Best Bike U-Locks of 2026

Six feet of cable is more than any other lock here supplies, and it changes what a lock-up can look like: shackle through the frame and the rack, then the cable through both wheels, or through a friend's bike if you are parking together. The shackle is 18 mm of hardened steel, the thickest in this group, and the kit includes three brass keys and a sliding dust cover.

At the budget end we expected the hardware to be the whole story and the details to be an afterthought, and they are not. The silicone sleeve is thick enough to protect paint, the dust cover stays put rather than flopping open, and the crossbar locks both legs of the shackle instead of one. What is missing is third-party certification, and that is the real gap between this and the Kryptolok.

You pay for the metal at the carry: 3.4 lbs and a bulky body mean a bag is often easier than the bracket, and you will notice it on a long ride. In exchange you get the biggest margin against cutters at this level, three keys rather than two, and a cable long enough that you stop improvising with whatever is at the rack. For a fat-tyre commuter or anyone locking two bikes together, that is a fair swap.

Nine inches of inside length is the reason this lock sits at the top of our list. It is the longest opening in this group, and length is what lets you thread the shackle through the rear wheel and the frame and still close it around a rack with a fat welded sleeve. The 12.7 mm shackle is not the thickest here, but it is hardened steel with a double-deadbolt crossbar, and the lock carries Sold Secure Silver — a tier above the Bronze-rated locks in this group and a step below the SeatyLock Mason's Diamond.

Certification counts for more with us than another millimeter of steel. Sold Secure tests against tools, not adjectives, and the Silver badge is the one line on a lock's listing you can compare honestly across brands. The rest of the kit is unusually complete for the middle of this group: a 10 mm, four-foot double-loop cable that is genuinely worth carrying for the front wheel, two stainless keys, and a disc-style cylinder that is less fussy about grit than the pin-tumbler mechanisms on cheaper locks.

Three and a half pounds is the trade. You feel it on the frame on a long ride, and the FlexFrame-U bracket, while tidy, can creep around the tube over a season — check the bolt, or carry the lock in a bag and forget about it. Against the New York Standard here it is nearly a pound lighter, which for most commuting is the more useful side of the deal.

If your usual rack is a known quantity, the SeatyLock's lower weight and higher rating may suit you better. If you park wherever there is a gap, the extra opening here is worth more than the extra grams, and the cable in the box means you are not buying one separately. Nothing else here covers as many parking situations without asking you to compromise.

This is the lock for the rider who parks an expensive bike in a city and knows it. Sixteen millimeters of hardened steel, shoulders machined to resist the twist-and-cut attack that opens plain U-bolts, and a disc-style cylinder built to shrug off picks and drills. A vinyl coating keeps it from marking paint, and a sliding cover sits over the keyway.

What it is not is portable in any comfortable sense. At about 4.5 lbs it is the heaviest lock here by a clear margin, and the bracket is the part of the kit we trust least — a lock this heavy wants a proper holster or a bag rather than a frame mount that slides under load. The short shackle works in its favor: less clearance means less room to get a jack or a wedge into the gap.

Whether that is a good trade depends on where the bike sleeps. For errands in a quiet suburb, the Kryptolok does the same job with a pound less to carry and a better mount. For a bike that would cost a month's pay to replace, or a lock that stays at the same commuter rack all day, the extra steel earns its weight. The lock is not the problem; finding somewhere to put it is.

The first thing we noticed is that this lock is smaller than its listing suggests. The 7.76 by 5.02 inch figure describes the outside of the U; the usable gap inside is tighter than the Via Velo's, which is fine on a slim Sheffield stand and awkward on a fat-sleeved rack or a post with a sign bolted to it. What you get in return is a 17 mm shackle, thicker than the Kryptolok's, on a compact body with a five-foot cable in the box.

The bracket mounts sideways, which works on a seat post and less well on a down tube where a knee can catch it. Buy this if your regular spots are slim and you want a thick shackle on a small body; skip it if you lock to whatever is nearest, because some days the opening will not be big enough.

Sixteen millimeters is the headline, but a tenth of an inch of it is silicone cover, so the steel underneath is thinner than the number suggests. The cover is the better story anyway: it is soft enough to protect paint and grippy enough not to rattle. A four-foot cable and two rust-resistant keys round out a kit that asks very little of you.

The bracket is where this lock makes its first demand: it clamps to round tubes up to 30 mm, so aero seat posts and squared-off frame tubes are out. What we like is the weight — 2.67 lbs is easy to carry — and the silicone sleeve, a nicer touch than the vinyl on the mid-range locks here. What lets it down is the shape of the opening: 7.68 by 4.9 inches sounds roomy, but it is narrow once a frame, a wheel and a rack all want to be inside it.

On a small frame with skinny tubes and a slim stand, this is a good lock for short stops — light, inexpensive and covered where it matters. Take the bracket measurement seriously before you order, though; a lock that cannot be mounted is a lock that lives in a bag.

A Sold Secure Bronze badge on a budget lock is the reason this one made the list. Bronze is the entry tier of the Sold Secure scheme, so the lock has been tested against a baseline of real attacks rather than a marketing adjective. The 14 mm shackle is actually thicker than the Kryptolok's 12.7 mm, which tells you how little diameter on its own proves — the cylinder and the certification are doing the real work.

The rest of the package is generous for the tier: an opening of 7.68 by 4.56 inches that takes a chunky rack, a hexagonal PVC cover that survives weather better than plain paint, a 180 cm cable thick enough to reach both wheels, and a bracket that fits tubes from 20 to 42 mm, which covers most frames.

The bracket is also the piece worth replacing. It holds the lock, but it is the first thing to wobble, and a strap or a frame bag solves what the mount does not. None of that matters much if you already ride with a backpack, which is where this lock tends to end up anyway.

As a first U-lock, a second lock for a partner's bike, or one that simply lives at the office rack, it earns its place. The certification is what separates it from the other cheap locks here; everything else is ordinary in a way that suits the job.