Kryptonite Kryptolok 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

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

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!

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

Obviously it’s the brand that’s king of U-Locks. But I bet it someone had a battery powered angle grinder they could get through this. Catalytic converter thieves usually carry those around but your typical minor criminal may not have electric tools to steal your bike and so these U-locks definitely do the job. The connector to the bike took some time for me to get it right and sturdily secured to the bike. I originally mounted it on the top but then I decided to get another lock to lock my front tire to the bike. These two pairs well together on the bone. If I had two slider connections there wouldn’t be enough time but this other u-lock swivels to connect to the mounting bracket and therefore doesn’t need extra room to attach to the bike. Just wish I could still have room for a water bottle but locks are more important for city biking.

I have only used one other u-lock like this in the past, and didn't really look around in stores before buying this, so I didn't know what variations there could be. One of the ends of the U (can't see it while the end bar is on in the picture) has a slight curve to it which prevents the end bar from immediately dropping to the ground when the key unlocks it because you have to follow the curve to remove the end bar. My other u-lock does not have this feature so I was used to securing the end bar with my hands when I turned the key and got really efficient at it. Therefore, the curve on the end of the U kind of slows me down when I'm going to lock my bike up, but there's nothing in particular wrong with it - it's just different than what I'm used to and I can understand the advantage of it for some people. The other variation is the key has to be turned 360degrees in order to release the lock. My other u-lock just requires 180 degree turn. Again, no biggie - just different and a little awkward for me because of what I've been used to. The opening through the plastic guard piece for the key hole does seem a little small, so if the lighting is poor and I don't have my glasses on, I can see myself poking around a bit to find it, but it's not defective. Overall, this is a solid lock though, and I don't think I have to worry about anyone snagging my bike while I have it engaged, which is really the most important quality of the lock, so that's good.