Kryptonite Kryptolok Standard Bicycle U-Lock w/4-foot Flex Cable

This is a seriously solid lock that gives you a real sense of security. The U lock alone is thick, heavy, and feels virtually tamper-proof. The included flex cable is a great addition, giving you more options to loop through your wheels or around awkward railings or posts. I’ve used it to lock both my frame and rear wheel with the U lock and then looped the cable through the front wheel. That versatility makes a big difference in urban areas where secure anchor points aren’t always ideal.While it is heavier than cheaper alternatives, the added weight feels justified by the protection it offers. I’d much rather carry a little extra bulk than come back to a missing bike. The lock mechanism is smooth, and the key turns easily without sticking, which I appreciate after past frustrations with cheaper locks.Pros:Heavy-duty and high qualityFlexible locking options with included cableSmooth key operationCons:A bit bulky for smaller backpacksIt might be overkill for low-crime areas

Good solid bike lock, needed to have gold standard for my bike insurance and Its suitably heavy and sturdy to make my bike feel safer.

I purchased this to leave at the office, so I don't have to drag my lock back and forth. It is a pretty standard 'D' lock, with a short (4 foot) cable. It has a handy velcro loop to tidy up the cable into a loop. It comes with two keys and a bracket to attach it to your bike (which I have not used).This is the KryptoLok Series 2, it is part of the Sold Secure range, at the Silver level (NOTE: the cable isn't recognised as Sold Secure and could be easily cut, it will only help prevent somebody pinching your wheels). Sold Secure Silver level offers enhanced security, but with cost compromises from the highest level (Gold) and often lower weight than Gold. Bronze is only recommended to stop opportunist theft. If you need a secure cable, there are Silver and Gold options on offer.The replacement guarantee from Kryptonite is full of weasel words and reading through it I decided I would almost certainly not get my money back in the event of a theft. The limit is £800 in the UK for reference.In use the lock works well and I can bolt my frame securely and protect my wheels with the cable. I cannot get the lock around the fence post (looks like a scaffold pole diameter) and through both the rear wheel and the frame. The lock mechanism works well and is easy to unlock, unlike some I own. I thread one end of the cable through a wheel, through an eyelet and then round the other wheel and put the loop into the D lock before I close it. I ride a 20" mountain bike frame on 26" rims, but if you have something with a longer wheel base, you might find that 4 feet is too short.All in all, I am happy with the purchase. I knew the guarantee would be almost worthless, but it's a decent lock and protects my cheap unfashionable bike in a low risk environment. I would not use this to leave my bike in a public place all day e.g. rail station, bike racks at school, etc. You'd want Gold for that.

I purchased this lock after reading that Oxford is the bike theft capital of Europe. I was unaware that such prizes were awarded and I'm sure that Kryptonite fund them in order to boost panic.In any case it worked for me and after doing some research I picked this lock. It seems to be the entry level serious lock. I've watched youtube videos of people having to try to cut through having lost their keys and clearly it means business.Having the cable along with the D-Lock is the best way forward. It allows you to lock another bike to yours, secure the front tire, and also loop round a second fixed post.The D-Lock is solid but light enough to be practical. The key system works well but does require regular oiling to ensure that it stays free moving. A couple of the 3 star reviews have noted that the lock seems to stick after a few months. A small spray of WD40 once a month will fix this and can easily be incorporated into general bike maintenance. The key is easy to use in cold weather, just make sure that you always push it to the very bottom of the lock before twisting or apparently you can damage the barrel.The mount is excellent, I have mine mounted onto the vertical bar of the seat tube and that seems to work very well. Some people seem to have struggled to mount the bracket. I have no idea why, it's incredible easy and has the advantage that the mount position can be moved it you add more accessories or simply feel the need to change the position.The Amazon price was the best I could find online and the Prime delivery sealed the deal. I would definitely recommend this lock, if my bike gets stolen now it's likely to be my own fault for drunkenly locking it to something silly, like a policeman.

Had this for a few months now, and it's done the job so far! Had 3 bikes stolen in the past using chain locks, so decided it was time for something a bit stronger, and now confident enough to leave my bike locked up pretty much everywhere! I know a few people have complained about the way it attaches to the bike, but I'm not quite sure why! It's never come lose on mine, even when doing a bit of off road. It is heavy, and it is big, but then unless you pay a fortune it needs to be if you want a strong lock to keep your bike safe. Despite this you can easily put it somewhere out of the way on the frame, I put mine sticking out from under the handlebars.The only drawback is that when I bought it I thought it came with a sort of insurance policy, such was there confidence in its strength! But it appears you have to pay extra for this. Probably still a good deal, but just incase anyone thought they were getting a real bargain!On the whole, it's a good solid lock, pretty reasonably priced, and all said and done, considering it's size, weight and strength, it's not that much of a hassle to tow around. Recommended!