Kryptonite New York U-Lock M-18WL, Heavy Duty Anti-Theft Security Bicycle Lock, Ultimate Security Lock for Bicycles E-Bikes Scooters

The lock arrived quickly and was packed well. As for the lock itself, I've used it for a little over a week now, so I don't have any comments on durability. As others have noted, this is a heavy lock, no question. However, it is actually easy to carry on a bicycle. I strap it to my rear rack with Velcro straps and it does not rattle while the bicycle is in motion. I don't really notice its weight while bicycling either. Thus far, the locking mechanism has operated smoothly. The 'U' portion fits easily through a wheel, the bicycle frame and a bicycle stand anchor point. It looks substantial, or at least more substantial than the locks on other parked bicycles at my workplace, so I'm hopeful that will buy me some additional security. Will comment later on durability, though I've had used two earlier generation Kryptonite locks for years without any problems. I don't expect to have problems with this one as well. December 2016: I've used this lock without any problems nearly every weekday. The lock has been exposed to rain and mud without any effect on the lock mechanism. So far, no signs of rust. The added weight is really no problem.

Solid construction and easy to use. Light weight compared to other models and feel my bike will be there when I get back. .

This is the lock you’re looking for. Solid, big, secure. Very heavy, maybe 8-10lbs. I use it to lock my fat-tire e-bike. Fits around the 2” pipe rack and the rear rim/tire.

This is not the heaviest lock out there (the almost comically large Altor SAF takes that prize) but the M-18 is seriously heavy. That makes it a little clumsy to lock and unlock, but that's a small price to pay for excellent thief-deterrence and good security. Certainly no casual thief is going to get through this lock, and it'll at least put up a fight against an angle grinder. It's essentially a big Fahgettaboudit Mini; I need the size because my e-bike's frame is not as slender as a regular bike. I don't notice the weight when I'm carrying it on the bike. I don't love the deadlock scheme it uses; keeping the key in the lock in the unlock position while deploying the lock feels clumsy to me, but as a deadlock, it does mean you can't accidentally leave it unlocked. Once you get used to the weight and the way the lock works, it's quick to deploy on a good bike rack, and it certainly looks more authoritative than the locks on most other bikes. Bottom line, I like it very much. Short of a lock made of adamantium, I feel very comfortable with it on the bike when I'm away.

Súper protección a mi bicicleta muy recomendable

Worth the ccost to protect my bicycle investment. The light attachment to one of the keys keeps slipping off the key making the light frustrating and undependable.

This Lock is in New York Lock it’s very highly recommended, it keeps people away. If they see it, they’re gonna get intimidated, they will think twice of robbing you. It’s an intimidating, and that’s what you wanna do intimidate thieves.

What can you write about a lock, any lock, for a bike, ebike, or even motorcycle? I mean, this one seems strong as all get out. Gosh knows it's heavy enough. I use it on my $2,000 ebike. But I know darn well: ANYBODY with a $65, rechargeable grind-tool, can probably cut through this, or ANY hunk of metal -- even were it 50% thicker -- in less than 45-seconds. So, this lock is arguably among the best available, thus it'll probably "anchor" your 2-wheels in most situations . . . until the skivvy dude with the $65 grinder decides he wants YOUR wheels.