I’ve ridden a lot of ebikes. Name an ebike brand from the last six years, and I’ve probably had it locked up in the bike garage during testing, and locked up again in a wide range of places in New York City.

Around trees and lamp posts when I had to, weirdly thick bike-parking hoops, to fences and gates, and even an indoor balcony once. I’ve also tested nearly all the bike locks out there, and I’ve come to a personal preference that I’ve turned into a maxim: U-locks are simply better than the other two types of bike locks.

the superiority

When bringing a chain along on a ride so I can lock it up outside a store or gym, I have to wrap the chain around the top bar of the frame, if the bike has one. It slides around, it dangles. And it can add eight pounds to the bike’s weight.

U-locks, given the same resistance to bike thieves’ cutting tools, are significantly lighter than chain locks. They’re easier to carry, too. Kryptonite and Abus have U-locks that come with frame-mounted brackets that, in my experience, don’t slip. Hiplok, instead, is designed to tuck into a person’s belt for transportation when riding.

With their gently curving U shape, they also tend to fit into any gap suitable for locking up a bike. Although it seems counterintuitive, given that they lack the incredible flexibility of bike chains, I’ve almost never come across a potential lock-up spot that couldn’t be used to secure a bike.

Folding locks, I never enjoyed using. Although convenient to carry on the bicycle when riding, often tucking into a holder mounted where a water bottle holder normally goes, they’re finicky when it comes to real-world use.

You can’t always choose your lock-up location when you park your bike. Whatever you see before you when you pull up to the café or post office is what you get, and what you get is often weirdly shaped and oddly angled.

Folding locks’ inflexible links make it hard to thread them through all but the widest lock-up points, which rarely exist outside swanky office bike garages. I’ve had to abandon too many public bike parking hoops and fences because the rigid links’ Z-shaped zig-zagging makes it too awkward to fit through a gap.

There’s an exception to the U-lock’s supremacy, though. When all I want is a lock for around the home, which I won’t take with me on my rides, then in certain circumstances I lean toward a chain, such as the Abus Granit.

Though several times heavier than u-locks of comparable cutting resistance, it doesn’t matter if you’re not carrying it anywhere, and it’ll stay at home, used only when you return to lock up your bike at night.

Chains are long and ultra-flexible. Locking a bike to a hard-to-reach iron-bar fence? The chain will reach. Or there’s a particularly thick pole that a U-lock can’t go around? The chain will. Want to lock up more than one bike with one lock? I regularly lock up three with an Abus Granit chain lock.

As a general-purpose lock, though, the chain is too heavy and inconvenient to bring along on rides, and if your at-home lock-up point isn’t too awkward, the U-lock suffices just as well as the chain for a single bike, too.

Someday, they may invent an entirely new format of bike lock. Until then, the U in U-lock stands for unmatched.