Our pick
Kryptonite New-U Evolution Mini-7 With Double Loop Cable
With a dual-locking hardened 13 mm shackle, an included cable, and a free year of anti-theft protection, the Kryptonite New-U Evolution Mini-7 is a good deterrent at a reasonable price.
Buying Options
*At the time of publishing, the price was $73.
The Kryptonite New-U Evolution Mini-7 should withstand attacks from everything but power tools under most circumstances. Once our testing began, we immediately saw the huge advantage this lock had over the competition: Its 13-millimeter hardened shackle (the big U-shaped loop that gives U-locks their name) can withstand bolt cutters, eliminating a large percentage of potential thieves. Measuring 7 inches long and weighing a little under 3 pounds, it’s the perfect size for most people—long enough to lock the wheel and frame of most bicycles to a rack while leaving almost no room for someone to wedge a pry bar or a car jack inside it. On top of that, the shackle in this design has an additional cutout at the end, which makes rotating (and therefore removing) it after cutting it even more difficult. The New-U Evolution Mini-7 uses a disc-detainer locking mechanism, which is much harder to pick than a typical wafer lock and should foil all but the most savvy criminal using specialty tools. It also comes with a 4-foot cable to secure the front wheel, plus a free year of Kryptonite’s anti-theft protection. Two caveats on the latter: You must register your lock within 30 days of buying it, and the anti-theft protection on this lock does not apply to residents of Manhattan, where theft is very high. (The company’s New York lock series—including our upgrade pick and the chain pick below—is covered even in Manhattan.)
Upgrade pick
With an 18 mm dual-locking hardened shackle, the Kryptonite New-U New York Fahgettaboudit Mini held up better than any other lock against cutting attacks. Even with a powered cut-off wheel, our testers took over a minute to make the two cuts necessary to remove it—four times longer to grind through than with the New-U Evolution Mini-7. However, this lock doesn’t come with a cable, and it weighs almost 4.5 pounds, a full pound and a half more than the Mini-7. But if you’re in a high-risk area, this lock is the one to buy. Like our top pick, it uses a very secure disc-detainer mechanism, and it’s long enough to fit around your bike’s frame and your wheel without becoming too cumbersome. For extra peace of mind, it also comes with a free year of the highest level of anti-theft coverage from Kryptonite. (Again, you have to register your lock within 30 days of purchase for the coverage to take effect.)
Also great
Kryptonite New York Fahgettaboudit Chain
If you need more length in your lock and weight is of little concern, the 10-pound Fahgettaboudit Chain is really tough.
Buying Options
*At the time of publishing, the price was $170.
If you want to secure more than just your bike frame and wheel, if you have a cargo or electric bike that needs a longer lock, or if your favorite spot to lock up is around a street post, go with the Kryptonite New York Fahgettaboudit Chain, which is one of the toughest chain locks we tested. We encountered other chain locks that were harder to cut through, but they either cost more or weighed more. It has 3 feet of 14 mm hardened links held together by a 15 mm Kryptonite New York Disc Lock, and it should keep all but the most determined thieves at bay.
Also great
Kryptonite Keeper 585
This relatively lightweight folding lock can wrap around odd angles more easily than a U-lock and is more secure than a cable lock—but it’s not nearly as strong as a chain, and it’s pricey, too.
Buying Options
*At the time of publishing, the price was $65.
If security is your only concern, we recommend skipping a folding lock altogether because the rivets are easy to break. But there are a few special requirements that folding locks can accommodate that other options can’t: You can lock them around large or strange shapes like handrails or lamp posts, they’re much sturdier than cables, and they’re a lot lighter than chains (and a pound lighter than our top U-lock pick, even minus its cable). We believe the Kryptonite Keeper 585 offers the best combination of security, weight, and price among folding locks. It also comes in a longer, 100 cm (39-inch) version, the Keeper 510.
The Keeper 585 measures 85 cm (32 inches) long, weighs 1.7 pounds, has 3 mm hardened steel rivets, and comes with $500 of anti-theft protection from Kryptonite. Is your bike worth thousands more than $500? That should tell you everything you need to know—get a stronger lock.