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When it comes to protecting your bike against would-be thieves, it doesn’t get much better than the U-lock. Though they’re technically just a padlock with longer shackles, U-locks excel in bike safety where smaller padlocks can’t; with U-locks, you can protect your bicycle’s frame by directly securing it to a post or rack rather than feeding a fragile cable lock or chain through your bike’s wheels. U-locks are tougher and harder to beat with most hand tools, and thieves will have a more annoying time when trying to cut through one versus something smaller.
If you’re looking for a smart way to secure your bicycle, reach for a U-lock that’s lightweight, made of hardened steel, and features double deadbolts. Need that protection in a jiffy? Consider grabbing one of these durable U-locks from Amazon for some safety that’ll ship fast
The Best U-Locks for Bicycles
1
Best Overall
Kryptonite New York Standard Heavy Duty Bicycle U-Lock
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2
3
4
5
Best Heavy-Duty
Altor Locks SAF Angle Grinder Proof Bicycle U-Lock
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6
7
What to Consider
A reliable U-lock—also known as a D-lock in the U.K.—is fairly heavy and durable, and usually is made of hardened steel. Reach for U-locks that have double deadbolts, which lock the shackle into both ends of its crossbar, forcing thieves to make two cuts instead of one. You should always lock your bike by the inside of its rear triangle, halting the back wheel from movement and thus preventing someone from trying to remove it. Buying a second U-lock isn't a bad idea either, as you can use it to lock your bike's front wheel and frame together.
How We Evaluated
To find the best U-locks on Amazon, we referenced various competitor websites and message boards to find the most frequently recommended products in regards to safety, weight, durability, and value. We also consulted our own gear-testing guide to the best bike locks and made mention of various U-locks found there, such as the Kryptonite New York Standard and the Hiplok Spin. We prioritized listing products that have double deadbolt designs, as well as those that Amazon reviewers cited as being tough to break or cut by way of twisting and other physical attacks on hardware. Finally, we sifted through numerous expert reviews and Amazon buyer reviews to bring you the U-locks you'll find below, all of which have average user ratings of 4 out of 5 stars or higher.
Looking for more bike protection? Check out our picks for the best helmets, headlights, and padlocks.
1
Best Overall
Kryptonite New York Standard Heavy Duty Bicycle U-Lock
1
Best Overall
Kryptonite New York Standard Heavy Duty Bicycle U-Lock
Pros
- Lightweight
- Very durable
- Amazing warranty offer
Cons
- Flimsy mounting bracket
We’ve tested a wide range of locks on the market and evaluated them by cutting, weighing, and using them in a variety of situations. In our opinion, this lock by Kryptonite rules supreme.
This four-pound U-lock is made with a hardened steel shackle with a pass-through crossbar design, which prevents twisting and single-cut-style attacks, thus forcing thieves to cut through the shackle twice to break it. Each end of this U-lock deadbolts shut, instead of the typical one-sided mounted shackle, which makes for a better reinforced locking mechanism.
It comes with two keys, one of which has an LED light, and a warranty that guarantees up to $4,000 reimbursem*nt if your Kryptonite lock is compromised and your bike gets stolen. When it comes to bike safety, it doesn’t get much better than this.
Key Specs
| Weight | 4 pounds |
|---|---|
| Shackle Thickness | 16 millimeters |
| Inner Shackle Width | 4 inches |
| Inner Shackle Length | 8 inches |
2
Best Wide Shackle
ONGUARD Brute LS U-Lock
Pros
- Wide shackle for a larger range of lock-up options
- Very durable
- Comes with plenty of spare keys
Cons
- Mounting bracket is flimsy
A wider shackle means more room to lock up around larger objects like light poles and thick railings. This one from OnGuard is one of our favorites. Its U-shaped shackle measures 4.5 inches wide and 10 inches tall, which many users say is wide enough to lock up their adult tricycles.
The keyhole on this hefty lock automatically closes to ward off the elements, while a rubber piece helps protect your frame from scratches. It comes with five keys in total, so it’ll provide some peace of mind in case you lose a few. Users say this lock doesn’t ever jam, even after years of usage. It’s also another favorite of ours.
Key Specs
| Weight | 1.7 pounds |
|---|---|
| Shackle Thickness | 16 millimeters |
| Inner Shackle Width | 4.5 inches |
| Inner Shackle Length | 10 inches |
3
Best Cable and U-Lock Set
ABUS Ultra 410 Bike U-Lock
Pros
- Great set for its price
- Sturdy U-lock
Cons
- Cable isn't tough enough for overnight parking
If you need a U-lock but lack a cable to use it with, check out this option from Abus. This sturdy, double-bolting U-lock has hardened steel for cut and torsion resistance, and its pass-through shackle helps prevent rotating attacks from thieves. Its included steel cable, meanwhile, is just about 4 feet long, providing enough space to lock up a single bike on the go.
Users love this package for its great value and ease of use. While this set offers a convenient price, we don’t recommend its steel cable for overnight parking.
Key Specs
| Weight | 2 pounds |
|---|---|
| Shackle Thickness | 12 millimeters |
| Inner Shackle Width | 4 inches |
| Inner Shackle Length | 9 inches |
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Pros
- Surprisingly durable for its price
- Very affordable
Cons
While cutting the costs on locks may also mean, well, locks that are easily cut, this entry from Bell provides value without sacrificing safety. For about $20, you can grab this 12-millimeter U-lock with a set of two keys. This alloy steel lock is coated in vinyl to prevent frame damage, and it even includes a mounting bracket with quick release for easy transportation. Over 3,100 users get this a 4.5 out of 5-star average rating and praise it for its convenience and value.
Key Specs
| Weight | 2 pounds |
|---|---|
| Shackle Thickness | 12 millimeters |
| Inner Shackle Width | 4.5 inches |
| Inner Shackle Length | 8 inches |
5
Best Heavy-Duty
Altor Locks SAF Angle Grinder Proof Bicycle U-Lock
5
Best Heavy-Duty
Altor Locks SAF Angle Grinder Proof Bicycle U-Lock
Pros
- Incredibly thick shackle
- Extremely durable
Cons
- Very heavy
- Small inner-shackle dimensions
This massive tank of a U-lock is guaranteed to keep your bike safe, all thanks to its shackle casing, made of a whopping 3 inches of hardened steel. While the actual shackle is 14 millimeters, it's protected by 80 millimeters of steel that warns others that no average cutter, crowbar, or hammer will be able to easily penetrate it—and especially not in a hurry. If that kind of thief deterrent interests you, this U-lock might be your messiah.
Do note, however, that because of its thick steel, some of the inner width and length of the shackle are sacrificed for more protection. Though the lock itself is fairly large, you’ll only have about 3 inches of width and 5.5 inches of length for your frame to fit in. This lock is also just as heavy as you’d imagine, weighing 13 pounds, which doesn’t make it as portable as we’d like.
Key Specs
| Weight | 13 pounds |
|---|---|
| Shackle Width | 80 millimeters |
| Inner Shackle Width | 3.2 inches |
| Inner Shackle Length | 5.5 inches |
6
Most Lightweight
OTTOLOCK Sidekick Compact U-Lock
6
Most Lightweight
OTTOLOCK Sidekick Compact U-Lock
Pros
- Super compact design
- Minimalist and simple
- Extremely light
- Lots of color options
Cons
- Small shackle
In search of a lock that won’t weigh down your ride? At just over 1.5 pounds, the Sidekick is so sleek that you’ll forget you’re carrying it. This silicone-coated steel lock has a double-shackle that allows for better protection, plus it’s available in several colors that are so stylish that they’re perfect for showing off on those quick stops over the weekend. It also comes with two keys, so you can stash a spare for safekeeping.
The silicone coating makes it water- and dirt-resistant, though its locking mechanism is open, which exposes it to the elements. Due to its compact design, its inner shackle width and length are fairly small—2.75 inches wide and 5.75 inches long, respectively.
Key Specs
| Weight | 1.7 pounds |
|---|---|
| Shackle Thickness | 12 millimeters |
| Inner Shackle Width | 2.75 inches |
| Inner Shackle Length | 5.75 inches |
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7
Most Stylish
Hiplok DX Wearable Maximum Security U-Lock
Pros
- Easy to carry
- Attractive, bold design
- Compact design
- Lifetime warranty
Cons
Perhaps the most stylish lock on this list, the Hiplok DX models itself after a sort of oversized carabiner—instead of having to mount it to your frame for carrying, you can just clip it onto a belt, bag, or pocket (hence the punny brand name). This lock has a hardened steel body and an anti-twist shackle to prevent most physical attacks, while its colorful, compact design is certainly bold, sleek, and eye-catching.
It comes with three keys in case of loss, and if you register them upon purchase, the company will help you replace them. The lock also offers lifetime protection, should anything happen to it.
Key Specs
| Weight | 2.6 pounds |
|---|---|
| Shackle Thickness | 14 millimeter |
| Inner Shackle Width | 3.3 inches |
| Inner Shackle Length | 6 inches |
Kevin Cortez
Commerce Editor
Kevin Cortez is an editor for Runner's World, Bicycling, and Popular Mechanics covering reviews. A culture and product journalist for over ten years, he’s an expert in men’s style, technology, gaming, coffee, e-bikes, hiking, gear, and all things outdoors. He most recently worked as the Style Editor for Reviewed, a top product recommendation site owned by USA TODAY. He also helped with the launch of WSJ's Buy Side commerce vertical, and has covered the music and podcast industries for Mass Appeal, Genius, Vulture, Leafly, Input, and The A.V. Club. Equally passionate about leisure as he is his penmanship, Kevin dedicates his spare time to graphic novels, birding, making cold brew, and taking long, meandering walks.
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