I've occasionally lamented that I couldn't leave my jacket at the bike. Also I would sometimes like to have a seat cover when I park out in the sun.
So I made me a jacket lock.
Remember when you were a little kid and you had those mittens that were connected by a string and strung up in your jacket so you couldn't lose them? That's what I did. I strung a 1/16" coated cable from wrist to neck to wrist, and ferruled a loop at each end. This cable just hangs out in my jacket, and you really don't notice it at all after the first time.
I have another length of the 1/16 coated cable, about 16 inches long, with loops at the end.
I draped the jacket over the seat, and ran the short cable through loop at the right wrist, through the wheel, through the left wrist, through the helmet D-rings, and to the helmet lock.
Now I have a seat cover, and I can leave my jacket locked to the bike!
I get that it just takes a decent set of wire clippers to unlock this, but 1, I had to give it a decent amount of effort with my wire cutters to trim the cable when it was convenient... with jacket and helmet on it, it's not convenient, and 2, it's still a decent deterrent
The bike with the jacket and helmet locked down
Right side. Green cable comes from the right sleeve, passes through the wheel to the left side.
Left side. Green cable comes from the right sleeve, through the wheel. Then through the cable from the left wrist, then to the helmet's D-rings, then to the helmet lock.
Comment