ROCKBROS U Lock and Cable 4 ft Heavy-Duty Bike Lock Kit U Lock and Cable with Mount Bracket, 22mm Shackle

ROCKBROS Bike U Lock Heavy Duty with 4 ft Cable and mounting bracket is a hardened steel U-lock paired with a flexible 1.2 m cable that secures bikes to fixed objects while protecting paint and resisting common cutting tools.

This compact security kit combines a vacuum-heat-treated U-shaped shackle, an anti-tamper lock core, a 4 ft double-loop steel cable and a quick-release frame bracket. Engineered for daily riders, commuters and urban cyclists, the system balances theft resistance with convenient transport and use. The silicone outer cover protects your frame while the included bracket keeps the lock out of the way when you ride.

How does the ROCKBROS U lock resist cutting and tampering?

The U shackle is made from heat-treated steel approximately 22 mm in diameter and tested for toughness to slow or deter common thieves. The lock uses a precise cylinder and a unique key profile designed to make picking and technical opening more difficult. Together these features raise the effort and time required to attack the lock.

• Heat-treated steel shackle (~22 mm) for increased cut resistance
• High-precision lock core with unique key to deter picking
• Protective silicone cover prevents scratches while masking vulnerable edges

What does the included 4 ft cable add to security and flexibility?

The 1.2 m double-looped steel cable extends the reach of the U-lock so you can secure your bike to larger or irregular anchors like poles, fences and signposts. The cable is flexible enough to wrap through wheels or around awkward fixtures yet strong enough to resist forcible removal when paired with the U-lock. Use it when a single rigid shackle cannot reach both the frame and anchor.

• Double-loop ends for easy attachment to the U-lock
• Flexible steel core enables wrapping through frames or wheels
• 1.2 m/4 ft length covers common urban anchoring needs

How easy is it to carry and mount on a bike?

The kit includes a compact mounting bracket sized to hold the U-lock securely on most bike frames, making transport fast and hands-free. The bracket snaps the lock into place for stable riding and quick release when you arrive. The U-lock weighs about 0.8 kg (1.76 lbs), a deliberate trade-off for added protection without excessive bulk.

• Bracket dimensions 21 x 11 cm for convenient frame mounting
• Quick-release bracket design for tool-free access
• Moderate weight (approx. 0.8 kg) balances security and portability

Will this lock scratch my bike or fit different bike types?

The U-lock is finished with a heavy silicone cover that cushions contact points, preventing paint damage and reducing rattling while riding. Its size and shape suit road, mountain, city and electric bikes and it also works for securing gates, scooters and other outdoor equipment. The flexible cable further adapts the system for non-standard anchors.

• Silicone coating protects frame finish and dampens noise
• Compatible with road, mountain, city and e-bike frames
• Also useful for gates, fences and multi-bike anchoring setups

Who is this for: The ROCKBROS Heavy Duty U Lock with 4 ft Cable and bracket is intended for daily commuters, urban cyclists, students and anyone who wants a reliable mid-weight security solution. It’s best for those who need a balance of theft resistance, portability and frame protection—ideal when you lock your bike in public transit hubs, city streets, campuses or mixed-use parking areas.