Master Lock 8170D, 6-1/8 inch Wide U-Lock with 8" Shackle, Black

Absolutely love this lock, the thickness gives me ease of mind. Quality is tip top especially for the price you pay for it. Comes with keys and holder for your bike that you can install. The bar unlocks from both sides making it very easy to install and unlock your bike from racks.

Good deal for a master lock product is always a safe bet. Like literally never bought a bad master lock product that just doesn’t happen as a general rule of thumb. I feel like this will do better for safety against theft then just a regular wired bike locks are easy to cut through for thieves.

This U-Lock came with a mounting bracket as-well, which was able to be used on the handlebars of my electric scooter. It’s not too heavy and comes with a pair of keys attached. It seems pretty solid, and so far hasn’t made much noise when moved! The U-bar has just enough space where it can accommodate a bike rack of many sizes.

Strong, Reliable, and Perfect for Everyday Bike Security This Master Lock U-Lock with the 4-foot cable is one of those dependable tools that just works as advertised. I’ve been using it for both my e-bike and a standard mountain bike, and it gives a solid sense of security without being overly heavy or bulky. The steel shackle feels tough, and the lock engages cleanly every time. The included cable is a nice touch—it allows you to loop through the front wheel or seat so you’re not leaving easy targets for opportunistic theft. The keys fit snugly, and the locking mechanism operates smoothly without any jamming, even after exposure to morning dew and coastal humidity. The included mounting bracket makes it easy to keep on the bike frame for quick access, and the lock’s size is just right for most bike racks and poles. While this isn’t meant to stop a professional with power tools, for everyday use—like parking at cafes, parks, or college campuses—it offers a great balance of strength, convenience, and price. Bottom line: A sturdy, well-designed lock-and-cable combo that provides trustworthy protection for daily riders at a very fair price.

Perfect lock! Works great, easy to unlock and very sturdy! Will fit both big and small tires or any part of your bike, or whatever you would like to lock up.

The lock works great. Real easy to use.

The Master Lock Black Bike Lock has been a total lifesaver for my scooter over the past year—never once failed! A couple of friends relied on wire locks, and sadly, their scooters didn’t make it. This U-lock feels rock-solid and durable, wrapping around the scooter with ease and zero struggle. It even survived a cross-country shipping adventure in the same box as the scooter, picking up some scratches along the way but still holding strong. Keys were occasionally forgotten (oops!), but the backup key saved the day more than once. The only minor quirk is that the key can be a bit finicky at times, but honestly, it’s barely noticeable compared to the peace of mind this lock provides.

Someone stole my hose reel so I bought this to lock it to the water pipe, needless to say I still have my hose reel this is heavy duty and realiable

The Master Lock Black Bike Lock with Key impressed me with its solid construction and sense of security. The lock's quality was apparent from the first use. While I haven't had the unfortunate need to test it against actual theft attempts, I felt confident in its ability to deter thieves. The lock felt very sturdy, and I often tried to pull it apart with my hands to test its strength, finding it very resistant to force. The lock features an integrated disk keyed locking mechanism, which was straightforward to use, though I'm not entirely familiar with the technical details of this mechanism. However, each time I used the lock, it required a bit of effort to lock and unlock efficiently. This could be due to the lock's solid construction, which, while providing security, also made it slightly cumbersome to operate. The description mentioned a vinyl coating, which I'm not entirely sure about in terms of its function or appearance. However, the lock looks well-made and durable. Its weight is significant, which is a positive aspect in terms of security but made it inconvenient to carry in a backpack. Instead, I opted to hang it on my bike during rides, avoiding additional weight on my back, which could affect my riding comfort and speed. Overall, this lock represents a good investment, particularly compared to cheaper alternatives I've used in the past, such as those from Dollarama. It offers a higher level of security and build quality, making it a valuable addition to my biking gear.

prima schloss...funktioniert gut.

Practico y economico, funcional y seguro

For this price this is a great lock, I have been using it for a few years in the city and have had no thefts or issues with the lock. It is a bit heavy but this is to be expected for a metal lock.

Does what it's advertised to do. Not stopping a determined thief, just slowing em down.