Kryptonite Transit FlexFrame-U Bracket Bike Lock Mount, Lightweight Mounting Bracket for Kryptonite U-Locks 13mm-16mm Shackles, Bicycle Attachment Accessory

This is a really great mount, it can fit onto a normal round tube bike or it can also fit onto a square or rectangle shaped tube like on some of the newer bikes. I bought 2 of these and mounted one on my bike and the other on my wife's bike, so the lock can switch from bike to bike. There are some reviews that say this is a bad piece of equipment because it does hold properly or some other reasons and I can tell you this mount will mount on your bike very securely and easily, but there is a right way to do it and a wrong way. Make sure the strap is wrapped around the tube securely and snugly before you tighten the screw that holds it in place and it will be in place and won't move at all when done. Another thing to note about this is that when your lock is placed into this mount it is held onto the bike securely and won't come off, but the lock can still move back and forth. The silver piece on the lock that slides into the mount and locks in place holds the lock to the mount but it just slips over the round bar of the lock and can spin in place, which means when locked in it can still back and forth. I use a small velcro strap to hold the round bar side of the lock w/o the silver piece to the frame or where you decide to place it. (I know this sounds confusing, but you will know what I mean when you get it). It is a good mount and I completely recommend it to everyone. (the picture of the lock mounted into the downtube bottle mounts looks great, but the lock will not stay in that upright position, it will fall to either side and hang down unless you hold it in place with a strap around the lock and downtube)

I bought this bracket setup since the original would not fit on today's larger frame tubes. This bracket is pretty versatile due to its universal mounting system which allows it to be mounted in several locations on the frame. Seat stem, top tube, down tube, are all reasonable spots to consider depending on your riding position and bike frame compatibility. I chose the seat stem just below the top tube. The mount itself is easy to install with the padded strap/buckle and the allen 4mm hex nut which attaches the swivel/rotating locking mechanism. I rotated mine enough so the u-lock would angle in the same orientation as the seat stays. The system comes with two different sized collars that lock into the mount. They both fit my larger u-lock. With the smaller collar you would have to trim off the rubberized plastic protecting cover where the larger one fits over the top of the protective covering but it does move around a bit even when really tight. I rotated mine just enough to tuck the top under the seat so my leg would not brush against it. I would recommend if you really like the mounting position to use some loctite blue on the hex nut for the mount and on the set screw on the locking collar so they don't come loose which is what I did. The kit also comes with a hex wrench, however I used a longer one for a bit more leverage. Just for interest I would like to see images of the failed attempts to install this on a bike to try to determine why. Overall very nice and it works well and as intended. As far as durability I am not sure but in 6 months I will post something if I change my opinion.

This lock is a tragedy, the hubris of a successful lock company, a fleecing of its consumers (It's a cliche story, I know.) When I originally bought the lock, this bracket technology was included, so I mounted it to my seat tube assuming that it would work....It did not. It stayed in place maybe a few weeks before sliding down toward the petals, towards Hades. Then, I tried it in multiple other places, and it also remained where mounted for just short periods. I gave up, cursed the gods, and I tossed it. A couple years later, tired of the weight of it in my bag or the rattle of it on my cargo rack held in place by a bungee cord, I decided to buy another bracket, thinking that maybe the first one I had was defective. Clearly, only my lack of foresight was, similar to whoever made this lock, perhaps the lowly people of the Iron Age. The replacement bracket seems even worse, if that is possible, devised by . The final and most recent failure for me was when the blinking thing actually stopped me from moving, as the lock swung back in forth, clashing like Sympleglades against my shins interrupting my pedaling. I threw the lock in my bag and the bracket in the trash, which of course, slid right down to the bottom, likely out of habit or perhaps because that is where it belonged (Poor lock mount like Oedipus, The Fates were against you.) I hate having to put the lock in my myriad of other storage spots, but I've conceded defeat to this Herculean task. I've also decided that I likely won't buy another Kryptonite lock because I don't really have faith in a company that cannot design a simple mounting bracket. Presumably, a sound lock is more difficult to create than a mount for said lock but...? Their designer/engineer should have his liver pecked at every day like Prometheus (Okay, maybe not that bad but note to engineer--you don't have Impostor Syndrome; you're really don't belong there. Consider yourself more of a hobbyist than anything else) In the words of Comic Book Guy, "Worst Mounting Bracket, ever."

I haven't left an amazon review in well over several years even though I buy a lot from here. I bought this lock out of a friend's suggestion and he helped me install it. Overall, this review comes from ~2 months of dealing with this thing and the frustrations that came from it. First, the shackle for mine (16mm?) did not fit immediately over the end of the U-bolt. Looking into the geometry, the shackle was nowhere near circular and had to be filed down. I physically had to sand it + the U-bolt for several minutes and then use a lubricant to get it to finally slide over to its resting place. First issue solved. Then another part variation held me up but I dealt with it for a few weeks. The shackle would then not slide easily into the plastic lock/strap system. It wouldn't click into place unless you used considerable force. This alone kept loosening the overall strap and scuffing my frame. Boo. I left this alone for several weeks. It was fine until just ordinary riding would pop the U-bolt out of place over rougher roads. Imagine dropping your f****** lock on a busy shared road in downtown Seattle? Yeah, no. I again sat down, this time for about 2 hrs, sanding and filing certain edges in the hopes that I'd finally found the interfering sections that prevented it from locking easily, securely, and reliably. It finally locks into place using a firm pull as opposed to how I got it straight out of the packaging. It now works great and as intended. I am now very content... after several hours of fixing it and the harrowing adventures of stopping in busy streets to not get run over. Hopefully nobody else has had this issue and I got a crappy one from the lot, but buyer beware I suppose. update: nope, never mind. I still hate this. Will buy different item.

Assembly is a bit tricky, and the Allan Key head on the screw is very weak and and gets stripped if you over tighten. Otherwise, this is an excellent product. Very sturdy and it looks like it will be durable.

I have two bikes, and I needed an extra lock mount so I could use my Kryptonite New York lock with both of them. It fits around the vertical post, just like on the other bike, and whichever bike I use, I can have my lock with me!

Does the job! Holds the lock well in place. Not too heavy, flimsy or loose. Looks and feels sturdy.

This has made my life easier since I no longer have to lug my lock in my backpack when I'm on my bike. It was a bit of a pain to install, but mostly that had to do with finding a place on my frame where the lock wouldn't hit my legs when I pedal (I have a large lock and it didn't fit inside the frame, so I ended up putting it on the seat tube). I also have a non-standard lock - I bought it years ago and it is a different diameter than either of the attachments that came with the bracket. But I was able to use some of the pieces of rubber that I cut off the lock to fill in the gap between the lock and the larger of the two attachment pieces, and now I'm all set. Attaching the bracket to the bike itself was quite simple, and putting the lock on and taking it off the bike are a breeze. Great product, solved my problem without breaking the bank.