Front Wheel Kryptonite Bike Lock Hack




Intro: Front Wheel Kryptonite Bike Lock Hack

I had 2 kryptonite lock barrels that the U part was cut by some thieves with bolt cutters.

I trashed them, but then decided to keep them as evidence prints etc.

Had them laying around buried in my bike junkbox. I always loop my chain through the front wheel to prevent theft, in NYC I see plenty of bikes locked up missing one wheel.

So it occurred to me that I could use a kryptonite barrel if slightly modified.

Here are the results of my tinkering.

Step 1: Repurposing Kryptonite Lock Barrel

I decided the the easiest way to do it was to remove the brake posts from the front fork and replace them with modified bolts. I have disc brakes, so I didn't need the posts.

So I measured distance between brake posts and cut as needed.

The one on the left is the modified.

First I removed the plastic cover so i could reuse it.

Think I cut 1-3/4 inches from original barrel. I used a 4 inch grinder with a metal cutoff wheel.

Then you to cut a rectangular slot, do this after you figure out the bolt lock look at next step.

Step 2: Replace Brake Posts

Find bolt with head big enough to fit key side and when locked will not come out.

I used a bolt with a larger head on the opposite side, ended up grinding the both sides of the head

so the bolt is like a T, the images with the black bolt are T.

Being screws made it easy to adjust how snug the lock fit.

Step 3: Finishing Barrel Lock

After you have determined the distance of both bolt openings.

Mark and cut a rectangular slot for the T-bolt.

Again 4 inch grinder with metal cutting wheel, worked best for me.

Then cut plastic cover to size and reuse I used a box cutter.

Adjust bolt heights as needed.

Whoopie! no more looping chain through wheel.

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    6 Discussions


    2 years ago

    this is much better than the 3m chain i carry around


    2 years ago

    It would be great to see someone build a device to put the front brakes on when a bike thief got to a certain speed. Thinking of bike anti theft devices is a lot of fun.

    1 reply

    Reply 2 years ago

    haha or just diconnect your brakes and leave it unlocked at the top of a steep hill


    2 years ago

    Looks nice. The old Holland bikes have that in a cheaper version (like a ring that will close/open around the back wheel). There are two drawbacks with this design. A) you can easily crack it with a hammer since it is fastened to the frame with a weak nut. B) You can simply take the bike away with a pick-up since it is not locked to anything.

    1 reply

    Reply 2 years ago

    You could still lock it to something with a u-lock, these just make it so the wheel can't be taken as easily.