Best U Lock -Reviewed by Experts

Getting lost in a rabbit hole of never-ending research can be simple as you look for the best U lock. To conduct that research for you, we worked tirelessly for weeks. We discovered that a very small percentage broke a quality lock of people after speaking with numerous U lock companies, law enforcement, and thousands of cyclists.

It can be difficult to choose the best U lock for your bicycle. There are many options available. And making the wrong choice can have disastrous results. Choosing the best U lock that is both strong enough to protect your bike and simple enough to use regularly is the key to success. This harmony between power and pragmatism, in my opinion, is crucial. Considering their level of security and my user reviews, I’ve listed the top 10 best U locks below.

Best u lock With Specifications

1. Bell 7067993 Catalyst 300 U Lock, Black

Features :

  • A must on campuses and in high-crime areas
  • 8 inch hardened steel shackle and crossbar for Tough Security
  • Carrying Bracket with Quick release guarantees ease of Transportation
  • Vinyl crossbar and shackle coating Protects bike from scratches
  • 500 anti-theft Protection and 2 keys included

Additional Info :

Color Catalyst 300 – Black
Item Dimensions
Height 3
Width 6
Length 5
Weight 2

2. Master Lock 8170D U-Lock Bike Lock with Key, 1 Pack , 6-1/8 in. Wide , Black

Features :

  • Outdoor heavy duty bike U-lock is best used as a bicycle lock
  • U-shaped steel bike lock with key; Includes carrier bracket for easy transportation
  • Bike lock features a hardened steel body and double locking shackle for superior cutting and prying resistance
  • Bike lock body is 6-1/8 in. (16 cm) wide, with 8 in. (20 cm) shackle length, 4 in. (10 cm) width and 1/2 in. (13 mm) diameter
  • Includes one u-lock bike lock, two keys
  • Affordable U-Lock Protection
  • Disc key for additional anti-pick protection
  • Includes carrier bracket for storage convenience
  • 6-1/8-inch by 8-inchby 4-inch
  • Vinyl coating for weather and scratch resistance

Additional Info :

Color Black
Item Dimensions
Height 1.33
Width 7.33
Length 9.8
Weight 0.25

3. Bike U Lock with Cable – Via Velo Bike Lock Heavy Duty Bicycle U-Lock,14mm Shackle and 10mm x1.8m Cable with Mounting Bracket for Road Bike Mountain Bike Folding Bike

Features :

  • ✔️ DURABLE ALL-WEATHER PROTECTION – Via Velo bike U-lock with hexagonal PVC cover resists corrosion from water, dust and dirt to prolong the life of your lock. All-weather performance means peace of mind and better security
  • ️ ✔️ EASY AND STRONG TO LOCK YOUR BIKE – The bike lock with thickness(including rubber casing):14mm,9.84 in (250mm) x 5.51 in (140mm) U shack to lock and go! Locking your bike and your wheels with 10mm x 180cm cable, fast and easy with our quick, no-hassle system. Great bike safety tool
  • ✔️ AMAZING CONVENIENCE AND SECURITY – 2 keys for convenience! The bike U-lock comes with 2 keys. One of them you can take and use in daily life and the other you can leave at home in case the trouble when you lose one carelessly
  • ✔️ SIMPLY INSTALLING BRACKET ON YOUR BIKE – Convenient high-quality mounting bracket means your lock goes with you, Our bracket is suitable for bike tube:20-42mm. Pls refer to our picture to install the bracket Value for your money
  • ✔️ WARRANTY AND CUSTOMER SERVICE: 3-year warranty applies to U lock for US, CA, UK, EU Cyclists, 90-day money back policy, 24-hour online customer service. If you are not satisfied with it, you get a full refund unconditionally. Rest assured

Additional Info :

Color Black
Item Dimensions
Height 10.236220462
Width 8.0708661335
Length 2.2047244072
Weight 3.0423792156
Release Date 2016-09-19T00:00:01Z

4. SIGTUNA Bike Locks – 16mm Heavy Duty U Lock with U-Lock Shackle and Bicycle Lock Mount Holder + 1200mm Steel Chain Cable Bike Lock

Features :

  • PROTECT YOUR RIDE ✅: This awarded SIGTUNA Bike U-lock is made of 16MM High-Performance Steel for Extensive Holding Power and Resistance against Cut and Leverage attacks with a wapping 85/100 Security Rating. Get the best security available and protect your ride with Sigtuna Locks!
  • CHOOSE POWER ✅: This Bike Lock Combination has a High-Security Disc-Style Cylinder and Double Deadbolt locking mechanism, very effective and certified against Leverage Attacks. With SIGTUNA you make the right choice and give thieves no chance!
  • EASY-TO-USE ✅: This model SIGTUNA Bike Lock Combination comes with a Easy-to-Install Bike Lock Mount, a Protective Coating to protect your bikes paint and not 2, but 3 Laser-Cut Abloy Keys. With this lock you get Security AND Convenience!
  • 100% MONEY-BACK GUARANTEE ✅: If this U-lock is not the favorite you ever owned – some say it is heavy, but that means quality – just send it back and get a 100% refund. SIGTUNA stands for its products. Our customers love that, we know you will too!
  • ORDER YOURS NOW ‎✅: Click “Add to Cart” NOW to get your 16mm SIGTUNA Bike U lock with 1200mm Flex Cable + Mount Bracket tomorrow and give your Bike the Love it deserves.

Additional Info :

Color Yellow
Item Dimensions
Height 1.8897637776
Width 6.9685039299
Length 9.448818888
Weight 3.1

5. USHAKE Bike Combination U Lock, Heavy Duty Bike Combination U Lock Paddle Lock for Bicycle Electric Scooter Motorcycles Metal Fence Gate Anti Theft

Features :

  • 【KEYS-FREE】Bike lock combination for security of your, motorcycle, electric scooter, gate. No more worry for forgetting keys with scooter lock with combination.
  • 【COMBINATION】A strong motorcycle lock with easily setup to your own 4 numbers combo by the fist use. Smooth dials turning gives you confidence for quality.
  • 【STRONG SHACKLE】The bike locks heavy duty anti theft 10 mm hardened zinc alloy shackle resists both cutters and leverage attacks. 4mm PVC coating paddle lock protects the lock from any scratching. Good gate locks for metal fence.
  • 【SOLID CYLINDER & HEAVY DUTY】High security plastic covered cylinder to avoid dust and heavy duty weight (1.25 pounds) U-lock combination for top security of your belongings.
  • 【Customer service】If there is any issues about USHAKE scooter locks anti theft product , please inform us at any time for after sales service and we will follow up closely.

Additional Info :

Color Black
Item Dimensions
Height 8.78
Width 1.02
Length 4.84
Weight 1.2

6. DINOKA Bike U Lock – 16mm Heavy Duty Security U Cable Bike Lock with 4ft Flex Bike Cable and Sturdy Mounting Bracket for Road Bike Mountain Bike Electric Bike Folding Bike

Features :

  • 【Double-opening Head】Our DINOKA heavy duty bicycle u lock is a double-opening head, The thief needs to break the bike locks on both sides at the same time to open it, which is safer than a single-opening head ulock. The lock cylinder of the bicycle is made of C-grade pure copper blades and has a precise structure to prevent various technologies from opening. In addition, the bike u lock is equipped with 2 rust-proof copper keys with a complex snake-shaped slot, which is safer to use.
  • 【Sturdy and Durable】This bicycle lock is made of 16mm/0.63 inch (including 0.1 inches friendly silicone sleeve) hardened high-performance alloy steel, which can resist cutting and lever attacks. Our bike d lock will provide more security for your bike.
  • 【Convenient to Lock】The bike u-lock heavy-duty comes with 4 feet/0.48in steel cable which is coated with PVC covering to provide a greater locking method to protect your bike, suitable for bicycles, motorcycles, electric bike, scooters.
  • 【Portable Size】The size of the u lock for bicycle is 7.9 in * 5.1 in, which is the same size of a 9.7in tablet and is convenient to carry. In addition, come with a mounting bracket that is suitable for all-round tripods with a diameter ≤ of 1.18in (30mm).
  • 【Package Includes】You will get 1*bike ulock, 1*4ft flex cable, 1*mounting bracket and 2*keys, it is very easy to install according to our instructions. If you have any questions, please contact us and we will get back within 24 hours.

Additional Info :

Color White

7. Kryptonite Evolution Mini-7 Bike U-Lock with Cable, Heavy Duty Anti-Theft Bicycle U Lock, 13mm Shackle and 10mm x4ft Length Security Cable with Mounting Bracket and Keys

Features :

  • 3mm Hardened Max Performance Steel Shackle Resists Hand Tools, Bolt Cutters, and Leverage Attacks; 10mm Steel Looped Cable For Additional Security
  • Interior Locking Dimensions: 3.25″ x 7″ Cable Length: 4′
  • Key Safe Program; Kryptonite will ship your first 2 keys for free, globally, in the event you lose them
  • Anti-Theft Protection Offer; Up to $2,500 Reimbursement
  • Includes FLEXFRAME-U BRACKET providing convenient multi-location u-lock transport

Additional Info :

Color Black & Steel
Item Dimensions
Height 7.0078740086
Width 1.181102361
Length 3.2677165321
Weight 2.2

8. Kryptonite Keeper Standard 12mm U-Lock Bicycle Lock with FlexFrame-U Bracket , Black

Features :

  • 12mm Hardened Steel Shackle Resists Hand Tools, Bolt Cutters, and Leverage Attacks
  • Interior Locking Dimensions; 4″ x 8″
  • Key Safe Program; Kryptonite will ship your first 2 keys for free, globally, in the event you lose them.
  • Anti-Theft Protection Offer; Up to $500 Reimbursement
  • Lifetime
  • Sport type: Cycling

Additional Info :

Color Black
Item Dimensions
Height 1.181102361
Width 1.181102361
Length 3.149606296
Weight 2.05
Release Date 2018-01-03T00:00:01Z

9. Bike U Lock,20mm Heavy Duty Combination Bicycle D Lock Shackle 4ft Length Security Cable with Sturdy Mounting Bracket and Key Anti Theft Bicycle Secure Locks

Features :

  • 【Premium Heavy Duty Bike Lock】 This bike D lock comes with a 0.86 inch heavy duty shackle and has excellent heat resistant and hydraulic shear resistant. Equipped with a 0.10 inch silicone cover, it can prevents scratch well and provides excellent safety protection for your bicycle.
  • 【Security and Anti-theft】The bicycle lock is built-in imported c grade pure copper look cylinder, which is certified to resist leverage attacks and provides excellent anti-theft performance, so that your bicycle can be protected with the best safety.
  • 【Easy to Install and Use】The combination bike lock is equipped with a 0.45 inch diameter thick steel cable with a length of 4ft and a high-quality mounting bracket, allowing you to easily install and use it without additional tools. It is very user-friendly.
  • 【Portable and Practical】The bicycle U lock size 7.87 × 6.29 inch, which is lightweight and convenient to carry and store. It is widely used in mountain bicycles, road bicycles, and folding bicycles, providing you with high-quality bicycle safety protection.
  • 【Get Satisfied U Lock Bike Lock】Our combination bike lock set includes bike bock, keys, flex cable and mounting bracket for protecting your bike in all directions. If you have any dissatisfaction with anti theft bicycle lock, please feel free to contact us.

Additional Info :

Color Black
Item Dimensions
Height 1.32
Width 6.29
Length 7.87

10. Kryptonite New-U New York Standard Heavy Duty Bicycle U Lock Bike Lock BLACK/YELLOW, 10

Features :

  • 16mm Hardended Max Performance Steel Shackle Resists Hand Tools, Bolt Cutters, and Leverage Attacks
  • Interior Locking Dimensions; 4″ x 8″
  • Key Safe Program; Kryptonite will ship your first 2 keys for free, globally, in the event you lose them.
  • Anti-Theft Protection Offer; Up to $4,000 Reimbursement for 1 Year Included

Additional Info :

Item Dimensions
Height 1.181102361
Width 1.181102361
Length 3.149606296
Weight 4.40924524

Types of Locking Mechanisms

Manufacturers of bike locks employ a few well-known security-level-varying mechanisms. Anecdotal evidence suggests that destructive attacks are much more common than lock picking, which is an acquired skill. For a master class in advanced bike lock picking, see LockPickingLawyer or Bosnianbill. An expert with the right tools can also open any bike lock fairly quickly. Thankfully, most thieves don’t have specialized tools and aren’t expert locksmiths, but novices can still defeat a few well-known lock designs with easy attacks. To rank the common locking mechanisms from the most to the least secure, we consulted lock-picking expert Schuyler Towne.

Disc Detainer

These locking mechanisms, also known as disc-tumbler locks, work by separating a series of rotating discs with slots with washers. Every disc has a cutout; when locked, the cutouts are out of alignment, but inserting and rotating the key causes them to line up to form a channel. When there is no channel for the lock to drop into, a sidebar rests against the discs and prevents you from turning the lock. This makes picking a disc-detainer lock more challenging than picking other lock designs because it requires aligning each individual disc to a fairly precise position. Because they are relatively secure, don’t contain springs, and can be manufactured with small tolerances, disc-detainer mechanisms are widely used in bike locks. As a result, they continue to function even after many years of use.


When a key is inserted into a slider lock, a set of springless sliders inside a plug that match a slot on the outside of the plug move. A sidebar is supported by the sliders in the slot and must slide into the slot in order for the lock to turn. The sidebar slides into the slot, the plug rotates inside the cylinder when the key is inserted, and the sliders are in the proper positions. These locks can be either high or low security, depending on how they are made and how many sliders there are.

Pin Tumbler

The cylindrical housing of this lock contains a plug. Long pin chambers are present in both the plug and the housing, allowing a number of spring-loaded pins to move back and forth between them. Pins that are in place between the plug and the housing when it is locked prevent the plug from turning. In order for the plug to turn, there must be a space between the spring-loaded pins and the plug or housing when the key is inserted into the plug. These locks can be picked with some skill by depressing each pin individually, but they can also be raked, which takes less skill. When raked quickly across the wafers or pins of a lock, a pick with a specially designed tip known as a “rake” can set them and turn the lock without a key.


This design is typically regarded as the least secure. It is similar to a pin-tumbler lock but uses spring-loaded rectangular wafers rather than pins. These locks are vulnerable to individual pin picking and raking, similar to pin-tumbler locks, but many can be opened using jiggers or model keys, one of which might be close enough to the real key.

How to Choose the Best U Lock Before Buying

To guide you in selecting the best U lock for your bike, there are a few factors to consider before choosing and eventually buying a U lock. Below is a list of items to consider:

Shackle Thickness

Assessing the shackle thickness is the best way to determine the strength of the U lock. A stronger lock typically has a thicker shackle. If its thickness is sufficient, every hand-made tool used to cut the shackle will not harm it. This part of your U lock is also determined by the metal used.

Bolt cutters that can handle medium-sized shackles are most likely to cut through shackles with a thickness of less than 13 mm. The thieves with the largest bolt cutters could probably break the lock and steal your bike if the lock size of your U lock is 13mm to 15mm. It is best to go with U locks with shackle sizes between 16mm and 18mm if you want to be safe from these criminals.

Shackle lock count

A shackle’s lock count plays a role in how strong and vulnerable it is to external threats. In the case of a single bolt lock, the shackle can only be removed from the cylinder once the shackle is cut.

The bike burglar will need more effort to cut twice a double-bolted locking system where the shackle is locked on both sides. As an extreme measure, get a U lock with four shackle locks, like we reviewed previously. Your bike will be protected against outside threats with this lock.


An extra cable is usually added to U locks to provide added protection and safety. As well as the cable’s quality, the U lock’s level of security will be determined by its quality. In general, bikes have light cables that secure other valuable parts. In the end, however, the quality of the material used in making the cable lock will be what determines how well it can protect.

Locking your bike is not only about the cable but also not relying on it. As the primary locking system of your bike, the U lock should still be used. Keeping the cable in your bicycle during a ride can also be inconvenient. Nevertheless, its greatest advantage is to help prevent theft by maximizing its use.


If the bike is to be safe, the lock should have a smaller size than its thickness. In terms of giving the bike thief’s tools space, the smaller, the better. You must make sure that the size is large enough to hold the bike stand and the frame.

Bike Is  Mounts

Bike mounts are a big advantage for bikers. You will be able to bring the U lock on your bike with convenience and comfort. When using a bike mount, the U lock becomes easier to transport.


How do you attach a U lock to a bike?

The best way to fix a U lock to your bike is with a bike mount, which will make it much easier to carry. If you set the mount under the bike seat or on the frame, it will be connected to the post connecting the bike seat. Ensure that it is installed correctly so that it does not disrupt your biking activity.

How do Onguard and Kryptonite U locks compare?

There is no clear winner. There are two brands that produce a variety of bike locks that are reliable and safe for your bike. Keeping up with the times, Kryptonite makes many U-locks, as does Onguard. Both come highly recommended from our team.

What is U lock?

U-locks can be used in many ways to secure your bike. You want to ensure that this type of locking system protects the rear wheel of the bike as well as the frame. Attach it to any other unremovable post such as the bike rack.


You can make your bike more secure by investing in a U-lock. It will ensure that your bike is fully protected. You will have a hard time selecting the right one, but we hope our reviews and recommendations will assist you in making a wise decision.

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