Tmiron writes – “Here is a neat and easy way to make a bike lock holder that stays on your bike. More specifically this is for the U-Bolt type bike locks. The cable ones, you can usually just wrap around the seatpost, but the U-bolt are a little more difficult to carry around while your biking. This can be built for around $3.50 (less if you already have some of the parts) and takes about 10 minutes.” – Link.
DIY Bike lock holder