tool.
The LiteLok also uses a number of steel cables inside that add to the security that this lock offers. The LiteLok Gold bears the Sold Secure Gold rating.
What Is the TiGr Mini Made From?
The TiGr Mini is another alternative bike lock. The scientists of you may have realised that the TiGr is constructed from titanium, which makes it a super lightweight bike lock.
The TiGr weighs 0.4kg (0.9lb) which makes it one of the lightest bike locks on the market, but how does titanium hold up when used to build bike locks?
Titanium offers an incredible strength to weight ratio and outperforms hardened steel in more than one category.
To learn more about the TiGr, read this review.
Why Are Most Bike Locks Made From Hardend Steel?
If you’ve read the above, you’ll have realised that almost all bike locks are made from a hardened steel alloy.
I wanted to look a little further into why hardened steel is the most popular choice and so below you’ll find the qualities and characteristics of hardened steel.
Have a read, to find out why this is the most common material used to create bike locks.
After being put through its hardening process, hardened steel is more resistant to wear and can withstand rough usage and repetitive heavy impacts.
This makes hardened steel a perfect candidate for bike locks.
Hardened steel benefits from greatly increased corrosion resistance compared to mild steel.
The hardening process makes the steel resistant to corrosive chemicals, and atmospheric corrosion.
Many manufacturers add an additional anti-corrosive layer to their hardened steel products.
Hardened Steel is capable of withstanding repeated heavy abrasion.
This makes hardened steel much better than mild steel as it will provide resistance to sawing, increasing the security bike locks offer.
Research conducted states that heat-treated steel is twice as durable as untreated steel. 
Summary – What Are Bike Locks Made Of
Hopefully this article has helped you understand what different types of bike locks are made of.
You should have also picked up what each type of bike lock is suitable for as well as their strengths and weaknesses.
If you’re still not sure which type of bike lock is suitable for you, my bike lock buying guide will point you in the right direction.
Using two different locks is probably the best deterrent you can utilise. This will drastically increase the time it takes for a thief to steal your bike.
Otherwise, if you now know what type of bike lock you need, navigate to your preferred lock type below, for several top-quality affordable suggestions.
As always, lock it or lose it. Ciao for now!
 Publication – Steel Heat Treatment: Equipment and Process Design