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#1
Winner
Master Lock 8170D, 6-1/8 inch Wide U-Lock with 8" Shackle, Black
The Master Lock 8170D is a solid choice for anyone needing a tough bike U-lock. Its 1/2 inch (13 mm) thick shackle is made from hardened alloy steel, which offers strong resistance to cutting and prying attempts. This thickness gives good protection for everyday use, especially in moderate-risk areas. The lock uses a key mechanism and includes two keys, making it straightforward to operate but requiring you to keep track of the keys.
Rating
9.9
Chosen by1,225
Security Rating
Size and Weight
Locking Mechanism
Most important from
4759 reviews
#2
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
The Kryptonite Evolution Mini-7 Bike U-Lock is a robust and secure option for cyclists looking to protect their bikes. One of its major strengths is the 13mm hardened steel shackle, which resists bolt cutters and leverage attacks, significantly boosting security. Additionally, the disc-style cylinder is both pick and drill resistant, further enhancing its anti-theft capabilities.
Rating
9.8
Shackle Thickness
Size and Weight
Security Rating
Most important from
13422 reviews
Top 10 Best D Locks 2025 in the United States
#1
Winner
Master Lock 8170D, 6-1/8 inch Wide U-Lock with 8" Shackle, Black
Master Lock 8170D, 6-1/8 inch Wide U-Lock with 8" Shackle, Black
Shackle Thickness: 1/2 inch (13 mm)
Locking Mechanism: Key Lock
Size and Weight: 9.8x7.33x1.33 in, 1.96 lbs
Material: Alloy Steel, Rubber
Mounting Bracket: Included carrier bracket
Chosen by 1225 this week
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
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
Shackle Thickness: 13mm
Locking Mechanism: disc-style cylinder
Size and Weight: 3.25 x 7 inches, 3.55 lbs
Material: Steel
Mounting Bracket: FlexFrame U-bracket
Kryptonite New York Long Shackle Bike U-Lock, Heavy Duty Anti-Theft Security Bicycle Lock Sold Secure Gold, 16mm Long Shackle with Keys, Ultimate Security Lock for Bicycles E-Bikes Scooters
Kryptonite New York Long Shackle Bike U-Lock, Heavy Duty Anti-Theft Security Bicycle Lock Sold Secure Gold, 16mm Long Shackle with Keys, Ultimate Security Lock for Bicycles E-Bikes Scooters
Shackle Thickness: 16mm
Locking Mechanism: Double deadbolt locking
Size and Weight: 4x10.25 inches, 4.85 pounds
Security Rating: 9/10
Material: Alloy Steel
Related Products
Kryptonite New York Standard Bike U-Lock, Heavy Duty Anti-Theft, 16mm Shackle with Mounting Bracket and Keys, Ultimate Security for Bicycles E-Bikes Scooters
Kryptonite New York Standard Bike U-Lock, Heavy Duty Anti-Theft, 16mm Shackle with Mounting Bracket and Keys, Ultimate Security for Bicycles E-Bikes Scooters
Shackle Thickness: 16mm
Locking Mechanism: Deadbolt
Size and Weight: 3.15 x 1.18 x 1.18 inches
Material: Alloy Steel
Mounting Bracket: Yes
Kryptonite New York Fahgettaboutit Mini Bike U-Lock, Heavy Duty Anti-Theft Bicycle U Lock, 18mm Shackle with Keys, Ultimate Security Lock for Bicycles E-Bikes Scooters,Black
Kryptonite New York Fahgettaboutit Mini Bike U-Lock, Heavy Duty Anti-Theft Bicycle U Lock, 18mm Shackle with Keys, Ultimate Security Lock for Bicycles E-Bikes Scooters,Black
Shackle Thickness: 18mm
Locking Mechanism: Double deadbolt
Size and Weight: 9.06 x 5.98 x 1.18 inches, 4.55 lbs
Security Rating: 10/10
Material: Steel
#10
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Buying Guide for the Best D Locks
Choosing the right D-lock for your bike is crucial to ensure its safety and security. D-locks, also known as U-locks, are popular for their strength and resistance to cutting and leverage attacks. When selecting a D-lock, consider the following key specifications to find the best fit for your needs.Shackle ThicknessThe shackle is the U-shaped part of the lock that goes around your bike frame and the object you are locking it to. Thicker shackles are generally more resistant to cutting and prying. Shackle thickness can range from around 12mm to over 18mm. For high-risk areas, a thicker shackle (16mm or more) is recommended, while lower-risk areas might be adequately served by a thinner shackle.
Locking MechanismThe locking mechanism is the part of the lock that secures the shackle in place. There are various types, including key-operated and combination locks. Key-operated locks are generally more secure, but you need to keep track of the key. Combination locks offer convenience as you don't need a key, but they can be less secure. Choose a locking mechanism based on your preference for convenience versus security.
Size and WeightD-locks come in various sizes and weights. Larger locks can secure more of your bike or multiple bikes, but they are heavier and less portable. Smaller locks are lighter and easier to carry but may not fit around larger objects. Consider where and how you will be locking your bike to determine the right balance between size and portability.
Security RatingMany D-locks come with a security rating provided by independent testing organizations. These ratings can help you gauge the lock's effectiveness against theft. Higher ratings indicate better security. If you live in a high-theft area or leave your bike unattended for long periods, opt for a lock with a higher security rating.
MaterialThe material of the lock, usually hardened steel, affects its durability and resistance to attacks. Hardened steel is the most common and effective material, but some locks may use other materials or coatings to enhance strength. Ensure the lock is made from high-quality materials to provide the best protection for your bike.
Mounting BracketA mounting bracket allows you to attach the lock to your bike frame when not in use, making it easier to carry. Not all D-locks come with a mounting bracket, so if portability is important to you, look for a lock that includes one. This feature can be particularly useful for daily commuters.