Kryptonite Kryptolok Standard U-Lock with 4-foot Flex Cable (13 mm steel)

If you’re shopping for a bike lock, you’re really deciding how much hassle you’re willing to deal with when you’re away from home. The Kryptonite Kryptolok Standard is built around a hardened 13 mm steel U-lock, and it adds a loop of flexible cable so you can secure more awkward frames and anchor points.

On paper, it’s the kind of lock that suits everyday commuting and regular parking stops—especially when you want decent security without turning carrying the lock into a daily gym session. Still, it’s not a magic shield: where and how you lock matters a lot.

Key takeaways

The headline here is the hardened steel body (13 mm) paired with a 10 x 22.5 cm U-lock size, plus a flex cable looped length of 122 cm. It’s also supplied with two stainless-steel “I”-shaped keys, which is a sensible touch for shared use or keeping a spare.

A double locking mechanism is another practical detail you’ll likely appreciate because it gives the lock more than one point of engagement when you close it. That said, you’ll still want to check your routine: the U-lock opening won’t fit every bike-and-rail combination, and you may find the cable part helps most in those “couldn’t reach” moments.

The essentials

This is a Kryptonite U-lock designed specifically for bicycles, combining two security modes in one: a rigid U-lock for the main attachment and a flexible cable loop for additional locking options. The U-lock is made from hardened steel, while the cable gives you a bit more freedom to work around seat posts, wheels, or fixed points depending on how your bike sits.

A good way to think about it is: the U-lock is your anchor, the flex cable is your workaround. If you regularly lock to thicker rails or you need to wrap around something that isn’t perfectly aligned, that cable can make the difference between “it fits” and “it doesn’t”.

What you’ll notice day to day

In real-world use, the U-lock format is usually straightforward: you position it through the area you want to protect, then engage the double locking mechanism. The hardened 13 mm steel body is the key security promise, but the usable experience comes down to the lock size.

With a U-lock size of 10 x 22.5 cm, you’ll want to confirm it lines up with your typical parking spots. If your usual anchor point is narrow or your frame geometry makes the gap between parts small, it should be easier to get a solid fit. If your anchor point is wide or far from your bike, you’ll probably lean on the flex cable loop to bridge the gap.

Everyday example

Imagine you finish work and need to lock quickly at a busy cycle rack where the bars are spaced differently from your last location. You slide the U-lock through the rear triangle and around the rack bar first. If the front wheel or a bag rail isn’t in a strong position, you use the 122 cm flex cable loop to secure an extra point—without having to contort the bike or hunt for a perfectly aligned gap.

Tech specs

• Name: Kryptonite Kryptolok Standard Bicycle U-Lock w/4-foot Flex Cable
• Type: U-lock with flex cable
• Material: Hardened steel (13 mm), plus flex cable loop
• U-lock size: 10 x 22.5 cm
• Cable loop length: 122 cm
• Locking mechanism: double locking mechanism
• Keys included: 2 x stainless-steel “I”-shaped keys

Where it shines (and where it may fall short)

This lock makes the most sense if you’re after a sturdy, hardened-steel U-lock that’s easier to fit to everyday situations thanks to the added flex cable. It’s also a reasonable choice when you need two keys and you’d rather avoid the faff of sourcing replacements.

However, it may not suit you if your parking routine often involves very large anchor spaces where a 10 x 22.5 cm U-lock simply can’t reach the way you need. In those cases, the cable loop can help, but it won’t change the fundamental size limits of a U-lock.

It’s also worth noting that even strong locks can be defeated if you lock poorly—leaving valuable components exposed or locking to weak, movable points. The hardware matters, but so does technique.

Who it’s for (and who should skip it)

It suits you if you’re commuting, riding regularly, or parking your bike in locations where you want a hardened-steel U-lock with some flexibility for day-to-day locking. If you often lock at racks or street-side anchor points that aren’t always perfectly aligned, the cable loop is a practical add-on.

It might not be a great match if you need a lock for unusual anchor setups where space constraints are tight in every direction. Likewise, if you’re looking for something that covers every scenario without thinking about fit, you’ll probably be happier choosing a design that’s more forgiving in size.

Is it worth it?

Buy it if you want a hardened 13 mm steel U-lock with a double locking mechanism, and you like the idea of adding a flex cable loop to improve how many real-world spots you can secure. It’s a sensible pick for everyday locking where you care about durability and want a more adaptable setup than a plain U-lock.

Don’t buy it if your typical anchor points regularly sit beyond what a 10 x 22.5 cm U-lock can comfortably cover. You may end up fighting the geometry, and even with the 122 cm flex cable, you still need a secure and sensible lock position.

If you’re weighing options, treat this as a practical middle ground: it’s more structured than a full cable lock, but more flexible than a basic U-lock alone. Pick it when fit and routine matter just as much as the lock’s steel.

Mini FAQ

Is this lock just a U-lock, or does it include a cable too? It’s a U-lock combined with a flex cable loop, so you can lock the bike with a bit more flexibility.

How many keys come with it? You get two stainless-steel “I”-shaped keys.

What’s the U-lock size? The U-lock is 10 x 22.5 cm.

Is the steel hardened? Yes—it's described as hardened steel with a 13 mm specification.

Will the cable help if the U-lock doesn’t reach? It’s designed to provide that extra reach for awkward anchor points, but the U-lock size still matters for your main attachment.