KryptoniteKryptolok Bike U-Lock, Heavy Duty Anti-Theft Bicycle Lock Sold Secure Gold, 12.7mm Long Shackle with Mounting Bracket and Keys, Ultimate Security Lock for Bicycles E-Bikes Scooters

I got this lock to replace my old Keeper 2. Both locks are great for locking bicycles, nothing short of power tools will get past them. And power tools are conspicuous. The keeper 2 was a great lock, despite the key sometimes being sticky, but the mount that came with the lock wouldn't fit on my bike well and wore out over time. Eventually, it fell off the mount while I was riding my bike, and I was unable to find it. I bought this lock to replace. Already, this lock is of a noticeably higher quality than the keeper 2. There is a plastic covering for the keyhole to prevent wear, it is much sturdier, and the locking mechanism itself seems more solid. Again, however, the mounting mechanism is tedious to set up (I can't get mine on correctly again, it is weirdly designed and I couldn't find any instructions for it), but it seems to be of a higher quality than the one that came with my keeper 2. I am still, however, worried that after prolonged use the mounting mechanism will wear out and the lock will fall out again, but that's nothing against the lock itself which is what you really pay for.What gets this lock 5 stars is the customer service. I had ordered the theft protection that came with my keeper 2, which cost a few bucks (15ish?) for 3 years. I was worried that my protection as tied to the lock, but after 2 minutes with the rep I had already given her the information on the new lock and she promised me she would transfer the coverage. I also only had to wait on hold for 2 or 3 minutes, which for any customer service is a huge plus.

Very satisfied with the heavy duty U-Lock. As a fitness errand running cyclist, the device is just fine even being relatively heavy in weight compared to smaller ones. With all the gears on my bike, I don't notice the extra load at all. Really needed the additional length this lock offers so I could latch my bike to a greater number of fixed objects (I always keep my bike in line of sight--never rely on any one lock). But this locking system is plenty secure enough for my purposes. Go for it if you are okay carrying a little more weightiness than you usually do. I carry the lock on top of my rear saddle bags that are connected to my rack. Works fine!

Great!!! As always kryptonite have great products. Bought LS version, long one. Much better for electric bike, you can lock wheel and frame together.

This lock is heavy, monstrously large, and does its job. I didn't have the issues others noted re: attaching the adapter to my frame - worked fine for me, although I'd caution that because the lock is SO big, it's hard to find a spot large enough to attach it. The lock cylinder can be a little finicky in terms of locking/unlocking - if everything isn't aligned just perfectly, it won't go. It took me a few frustrated attempts to figure out what was going on, and now it's no big deal.Overall, awesome product, and it's kind of nice to have such a large lock that it's not hard at all to find something to lock my bike (frame and front wheel) to. However, I did just order a mini version (a full 5" shorter), because I just don't always need such a huge lock.

I've been using this lock for 4 or 5 months now.... Gets 5 stars in consideration of reasonable price... I've seen flimsier locks for about the same price in storesThe Pros-1. I have a hybrid upright position bike and for the those familiar with these bikes you know there tends to be a greater distance from the frame to the tire making it necessary to have a longer bike lock to secure both onto bike parking racks. The length on the lock works great for this purpose.Areas of concern, but not a deal breaker as far as I'm concerned2. The flex frame bracket is flimsy but if secured on the right spot and tightly it will work out just fine. Took me a good deal of time to find the right spot since I'm INCREDIBLY not manually inclined as well as the initial installation about an hour or so *(disclaimer it does come unloose and requires tightening from time to time and I also require a reusable zip tie to secure it to frame else the lock would hit my leg) it works because I managed to rest it on the water bottle holder screws as well..... don't know if it would hold otherwise??? again not manually inclined and I managed to figure it out so you can probably as well. instructions are useful enough to get the job done.Cons-1. a bit heavy.... not a big deal.... there is no way of getting around this because of the length.2. the locking mechanism can be less than perfect at times but goes away with regular use. Not as big of a problem as others have noted here. ((***** have not rode in freezing temps yet....all and all this is a good bargain for the price without going with your more expensive and heavier alternatives considering the length of the lock.Hope this is helpful

Very fair price point for a super strong and dependable bike lock. There are very hard to get through and often times keep a potential thief from even trying.