The 9 Best U-Locks
Updated by · How we research
Nine bike U-locks compared on security grade, weight, fit and warranty, from city-grade steel to backups. Kryptonite's Evolution Mini-7 leads for commuters. When users buy our independently chosen editorial selections, we may earn commissions to help fund the Wiki.
A thief with a cordless angle grinder can cut almost any steel U-lock in under a minute, so a good lock's real job is to make your bike slower and noisier to steal than the one beside it. These picks suit commuters, students and city riders, from light Diamond-graded locks to cheap backups for quick stops.
At a Glance
Editor's Notes
November 1, 2026, by Ezvid Wiki Admin:
The Kryptonite Evolution Mini-7 takes over the top spot. It holds a Gold security grade, weighs little for that grade, and arrives with a cable, a frame bracket and a lifetime warranty, which covers what most commuters need. The Seatylock Mason 180 is new, for riders who want the Diamond grade without hauling a heavy lock, and the Kryptonite Parkview joins as a cheap backup.
Six locks from the old list stay: the New York Fahgettaboudit (now sold in its Mini size), the OnGuard Bulldog and Pitbull, the ABUS Granit X-Plus 540, the KryptoLok and the Via Velo, which now carries a Bronze grade. The Abus U-Mini 40 is gone because it no longer ships to the U.S. The page covers rigid bike U-locks only, not chains, cables or smart padlocks.
The deciding evidence was OutdoorGearLab's bench test, which timed a corded grinder against each lock and tried bolt cutters and a hacksaw, along with Sold Secure's published grade definitions, Kryptonite's and Seatylock's warranty terms, and U.S. recall records, which list no bike lock recalls for any brand here.
April 06, 2020:
One of a U-lock's major benefits is that it can significantly reduce the amount of available space between itself and the object to which it is secured (e.g. a bike post), making it difficult for a would-be thief to pry the lock open with the blunt force of a crow bar, pry bar, or some other tool. Yes, I've actually witnessed a thief use a pry bar to try and steal a bike. Keep in mind that people drawn to committing acts of theft are pretty resourceful. When criminals are determined and/or desperate, they'll try almost anything to get what they want. But these devices can slow down their progress and, at best, prevent a loss.
While the majority of U-locks look similar at first glance, our list is representative of the fact that they're available in a range of thicknesses and lengths to accommodate bikes of all sizes. While not all of them will offer the high-tech "flair" that some of their smart counterparts are designed to do, we've included the ISmartView Padlock as one biometric option available. At the very least, our remaining options are reliable deterrents that will make your ride harder to steal. Furthermore, we've paid close attention to the materials from which these U-locks are constructed, the keys they utilize, and the types of attacks they're designed to withstand.
The Kryptonite New York Fahgettaboutit has been substituted for its predecessor due to its compact size and double-deadbolt design, making it perfect for use in heavily-traveled metropolitan areas. Many of our other options utilize this same design, like the Via Velo Heavy Duty. Similar to the Kryptonite, one of its keys is equipped with an LED for extra visibility at night. With the double-deadbolt, each end of the device's shackle is secured independently, so if a thief is going to try to break through it, he or she will have to deal with separately-engaging ends, each with its own tamper-resistant grooves that make twist attacks and blunt force impacts more difficult to accomplish in a short period of time. Removing wheels can be a pain, but the OnGuard Bulldog DT is wide enough to secure to most standard meter poles at a single attachment point. This means you don't have to worry about disassembling your ride just to keep it from being lifted.
Special Honors
Bike Index Bike Index is a free, nonprofit bicycle registry. Owners record the make, model and serial number of each bike, and if one is stolen, its record is flagged so shops, buyers and police can check a serial against it. Signing up takes a few minutes and costs nothing. bikeindex.org
Litelok Litelok, a British maker, builds U-locks and D-locks from composite materials meant to resist battery angle grinders, the tool that cuts steel U-locks fastest. In OutdoorGearLab's bench test, its composite lock held out for more than five minutes against a corded grinder. They suit costly bikes and e-bikes parked in high-theft areas. litelok.com
Match The Security Grade To Where You Park
If you insure a costly bike, read the policy: insurers often name a minimum grade.
No steel U-lock stops a thief with a battery angle grinder for long. In OutdoorGearLab's bench test, a corded grinder got through 12 mm to 18 mm hardened U-locks in roughly 12 to 45 seconds, and only composite locks built for that attack held out past five minutes. Its bolt cutters did not beat any of the U-locks it tried. So the goal is to make your bike harder and slower to take than the next one, not to make it theft-proof.
The plainest guide to strength is the Sold Secure grade, set by a British testing house. Bronze is meant for an opportunistic thief and short stops in low-risk places. Silver suits lower-value bikes in medium-risk areas. Gold is aimed at a dedicated thief in big cities and university towns, and Diamond adds power-tool attacks to the test. For an e-bike, look for a Powered Cycle grade; a Diamond pedal-cycle grade counts as Powered Cycle Gold.
Shackle thickness is only part of the story. The steel's hardness, the shape of the bar (square or triangular sections resist cutting better than round ones), whether it bolts at both ends and the quality of the cylinder all count. If you insure a costly bike, read the policy: insurers often name a minimum grade.
Size, Weight And The Cable In The Box
A mini U-lock has an opening a little wider than a frame tube, enough for the frame and one wheel around a post. The small gap leaves a jack or pry bar little room, and the lock is lighter to carry. A standard lock, with an opening about 4 inches wide and 9 inches tall, reaches more rack shapes, thick e-bike tubes and wider posts, but it weighs more and gives a tool more space. OutdoorGearLab and The Best Bike Lock both flag the small opening as the main trade-off of a mini.
Most budget and mid-range kits add a looped steel cable. It's handy for a front wheel, a saddle or a helmet, but a cable can be cut in seconds with hand tools, so it should never be the main lock.
The frame bracket is the part buyers complain about most. Check that it fits your tube before you rely on it, since a small frame may have no room for one; some riders skip it and carry the lock in a bag or a rear rack. Seatylock sells its bracket separately on its U-lock page.
How To Lock A Bike So The Lock Does Its Job
Lock the frame and the rear wheel to something fixed and solid, such as a bolted rack or a thick steel post. Avoid thin sign posts, short poles a thief can lift the bike over, and anything held on with a few bolts. Fill the U as much as you can, so a jack or bar has no room, and keep the keyhole facing down or sideways, away from the ground where grit collects. Remove or lock the front wheel if it's quick-release.
Keep the key number or code card somewhere safe. Kryptonite and Seatylock both tie replacement keys to it, and Seatylock's three-year warranty starts only after key registration. Kryptonite's limited lifetime warranty covers defects, not theft. A drop of lock oil in the cylinder now and then keeps it turning smoothly.
Write down your frame's serial number and register it with Bike Index, a free nonprofit registry police can search. Cutting a lock that isn't yours is a crime, even on your own street; if you lose the keys, call the maker or a locksmith.
How we researched this
We compared 17 U-locks from nine brands, read makers' warranty terms and spec sheets, Sold Secure's grade definitions and OutdoorGearLab's bench test with a grinder, bolt cutters and a hacksaw, analyzed owner feedback, and checked every brand against U.S. Consumer Product Safety Commission recall records.
Sources (11)
Frequently asked questions
Are U-locks the best type of bike lock?
For most riders, yes. A rigid U-lock gives more security for its weight than a chain, folding lock or cable, and a hardened one resists bolt cutters. Chains reach awkward anchors but weigh far more.
Can bolt cutters or a grinder cut a U-lock?
Bolt cutters rarely beat a hardened U-lock. A battery angle grinder can cut almost any steel U-lock in under a minute, but it's loud and draws attention, so most thieves move on to an easier bike.
What do Sold Secure Gold and Diamond mean?
They are grades from Sold Secure, a British testing house. Gold is aimed at a determined thief in cities and university towns. Diamond is the top pedal-cycle grade and includes power-tool attacks.
What's the difference between the OnGuard Pitbull and the Brute?
Both are OnGuard's quad-locking U-locks. The Brute has a thicker, 16.8 mm shackle and weighs more, while the Pitbull uses a 14 mm shackle and is easier to carry. Choose the Brute for high-theft areas.
Is the cable that comes with a U-lock secure?
No. It's for a front wheel, saddle or helmet. A cable can be cut quickly with hand tools, so always run the U-lock through the frame and lock the cable to the U.
Is a regular U-lock enough for an e-bike?
E-bikes are costly and popular with thieves, so use a lock with a Powered Cycle grade, such as Powered Cycle Gold or Diamond, and park in busy, well-lit spots.
