Mount a U-Lock on Women's Bike Frame




Introduction: Mount a U-Lock on Women's Bike Frame

I've been so frustrated trying to find a way to mount a Kryptonite Series 2 u-lock on my Women's bike frame. The angle the seat post meets the top bar makes it impossible to secure the supplied bracket to the bike frame and the minimal space between the top and bottom bar leaves no room to do much with. So, after spending considerable time doing research online finding inspiration, I finally decided to adapt a few ideas and create my own mount.

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Step 1: What You Will Need

  1. U-Lock
  2. PVC Pipe - measured to the bar that locks to the "U". For me, I wanted it to be the full length of the larger half before the key/lock section (basically the part that says "kryptonite") and the width to be a snug fit. My piece was 3.5" long and had an opening of 1 3/8".
  3. Drill Bit - the same width, or slightly larger (by just a fraction of an inch) of the hole where the "U" inserts into the lock. I used a 9/16 drill bit.
  4. 2 Stainless Steel Hose Clamps - the size of one depends on your bike frame (1.5x or 2x bigger than your bike frame) and the other on the pipe you bought (should fit snugly before tightening). I used a 3/4" - 1-3/4" and a 1-3/4" - 2-3/4".
  5. Flat Head Screwdriver for the clamps (a 8mm hex bit socket fits it too which I found easier to use)
  6. Velcro - I used a piece of heavy duty tape (soft side) for the frame and a velcro tie for the U-Lock
  7. Good, durable tape that won't tear - I used electrical and repair tape
  8. Drill

Step 2: Mark and Drill Your Hole

The pipe should basically cover the length of the longer half of the u-lock bar before the black plastic that covers the key/lock section (the part that says "kryptonite"). With that in mind, you'll want to measure the center of where you'll drill your hole to where it matches when the pipe covers the bar. If your u-lock is like mine and you bought the same pipe, it won't be able to be cover the black plastic that covers the keyhole. So while it's perfect if you can drill the hole so the bar can rest and be held by the black plastic and still have the hole line up perfectly with the bar's hole, if you drill a fraction in the wrong direction it'll be hard to recover, so give yourself a little bit of wiggle room when you mark it.

Next, drill the hole. I started with a small drill bit for a pilot hole and then another one halfway between it and my 9/16". It's up to you as to what you prefer. Use a clamp if you have one or another sturdy way to secure the pipe as it will want to twist. I slipped mine through the "U" and secured it with my hand. Not the safest of methods but it worked.

Step 3: Secure the Pipe to the Frame

Wrap the frame a few times with some durable tape (electrical will ripe) where you want the top of the u-lock to be. The steel clamp will damage the frame if you aren't careful.

Using the screwdriver, unscrew the larger clamp and wrap it around the taped frame. Thread the smaller clamp on it too. Make sure you pay attention to the direction the screws are facing. Again, your preference. I preferred the screw on the clamp around the frame to be on the opposite side of where the pipe was.

Tighten the frame clamp first. This is where buying a size too big becomes important. The end should wrap around itself twice where you plan to secure the clamp for the pipe. While it's not absolutely necessary, I accidentally discovered that it's a lot more secure having it tightened on two layers of steel versus one. Yes, the supplies image shows two clamps of the same size but I had originally bought the extra large one, using it first, and when I redid it for the purpose of this instructable, trying the smaller one, it would shift easily. I switched back and it's completely secure.

Before completely tightening the frame clamp, insert the pipe through the pipe clamp and adjust it to where you want it (the clamp should be at the opposite end of the hole). Tighten the pipe clamp enough so that you can put the u-lock into it and adjust the hole to the right angle (the curve of the "U" should touch the frame). Then tighten everything.

Step 4: Velcro Your Frame

After tightening the clamps, you should be able to see where the u-lock will now naturally rest/hit/make-a-lot-of-noise-bumping on your frame. Obviously we don't want that. I solved this with velcro. First, I marked the spot and wrapped some electrical tape around it. Not necessary but might allow me to remove the heavy duty velcro when it comes time to. Second, I wrapped the loop side (soft side) of some industrial, heavy duty velcro around the frame once.

Step 5: Velcro the U-Lock

Using a velcro tie I wrapped the curve of the U with the hook side (pointy side) facing out. While it's not strong enough to latch onto the velcro wrapped around the frame, you can unwrap it easily and then wrap it around the frame for a strong hold.

I suppose you can wrap the industrial hook side velcro tape to the u-lock and not worry about wrapping and unwrapping, however i preferred the slightly softer, milder hooks on the ties so that it wouldn't possibly snag on as many things (in case I threw it in my backpack or something).

Step 6: When Using a Steel Cable

If you want to wrap your cable around the u-lock, make sure the bulk is between the u-lock and the frame otherwise your knees will risk hitting it. If your cable has a velcro tie you can use that instead of or in addition to the one on your u-lock.

Hope this helps someone else looking for an easy (and cheap) way to mount your u-lock on a women's frame!

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