Amazon.com: Customer Reviews: Kryptonite Kryptolok Series 2 Standard Bicycle U-Lock (4-inch x 9-inch) with 4-Foot Flex Cable
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on April 25, 2009
Kryptonite STD U Lock seems to be a very decent lock but it still can be "infiltrated" by a knowledgeable master thief/master lock picker in probably under 1 hour time. I'm not too worried since it is sizable, hefty looking and very heavy (4 lbs), so it looks bigger than what I saw on other bikes in the bike rack and my bike is only valued at $500. Plus most bike thieves are just simple crooks with a few tools (a bike crook in public with a 20 Pound Sledge Hammer, hacksaw, 42-inch bolt cutters, 12-inch screwdriver, 20-inch crowbar, and claw hammer will be very obvious and suspicious working for one hour on a lock).

Most bike thieves have limited time, looking for an "easy" and quick target. If you beef up your security with the bulky Kryptonite STD U Lock, odds are he'll go for a bike with a cheap lock (cheap chain or cable locks are a certain way to get your bike stolen in the bike rack). Many bikes are stolen because they're not even locked ("I'll just be a sec!"). Many bikes are also stolen because the locks are used incorrectly or left open/unlocked by mistake.

Kryptonite STD U Lock. The keys are very flimsy and forged with cheap metal so I won't be surprised in 12 months that they snap or are damaged. The Lock holder (cheap plastic) didn't work on my bike as the Lock is too big to fit anywhere so I just snug it into my rear rack.

Comes with a cable (be warned, it can be cut quite easily so don't use it as a "main attachment" to a pole, bike rack, etc, just use it to secure your rear or front tires with the U Lock attached to a pole, bike rack, etc, or run the cable through both the seat and the rear tire with the U Lock fastened to a solid object).

You should use a cable lock ONLY to secure your front or rear tire to the bike frame or bike rack. ALWAYS attach the U Lock to a solid, fixed object (lamppost, pole, road sign, fence, bike rack, etc). A cable lock is NOT a primary security tool to secure your bike. Never rely on a cable to anchor your whole bike, it can take someone a few seconds to cut through a cable lock. Always use a high quality U-lock or hefty chain as your MAIN locking device and cables as secondary devices.

In spite of AT LEAST 5 known attempts by petty German bike thieves to break through the Kryptonite STD U Lock, it's held up and has been an eminent tool in my bike lock collection (my secondary cable/cheap Chain locks securing my front tire have ALWAYS been cut).

In all, it's not bad for medium to low bike crime areas but don't use it ALONE for overnight, expensive bikes, big cities, dangerous zones or in dark desolate areas where a thief can use high powered tools or torches.

If you need more Security (you also will need to put up with the hassle of more Weight) go for:

Kryptonite New York Chain With EV Disc Lock Chain

OnGuard Brute STD 5001 U-lock

Kryptonite New York Fahgettaboudit U-lock

OnGuard Beast Chain
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on April 23, 2010
I like the lock. It's for a cheap ($100) bike. When I get a more expensive bike I'll buy the New York Std (yellow sleeve) lock.

I think the Kryptonite locks are a good value. But, the "protection offer" is almost insulting to my intelligence. You have to read the box carefully to realize you're only getting an *offer*, not protection. You can buy protection for 1-2 years. And, the terms of protection are so ridiculously tedious that you wonder why they even offer. The terms sound like they don't want you to use it.

Here's an example: You have to register your keys and serial number of your bike within 15 days. Why a time limit? I bought my lock before receiving my bike. Why should it matter to Kryptonite that I bought the lock 2-3 months ago?

Also, you can't transfer the lock/insurance to another bicycle. Why would Kryptonite care about that? Unless it's just a gimmick to sell more locks?

For a claim, you have to submit the broken lock. What if the thief takes the evidence with him?

I've heard that NYC messengers who ride expensive bikes buy two locks. They take one to a welder to cut/break. They register the keys (and buy protection) for that lock. They use the other other lock. If their bike is stolen, they submit the broken lock which they never used.

I can't blame them for doing that. Kryptonite sets the conditions that you almost have to do that if you want to protect a $1200 bike.

I would give the lock 5 stars. But, because of the fishy "protection offer," I only gave 4.
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on January 9, 2010
Now that I have the Kryptonite U lock and cable, I feel very comfortable leaving my bike parked at a bike rack on my school's campus where bike theft is common. It took a little practice getting used to locking and unlocking quickly as well as figuring out the best way to carry it while riding my bike (it's a bit heavy), but I would buy this same product over and over again and recommend it to anyone who wants to keep their bike safe from theft.
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on April 4, 2013
sigh. a crackhead stole my bike 2 days ago and this was the lock i had on it. now, we all know crackheads are pretty determined when it comes to stealing your s***, but i reckon they will had some trouble with the U-lock portion. i had used the cable with a seperate lock and key to get my bike attached to a tree. then i put the U lock through the frame, cable, and the wheel, essentially locking the frame and front wheel to render it unrideable. after a mere 5 hours of being outside, 10 feet from the door to my workplace, i found just the cable cut in two on the ground. i did not find the u lock anywhere. my guess is someone (maybe a crackhead, as i found out later theres tons of them who are notorious in that area for stealing s***, even dresses out of cars) saw it, then came back w some good clippers, clipped the cable, and walked off with the bike, to fiddle with the u-lock at home.

why do i still think this is a decent lock if my bike got stolen with it?

(im guessing) they couldn't crack the u lock. at least, not when they initially took it, because it was discarded like the cable) i think. well, eventually they probably will crack the u-lock, but i'd like to think it will give them some hell.

i'm buying it again, this time promising myself to use the U lock to get the bike onto a structure and then the cable through the tires and frame.

DO NOT USE THE CABLE TO LOCK THE BIKE TO A STRUCTURE OUTSIDE, especially in the Bronx. s***, dont even lock your bike up somewhere outside in the bronx, take it inside!
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on April 17, 2013
when I was deciding on where to attach the mount, I tightened it down in one spot (not too tight) then decided to move it... fail. the screw somehow cross threaded when I was backing it out, and would go any farther in or out. thus, the mount was too lose to use, but wouldn't come off. had to cut it off, scratching my bike's paint.
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on September 3, 2009
This lock works well. It is a little heavy, and I could not attach it to my bike anywhere, so I carry it in my pack. The cable makes it much easier to lock my bike to various racks, and makes it so I can lock up my friends bike at the same time. I would buy this again.
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on July 11, 2013
This lock was a great size, lightweight and presumably quite tough, however despite my 2 bikes being locked *securely* with these locks, they were stolen. I got the surveillance video footage from my building manager, and it turns out that it took the crooks less than 30 seconds to steal the bike. Unfortunately I could not figure out their tool (or some kind of vulnerability in lock) from the video due to an obstruction between the camera's line of sight and the bike wall mount.

All I know is that there is definitely something amiss with this lock. Either the crooks have figured out some sort of master key, or just a vulnerability like cutting the lock or something using a tool that takes no more than 30 seconds.

Oh and BTW, the lock was also gone. No bits and pieces (if any) on the floor and no metal shavings (I was looking for signs of an electric tool/cutter used).

Will not buy Kryptonite locks again, or the very least, not this model of lock. I do not recommend it.
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on June 17, 2009
I live in New York and as it's well known, bikes don't stay long in the same location! I left my bike for more than 3 days locked with this lock and found it right I left it when I came back! The additional cable is good and nice for the price. Hate the so called eazy mount though...
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on January 20, 2012
The U-lock is pretty solid and I never worry about chaining up my $500 bike for a few hours at a time. The cable is a nice addition to secure my front wheel, but I can see it being cut through pretty easily with a hefty cable cutter.
For its price and weight, I'm very happy with the lock.

Unfortunately, the lock holder is made of plastic and isn't that great; I stopped using it and just put the lock in my backpack. And worst of all.. THE KEY SUCKS. The metal is super malleable and easily deforms. After reading others' reviews, I have been very careful with the key and it is still dented like crazy. It still fits into the lock, but takes a little shimmying.
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on August 5, 2015
This lock can be easily pried opened with a 2'x4' or crowbar. The streets of San Francisco are filled with the skeletal remains of these useless locks. This lock has a design flaw in that it only locks one side of the U, making it very easy to pry open. It sucks that such a worthless lock is still being sold. The people who are selling this useless thing want your bike to be stolen. There are plenty of better more effective locks on the market. Don't waste your money on this. Buy a U lock that locks on both sides.
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