U-lock bike lock MASTERLOCK QUANTUM 8392 green

MASTERLOCK QUANTUM 8392 U-lock in green is a compact, U-shaped bicycle security lock designed to protect a bike frame and wheel by securing them to fixed objects. The lock features a hardened shackle and a keyed cylinder with model-specific keying. Its small footprint makes it suitable for everyday urban use, commuting and short-term parking, and it can be carried on the frame or in a bag.

Advantages

The hardened shackle provides increased resistance to cutting and prying compared with non-hardened designs, while the keyed cylinder delivers reliable key operation and reduces the risk of accidental opening. The compact size balances portability and security, allowing convenient storage on the bike frame or in a backpack. The green finish offers visual identification and corrosion resistance suitable for regular city use.

Suitable for

• Securing a bike to bike racks, posts or railings during short-term stops
• Everyday urban commuting where compact, portable security is required
• Parking at workplaces, shops or public transport hubs for limited durations

Key specifications

• Lock type: U-lock (D-lock) with keyed cylinder
• Shackle: hardened steel construction for cut resistance
• Finish: green protective coating
• Design: compact U-shaped profile for frame and wheel security
• Portability: suitable for carrying on frame mounts or in bags

How to use

Open the keyed cylinder with the supplied key, position the shackle through the bike frame and, when possible, both a wheel and a fixed object such as a rack or post. Close the shackle into the locking body until it engages and remove the key. Ensure the fit leaves minimal free space to reduce leverage points and check that the key turns smoothly to confirm full lock engagement before leaving the bicycle unattended.

Usage recommendations

For improved security, use the lock in combination with additional measures such as securing both wheels with secondary locks or using the U-lock to immobilize the frame and a cable to secure the remaining wheel. Store spare keys safely and inspect the lock periodically for wear or corrosion, lubricating the cylinder as needed with a suitable lock lubricant.