What's the best method to stop a Kryptonite Mini d-lock scratching/chipping an aluminium frame? Stickers have already been applied as a first layer of protection.

  1. Is there something similar to the LifeLine Rubber Frame Protector that could wrap around the metal parts of the lock to prevent metal—metal contact? Or is this wide enough to work by itself?

LifeLine Rubber Frame Protector

  1. My second thought was to use Sugru? In this case, what is the optimal pattern to apply this to the d-lock? I thought several rings around the circumference of the lock at perhaps 1 cm intervalz? Or would a spiral be better? Or just a line on the inner circumference?
  • 1
    You can use something like 3M scotch 2228 tape on either the lock or the part of the frame you want to protect. Alternatively, you could wrap the lock in duct tape which is common practice with U locks.
    – Ben
    Apr 20, 2018 at 16:28
  • 2
    In addition to the rubber type tape listed you could also use a heavy coat of "plasti-dip" or similar, either the actual dip or the aerosol can. This leaves a rubber like finish.
    – Nate W
    Apr 20, 2018 at 19:47
  • Those coily things should expand fine, but as they get wider they also get shorter. From memory those are sized to go around outer cables, so by the time they are wrapped around a lock they might only be a turn or two long.
    – Criggie
    Apr 21, 2018 at 0:16
  • Bought some coil things and they don't work - too tightly wound and want to shrink back to their original diameter so slowly unwind themselves. Is there a more optimal pattern than a spiral for applying Sugru or some similar silicone-based protecting barrier? I like it better than the idea of inner tubes or heat shrink as it's going to be thicker and probably no heavier. Apr 24, 2018 at 11:29

4 Answers 4


Any protection must be applied to the bike, as dirt between the lock and bike will abrade both, but the bike is more fragile and valuable.

The only way to avoid dirt is to not use the bike. Stickers are good but have to be replaced fairly often. Cable ties and clear repair tape are also useful. I've used reflective tape on the seat stay of one bike where the D lock abrades the paint.

An old fashioned solution that works very well is to use an old inner tube on the bike, strapped or knotted in place

  • 1
    I have no interest in protecting the bike from dirt hence asking a question about damage from a metal lock. Apr 20, 2018 at 18:03
  • 1
    The dirt will cause damage. If you just wrap the lock in plastic you're wasting your time and choosing to damage your bike. All my D locks are coated in fairly soft plastic. When they get the chance they rub paint off, so I protect the frame
    – Chris H
    Apr 20, 2018 at 18:07

I use sleeves made of old inner tubes. It is soft enough to prevent scratches but still durable. Slide it over the "U" portion and put another piece over the lock body leaving holes in the tube for the U to slide into the catch.



I've successfully used modern heatshrink tube for a lot of things. You would get an appropriate size tube, and slip it over the open lock. Then apply heated air from a hairdryer or a hot-air gun tool and the tube shrinks, taking the shape of the object below.




As you can see it comes in different sizes, and shrinks by about 50% depending on the type.

I use 30mm and 35mm tube on handlebars, and 1.5mm tube on inner cables. For a lock, 8mm-15mm would be about right. For going over a chain, then 20mm-30mm might be appropriate.

If one layer is not enough protection, you can double up, or more!

And this stuff is cheap - a metre at alibaba is perhaps 1~3 dollars plus freight.

  • 1
    This is the method I ended up using. I made rings of thicker heatshrink under the full wrap to reduce the contact points as well. Feb 3, 2021 at 13:05

You can use something like 3M scotch 2228 tape on either the lock or the part of the frame you want to protect. Alternatively, you could wrap the lock in duct tape which is common practice with U locks. The best way to protect your frame from your lock is to wrap the lock in something soft because protecting the frame will only protect a certain spot. Wrapping around the lock like you suggest is a fine method.

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  • I was only ever planning on "protecting" the lock. So I guess my question is a) do those spiral cable wrap things stretch enough to go around a Kryptonite mini? b) what's the optimal pattern to use with Sugru? Apr 20, 2018 at 16:38

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