The Kryptonite KryptoLok Series 2 Standard U-Lock combines the security of a U-lock with the versatility of a cable lock. With this lock, feel confident that your frame and rear wheel are fastened to the rack while the cable adds a deterrent to your saddle and front wheel, or maybe a pannier or two. It's our favorite U-lock for ease of use, with a bent-foot design that makes locking up a breeze. This lock has been around for a while, and it's nearing classic status; secure yet straightforward and iconic yet well-designed. The Series 2 won our Best Buy award for providing good quality at a more than decent price.
Kryptonite KryptoLok Series 2 Standard U-Lock Review
Cons: Cable is awkward to transport, rattles
Our Analysis and Test Results
Kryptonite's KryptoLok Series 2 is a mid-sized and mid-security U-lock that comes with a 4' cable and a mounting bracket to attach the U-Lock on your frame.
Our Best Buy award-winner received a Silver ranking from Sold Secure, an independent security testing organization that ranks approved products in Bronze, Silver and Gold categories. It also has a 2 out of 5-star rating from the Dutch organization ART. You might be wondering how U-locks could be separated into different categories since they are all pretty solid. Our Editors' Choice winner, the Kryptonite New York Standard U-Lock, earned a Gold ranking from Sold Secure (and 4 of 5 stars from ART) and the difference, as our tests have shown, is primarily in the locking mechanism. The New York Standard locks in both sides of the "U" and locks them so tightly that even after we used a grinder to cut through the lock, it was necessary to use a hammer to get the lock ends off the bike rack. Different bike racks or lock up scenarios require a thief to cut the U-lock twice.
The Series 2 resisted bolt cutters and a hacksaw and succumbed to the angle grinder's wheel in 39 seconds, which was about ten seconds longer than it took to cut through the Armbar Combo and ABUS Granit X-Plus 540. The Series 2 has one end of the "U" bent to make it easier to use (the "bent foot" is placed into the shackle first, then is used as leverage to secure the other side.) Even though this makes the lock easier to use (and what helps make it less expensive), it also means that a single cut from a grinder disables the lock. We gave the Series 2 Standard U-Lock a solid security rating regardless because the lock is solid and protects your bike well in most circumstances. Kryptonite also offers a $1,750 bicycle theft protection program, which indicates that they are willing to back this lock.
The 4' cable that is included with the U-lock should be viewed as a cumbersome step that deters a bike thief from choosing your bike, but it won't stop a thief with almost any cutting tool. Our security testing destroyed the cable with many different devices bike criminals are commonly found carrying, in as few as 2 seconds. That said, we liked that the loose cable could be thrown into your backpack if you knew you were going to leave your bike in a sketchy situation and wanted extra security. Part of theft deterrence is making your bike appear tougher and more time consuming to steal. Locking up with a cable and U-lock combo achieves that. The cable could also be a part of your everyday commuting kit whereby you lock up your front wheel without having to take it off.
Ease of Transport
Kryptonite includes its FlexFrame U bracket for you to install on your bike frame and mount your U-lock whenever you ride. While the cable can be connected to the U-lock and mounted, because it is non-coiled, it often came loose. A better idea is to put the lightweight cable in your backpack or pannier and secure the U-lock to the frame. This model is more lightweight and easier to transport than competing budget U-locks.
We know from experience that bomber bike locks sometimes come with lesser quality mounting brackets as if they are an afterthought. Our testers were suspicious of the webbing strap that holds the bracket in place; it seems that a piece of equipment holding 3 lbs of steel needs to be more burly to last. These brackets are replaceable, of course, and the convenience of mounting your bike to the frame is paramount. Throughout testing, though, this mount held its own and never failed us. When comparing this piece to the OnGuard Bulldog DT, the style of the OnGuard bracket was easier to mount and take off your lock, but it wasn't streamlined with the bike frame. It often brushed against our legs and impeded pedaling when moving fast. The Series 2 did rattle somewhat on bumpy rides. The ABUS Granit X-Plus 540 comes with our favorite U-lock mount, but it costs three times the price.
Ease of Use
The Series 2 Standard U-Lock is super easy to use. The bent foot of the "U" technology creates a hinge for you to put the straight side of the "U" shackle into the locking crossbar. The mounting bracket was also easy to install. Kryptonite includes an Allen wrench for installation and removal of the mount, which takes less than a minute on nearly any round frame. Make sure not to lose the wrench to tighten and adjust the mount as needed. It will loosen over time.
We liked this style's usability better than the dual locking mechanism of the OnGuard Bulldog. While more burly (and expensive) U-Locks require both ends to lock for security purposes, OnGuard's mid-range Bulldog dual locking function doesn't necessarily support its security rating (when cut, the Bulldog pulls apart easily). Therefore, we deem Kryptonite's bent foot technology as an innovative touch that boosted the ease of use rating.
The ability to lock up all removable parts of your bike is important in a variety of situations. Unlike products like the Kryptonite New York Fahgettaboudit U-Lock Mini, the Series 2 Standard U-Lock and OnGuard Bulldog come with 4' braided steel cables (with a plastic coating). These cables can be used to thread through wheels, saddle, panniers, trailer, or whatever you want to have a lock on.
These lock packages solve the problem of the pesky front wheel situation, whereby you don't want the hassle of taking it off every time you park your bike. You could even do away with the quick release tire skewers to further deter the opportunist thief.
This lock won the Best Buy award for being affordable yet well designed. The Series 2 is an all-around user-friendly bike lock with plenty of security for most people. If there is anything we learned from testing these locks, it was that it doesn't make sense to go with the cheaper cable locks. Spend the money once, make it a habit to lock your bike all the time, and keep your bike (and bike lock) yours. Especially with Kryptonite's bicycle protection offer, you can't go wrong here.
Kryptonite offers a good thing with a great price in the KryptoLok Series 2 U-Lock. It earned our Best Buy award for combining usability, transportability, and giving users the option of locking up their entire bike…all at an entry-level price.
— Ross Robinson